research article on the finite volume element method for
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Hindawi Publishing CorporationJournal of MathematicsVolume 2013 Article ID 464893 13 pageshttpdxdoiorg1011552013464893
Research ArticleOn the Finite Volume Element Method for Self-AdjointParabolic Integrodifferential Equations
Mohamed Bahaj1 and Anas Rachid2
1 Department of Mathematics and Computing Science Faculty of Sciences and Technology Hassan 1st UniversityBP 577 Settat Morocco
2 Ecole Nationale Sueprieure drsquoArts et Metiers-Casablanca Universite Hassan II Mohammedia-CasablancaBP 150 Mohammedia Morocco
Correspondence should be addressed to Anas Rachid rachidanasgmailcom
Received 26 December 2012 Accepted 15 April 2013
Academic Editor Mario Ohlberger
Copyright copy 2013 M Bahaj and A Rachid This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited
Finite volume element schemes for non-self-adjoint parabolic integrodifferential equations are derived and stated For the spatiallydiscrete scheme optimal-order error estimates in 119871
21198671 and 1198711199011198821119901 norms for 2 le 119901 lt infin are obtained In this paper we also
study the lumped mass modification Based on the Crank-Nicolson method a time discretization scheme is discussed and relatederror estimates are derived
1 Introduction
The main purpose of this paper is to study semidiscreteand full discrete finite volume element method (FVE) forparabolic integrodifferential equation of the form
119906119905minus nabla sdot (119860 (119909 119905) nabla119906) minus int
119905
0
nabla sdot (119861 (119909 119905 119904) nabla119906 (119904)) 119889119904
= 119891 (119909 119905) inΩ times (0 119879]
119906 = 0 on 120597Ω times (0 119879]
119906 (sdot 0) = 1199060 inΩ
(1)
where Ω is a bounded domain in R119889 119889 = 2 3 withsmooth boundary 120597Ω and 119879 lt infin Here 119860(119905) a non-self-adjoint second-order strongly elliptic and119861(119905 119904) an arbitrarysecond-order linear partial differential operator both withcoefficients depending smoothly on 119909 and 119905 119891 = 119891(119909 119905)
and 1199060(119909) are known functions which are assumed to be
smooth and satisfy certain compatibility conditions for 119909 isin
Ω and 119905 = 0 so that (1) has a unique solution in certainSobolev space Problem (1) occurs in nonlocal reactive flows
in porousmedia viscoelasticity and heat conduction throughmaterials with memory
Finite volume method is an important numerical toolfor solving partial differential equations It has been widelyused in several engineering fields such as fluid mechanicsheat and mass transfer and petroleum engineering Themethod can be formulated in the finite difference frameworkor in the Petrov-Galerkin framework Usually the formerone is called finite volume method [1] marker and cell(MAC) method [2] or cell-centered method [3] and thelatter one is called finite volume element method (FVE)[4ndash9] covolume method [10] or vertex-centered method[11 12] We refer to the monographs [13 14] for generalpresentation of these methods The most important propertyof FVE method is that it can preserve the conservation laws(mass momentum and heat flux) on each control volumeThis important property combined with adequate accuracyand ease of implementation has attracted more people to doresearch in this field
Recently the authors in [8 15] studied FVE method forgeneral self-adjoint elliptic problems The authors in [16]presented and analyzed the semidiscrete and full discretesymmetric finite volume schemes for a class of parabolicproblems In [6 7] the authors have studied FVE for one- and
2 Journal of Mathematics
two-dimensional parabolic integrodifferential equations andhave obtained an optimal-order estimate in the 1198712-normTheregularity required on the exact solution 119906 is 1198823119901 for 119901 gt 1
which is higher when compared to that for finite elementmethods
The aim of this paper is to study the convergence of FVEdiscretization for a nonself-adjoint parabolic integrodifferen-tial problem (1) Both spatially discrete scheme and discrete-in-time scheme are analyzed and optimal error estimates in1198712 and 119867
1 norms are proved using only energy method Wealso explore and generalize that idea to develop the lumpedmass modification and 119871
119901 estimates 2 le 119901 lt infin Ouranalysis avoids the use of semigroup theory and the regularityrequirement on the solution is the same of that of finiteelement method Furthermore based on the Crank-Nicolsonmethod the fully discrete scheme is analyzed and the relatedoptimal error estimates are established
This paper is organized as follows In Section 2 we intro-duce some notations and present some preliminary materialsto be used later The Ritz-Volterra projection to finite volumeelement spaces is introduced and related estimates are carriedout in Section 3 In Section 4 we estimate the error of thefinite volume element approximations derived in the previoussection In Section 5 the lumped mass is presented andoptimal estimates in 119871
2 and 1198671 norms are obtained Finally
the Crank-Nicolson scheme is studied in Section 6
2 Finite Volume Element Scheme
In this section we introduce some material which will beused repeatedly hareafter Throughout this paper 119862 (withor without index) denotes a generic positive constant whichdoes not depend on the spatial and time discretizationparameters ℎ and 119896 respectively
21 Notations We will use sdot 119898and | sdot |
119898(resp sdot
119898119901and
| sdot |119898119901
) to denote the norm and seminorm of the Sobolevspace119867119898
(Ω) (resp119882119898119901(Ω)) The scalar product and norm
in 1198712(Ω) are denoted by (sdot sdot) and sdot respectively Let1198670
1(Ω)
be the standard Sobolev subspace of 1198671(Ω) of functions
vanishing on 120597ΩThe weak form of (1) is used to find 119906(sdot 119905) [0 119879] rarr
1198671
0(Ω) such that
(119906119905 V) + 119860 (119905 119906 V) + int
119905
0
119861 (119905 119904 119906 (119904) V) 119889119904
= (119891 V) forallV isin 1198671
0(Ω)
119906 (0) = 1199060
(2)
where
119860 (119905 119906 V) = intΩ
119860 (119909 119905) nabla119906 sdot nablaV
119861 (119905 119904 119906 (119904) V) = intΩ
119861 (119909 119905 119904) nabla119906 (119904) sdot nablaV
(3)
LetTℎbe a decomposition ofΩ into triangles (for the 2D
case) or tetrahedral (for the 3D case) with ℎ = max ℎ119870 where
ℎ119870is the diameter of the element119870 isin T
ℎ
In order to describe the FVEmethod for solving problem(1) we will introduce a dual partition Tlowast
ℎbased upon the
original partition Tℎwhose elements are called control
volumes We construct the control volumes in the same wayas in [7 17] Let 119911
119870be a point of 119870 isin T
ℎ In the 2D case
on each edge 119890 of 119870 a point 119902119890is selected then we connect
119911119870with line segments to 119902
119890 thus partitioning 119870 into three
quadrilaterals 119870119911 119911 isin 119885
ℎ(119870) where 119885
ℎ(119870) are the vertices
of 119870 Then with each vertex 119911 isin 119885ℎ
= cup119870isinTℎ
119885ℎ(119870) we
associate a control volume 119881119911 which consists of the union of
the subregions119870119911 sharing the vertex 119911 (see Figure 1)
Similarly in the 3D case on each of the four faces 119878119894 119894 =
1 4 a point 119902119878119894 119894 = 1 4 is selected and on each of the
six edges 119890 a point 119902119890is selected On each of the two faces 119878
1
and 1198782of119870 sharing an edge 119890 we connect 119902
119878119894 119894 = 1 2 with 119902
119890
andwith 119911119870by line segments thus partitioning119870 into twelve
tetrahedron 119870119911 119911 isin 119885
ℎ(119870) (see Figure 2) Then for 119911 isin 119885
ℎ
the control volume119881119911consists of the union of the subregions
119870119911sharing the vertex 119911 Thus we finally obtain a group of
control volumes covering the domain Ω which is called thedual partitionTlowast
ℎof the triangulationT
ℎ We denote by 1198850
ℎ
the set of interior vertices and 119873ℎ= 1198850
ℎ For a vertex 119911
119894isin
1198850
ℎ let Π(119894) be the index set of those vertices that along with
119911119894are in some element of 119879
ℎ(Figure 2)
There are various ways to introduce a regular dualpartitionTlowast
ℎ In this paper we will also use the construction
of the control volumes in which we let 119911119870be the barycenter
of 119870 isin Tℎ In the 2D case we choose 119902
119890to be the midpoint
of the edge 119890 (see Figure 3)In the 3D case we choose 119902
119890to be the midpoint of the
edge 119890 and 119902119878119894to be the barycenter of the face 119878
119894(Figure 4)
We call the partitionTlowast
ℎregular or quasiuniform if there
exists a positive 119862 gt 0 such that
119862minus1ℎ2le meas (119881
119911) le 119862ℎ
2 forall119881
119911isin T
lowast
ℎ (4)
If the finite element triangulation Tℎis quasiuniform
that is there exists a positive 119862 gt 0 such that
119862minus1ℎ2le meas (119870) le 119862ℎ
2 forall119870 isin T
ℎ (5)
then the dual partition Tlowast
ℎis also quasiuniform
Based on the triangulation 119879ℎ let 119878
ℎbe the standard con-
forming finite element space of piecewise linear functionsdefined on the triangulation 119879
ℎas follows
119878ℎ= V isin C (Ω) V|119870 is linear forall119870 isin 119879
ℎ and V|Γ = 0
(6)
Let 119868ℎ
C(Ω) rarr 119878ℎbe the standard interpolation
operators such that
119868ℎ119906 = sum
119911isin1198850
ℎ
V119911(119905) 120593
119911(119909) forallV isin 119878
ℎ (7)
where 120593119911119911isin1198850
ℎ
are the standard basis functions of 119878ℎand
V119911(119905) = V(119905 119911)
Journal of Mathematics 3
z
Vz
(a)
z
K
Kz
zK
(b)
Figure 1 (a) A sample region with blue lines indicating the corresponding control volume 119881119911 (b) A triangle 119870 partitioned into three
subregions119870119911
Kz
qs1 qs2
qe
zK
z
Figure 2 A tetrahedron 119870 partitioned into twelve subregions119870119911
22 Construction of the FVE Scheme We formulate the FVEmethod for the problem (1) as follows Given a 119911 isin 119885
0
ℎ
integrating (1)1 over the associated control volume 119881119911and
applying Greenrsquos formula we obtain an integral conservationas follows form
int119881119911
119906119905minus int
120597119881119911
119860 (119909 119905) nabla119906 sdot 119899119889119904 minus int120597119881119911
119861 (119909 119905 119904) nabla119906 sdot 119899119889119904
= int119881119911
119891 (119909 119905)
(8)
where 119899 denotes the unit outer normal vector to 120597119881119911
Let 119868lowastℎ C(Ω) rarr 119878
lowast
ℎbe the transfer operator defined by
119868lowast
ℎV = sum
119911isin1198850
ℎ
V (119911) 120594119911 forallV isin 119878
ℎ (9)
where
119878lowast
ℎ= V isin 119871
2(Ω) V
119894
1003816100381610038161003816119881119911is constant forall119911 isin 119885
0
ℎ (10)
and 120594119911is the characteristic function of the control volume119881
119911
Now for 119905 gt 0 and for an arbitrary 119868lowastℎV we multiply (8)
by V(119911) and sum over all 119911 isin 1198850
ℎ Then the semidiscrete FVE
approximation119906ℎof (1) is a solution to the following problem
find 119906ℎ(119905) isin 119878
ℎfor 119905 gt 0 such that
(119906ℎ119905 V
ℎ) + 119860 (119905 119906
ℎ V
ℎ) + int
119905
0
119861 (119905 119904 119906ℎ(119904) V
ℎ) 119889119904
= (119891 Vℎ) V
ℎisin 119878
lowast
ℎ
119906ℎ(0) = 119906
0ℎisin 119878
ℎ
(11)
Here the bilinear forms 119860(119905 119906 V) and 119861(119905 119904 119906 V) aredefined by
119860(119905 119906 V)
=
minussum
119911isin1198850
ℎ
V119894 int120597119881119911
119860(119909 119905) nabla119906 sdot 119899119889119904 (119906 V) isin ((1198671
0cap 1198672) cup 119878ℎ) times 119878
lowast
ℎ
int
Ω
119860(119909) nabla119906 sdot nablaV119889119909 (119906 V) isin 1198671
0times 1198671
0
119861 (119905 119904 119906 V)
=
minussum
119911isin1198850
ℎ
V119911 int120597119881119911
119861 (119909 119905 119904) nabla119906 sdot 119899119889119904 (119906 V) isin ((1198671
0cap 1198672) cup 119878ℎ) times 119878
lowast
ℎ
int
Ω
119861 (119909 119905 119904) nabla119906 sdot nablaV119889119909 (119906 V) isin 1198671
0times 1198671
0
(12)
Let
119906ℎ=
119873ℎ
sum
119895=1
120572119911(119905) 120593
119911(119909)
120572 (119905) = (1205721(119905) 120572
2(119905) 120572
119873ℎ(119905))
119879
(13)
Then we can rewrite scheme (11)1 as systems of ordinarydifferential equations as follows
119872ℎ1205721015840(119905) + 119860
ℎ(119905) 120572 (119905) + int
119905
0
119861ℎ(119905 119904) 120572 (119904) 119889119904 = 119865
ℎ(119905) (14)
4 Journal of Mathematics
z
Vz
(a)
z
K
Kz
zK
(b)
Figure 3 119911119870is the barycenter of 119870 and 119902
119890is to be the midpoint of the edge 119890
Kz
zK
z
Figure 4 119902119890is the midpoint of the edge 119890 and 119902
119878119894is the barycenter
of the face 119878119894
Here 119865ℎ(119905) = (119891
1(119905) 119891
2(119905) 119891
119873ℎ(119905))
119879 the mass matrix119872
ℎ= 119872
ℎ119894119895 = (120593
119894 120594
119895) is tridiagonal and both 119860
ℎ(119905) =
119860(119905 120593119894 120594
119895) and 119861
ℎ(119905 119904) = 119861(119905 119904 120593
119894 120594
119895) are positive
definitesIn order to describe features of the bilinear forms defined
in (11) we introduce some discrete norms on 119878ℎin the same
way as in [7]1003817100381710038171003817Vℎ
1003817100381710038171003817
2
0ℎ= (V
ℎ V
ℎ)0ℎ
= (119868lowast
ℎVℎ 119868
lowast
ℎVℎ)
1003816100381610038161003816Vℎ1003816100381610038161003816
2
1ℎ= sum
119909119894isin1198850
ℎ
sum
119909119895isinΠ(119894)
meas (119881119894) (
V119894minus V
119895
119889119894119895
)
2
1003817100381710038171003817Vℎ1003817100381710038171003817
2
1ℎ=1003817100381710038171003817Vℎ
1003817100381710038171003817
2
0ℎ+1003816100381610038161003816Vℎ
1003816100381610038161003816
2
1ℎ
1003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816Vℎ1003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816
2
= (Vℎ 119868
lowast
ℎVℎ)
(15)
where 119889119894119895
= 119889(119909119894 119909
119895) the distance between 119909
119894and 119909
119895
Obviously these norms are well defined for Vℎisin 119878
lowast
ℎas well
and Vℎ0ℎ
= |||Vℎ|||
Hereafter we state the equivalence of discrete norms sdot
0ℎand sdot
1ℎwith usual norms sdot and sdot
1on 119878
ℎ
respectively
Lemma 1 (see [7]) There exist two positive constants 1198620and
1198621such that for all V
ℎisin 119878
ℎ we have
1198620
1003817100381710038171003817Vℎ10038171003817100381710038170ℎ
le1003817100381710038171003817Vℎ
1003817100381710038171003817 le 1198621
1003817100381710038171003817Vℎ10038171003817100381710038170ℎ
forallVℎisin 119878
ℎ
1198620
1003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816Vℎ1003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816 le1003817100381710038171003817Vℎ
1003817100381710038171003817 le 1198621
1003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816Vℎ1003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816 forallVℎisin 119878
ℎ
1198620
1003817100381710038171003817Vℎ10038171003817100381710038171ℎ
le1003817100381710038171003817Vℎ
10038171003817100381710038171le 119862
1
1003817100381710038171003817Vℎ10038171003817100381710038171ℎ
forallVℎisin 119878
ℎ
(16)
Next we recall some properties of the bilinear forms (see[7 18])
Lemma 2 (see [7]) There exist two positive constants 119862 and119862
0such that for all 119906
ℎ V
ℎisin 119878
ℎ we have
119860 (119906ℎ 119868
lowast
ℎVℎ) le 119862
1003817100381710038171003817119906ℎ
10038171003817100381710038171
1003817100381710038171003817Vℎ10038171003817100381710038171 forall119906
ℎ V
ℎisin 119878
ℎ
119860 (Vℎ 119868
lowast
ℎVℎ) ge 119862
0
1003817100381710038171003817Vℎ1003817100381710038171003817
2
1 forallV
ℎisin 119878
ℎ
(17)
The following lemmas are proved in [3 7] which give thekey feature of the bilinear forms in the FVE method
Lemma 3 (see [3]) Assume that 120593 isin 1198821119901
0 Then one has
119860 (119905 120593 Vℎ) minus 119860 (119905 120593 119868
lowast
ℎVℎ)
= sum
119870isin120591ℎ
int120597119870
(119860 (119905) nabla120593 sdot n) (Vℎminus 119868
lowast
ℎVℎ) 119889119904
minus sum
119870isin120591ℎ
int119870
(nabla sdot 119860 (119905) nabla120593) (Vℎminus 119868
lowast
ℎVℎ) 119889119904 forallV
ℎisin 119878
ℎ
(18)
The aforementioned identity holds true when 119860(sdot sdot) is replacedby 119861(119905 119904 sdot sdot)
Lemma 4 (see [3]) Assume that 120593 isin 119878ℎ Then one has
119860 (119905 120593 120594) minus 119860 (119905 120593 119868lowast
ℎ120594) le 119862ℎ
100381610038161003816100381612059310038161003816100381610038161119901
100381610038161003816100381612059410038161003816100381610038161119902
(19)
Furthermore for 120593 isin 1198821119901
0cap119882
2119901 we have
119860 (119905 120593 120594) minus 119860 (119905 120593 119868lowast
ℎ120594) le 119862ℎ
100381710038171003817100381712059310038171003817100381710038172119901
100381710038171003817100381712059410038171003817100381710038171119902
(20)
Journal of Mathematics 5
3 Ritz-Volterra Projection andRelated Estimates
Following [7 19 20] we define the Ritz-Volterra projection119881ℎ(119905) 119867
1
0rarr 119878
ℎas follows
119860 (119905 119906 minus 119881ℎ119906 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 119906 (119904) minus 119881ℎ119906 (119904) 119868
lowast
ℎVℎ) 119889119904 = 0
119905 gt 0 forallVℎisin 119878
ℎ
(21)
This 119881ℎ(119905) is an elliptic projection with memory of 119906
into 119878lowast
ℎ It is easy to see that (21) is actually a system of
integral equations of Volterra type In fact if 119881ℎ(119905)119906 =
sum119873ℎ
119895=1120572119895(119905)120593
119895(119909) then (21) can be rewritten as
119860ℎ(119905) 120572 (119905) + int
119905
0
119861ℎ(119905 119904) 120572 (119904) 119889119904 = 119865
ℎ(119905) (22)
where 119860ℎ(119905) 119861
ℎ(119905 119904) are matrices and 120572(119905) 119865
ℎ(119905) are vectors
defined via
120572 (119905) = (1205721(119905) 120572
2(119905) 120572
119873ℎ(119905))
119879
119865ℎ119896(119905) = 119860 (119905 119906 120594
119896) + int
119905
0
119861 (119905 119904 119906 (119904) 120594119896) 119889119904
119896 = 1 2 119873ℎ
119860ℎ(119905) = 119860 (119905 120593
119896(119909) 120594
119897) 119861
ℎ(119905 119904) = 119861 (119905 119904 120593
119896(119909) 120594
119897)
(23)
From the positivity of 119860 (Lemma 2) and the linearity of(22) we see that the system (22) possesses a unique solution120572(119905) Consequently 119881
ℎ(119905)119906 in (21) is well defined
Set 120588 = 119906 minus 119881ℎ(119905)119906 The following lemma was proved in
[7] which shows the1198671 error estimate for 120588 and its temporalderivative
Lemma 5 (see [7]) Assume that 119863119899
119905119906 isin 119871
infin(119867
1
0cap 119867
2) for all
0 le 119899 le 119896 for some integer 119896 ge 0 Then for 119879 gt 0 fixed thereis a constant 119862 = 119862(119879 119896) gt 0 independent of ℎ and 119906 suchthat for all 0 le 119899 le 119896 and 0 lt 119905 lt 119879
1003817100381710038171003817120588 (119905)10038171003817100381710038171
le 119862ℎ(1199062 + int
119905
0
1199062119889119904)
1003817100381710038171003817119863119899
119905120588 (119905)
10038171003817100381710038171le 119862ℎ(
119899
sum
119894=0
10038171003817100381710038171003817119863
119894
119905119906100381710038171003817100381710038172
+ int
119905
0
1199062119889119904)
(24)
Now we establish 1198712 error estimate for 120588 and its temporalderivative which improves Theorem 22 in [7] This estimateis optimal with respect to the order
Lemma 6 Assume that for some integer 119896 ge 0 119863119899
119905119906 isin
119871infin(119867
1
0cap 119867
2) for all 0 le 119899 le 119896 Then for 119879 gt 0 fixed there is
a constant 119862 = 119862(119879 119896) gt 0 independent of ℎ and 119906 such thatfor all 0 le 119899 le 119896 and 0 lt 119905 lt 119879
1003817100381710038171003817120588 (119905)1003817100381710038171003817 le 119862ℎ
2(1199062 + int
119905
0
1199062119889119904)
1003817100381710038171003817119863119899
119905120588 (119905)
1003817100381710038171003817 le 119862ℎ2(
119899
sum
119894=0
10038171003817100381710038171003817119863
119894
119905119906100381710038171003817100381710038172
+ int
119905
0
1199062119889119904)
(25)
Proof The proof will proceed by duality argument Let 120595 isin
1198672(Ω) cap 119867
1
0(Ω) be the solution of
119860lowast(119905) 120595 = 120588 in Ω
120595 = 0 in 120597Ω
(26)
The solution 120595 isin 1198672(Ω) cap 119867
1
0(Ω) satisfies the following
regularity estimate1003817100381710038171003817120595
10038171003817100381710038172le 119862
10038171003817100381710038171205881003817100381710038171003817 (27)
Multiplying this equation by 120588 and then taking 1198712 innerprod-uct overΩ we obtain the following
10038171003817100381710038171205881003817100381710038171003817
2
= 119860 (119905 120588 120595)
= 119860 (119905 120588 120595 minus 119877ℎ120595) + 119860 (119905 120588 119877
ℎ120595 minus 119868
lowast
ℎ(119877
ℎ120595))
minus int
119905
0
119861 (119905 119904 120588 (119904) 119868lowast
ℎ119877ℎ120595 minus 119877
ℎ120595) 119889119904
minus int
119905
0
119861 (119905 119904 120588 (119904) 119877ℎ120595 minus 120595) 119889119904
minus int
119905
0
119861 (119905 119904 120588 (119904) 120595) 119889119904 = 1198681+ 119868
2+ 119868
3+ 119868
4+ 119868
5
(28)
We have
100381610038161003816100381611986811003816100381610038161003816 +
100381610038161003816100381611986841003816100381610038161003816 le 119862ℎ
2(1199062 + int
119905
0
1199062119889119904)1003817100381710038171003817120595
10038171003817100381710038172 (29)
Applying Lemma 4 we obtain
100381610038161003816100381611986821003816100381610038161003816 +
100381610038161003816100381611986831003816100381610038161003816 le 119862ℎ
2(1199062 + int
119905
0
1199062119889119904)1003817100381710038171003817120595
10038171003817100381710038172 (30)
Finally we have
100381610038161003816100381611986851003816100381610038161003816 le int
119905
0
(120588 (119904) 119861lowast(119905 119904) 120595) 119889119904 le 119862(int
119905
0
10038171003817100381710038171205881003817100381710038171003817 119889119904)
100381710038171003817100381712059510038171003817100381710038172 (31)
then we have
10038171003817100381710038171205881003817100381710038171003817 le 119862ℎ
2(1199062 + int
119905
0
1199062119889119904) + 119862(int
119905
0
10038171003817100381710038171205881003817100381710038171003817 119889119904) (32)
Finally an application of Gronwallrsquos lemma yields the firstestimate
The second inequality follows in a similar fashion
6 Journal of Mathematics
Lemma7 There exists a constant119862 independent of ℎ such that
100381710038171003817100381712058810038171003817100381710038170119901
+ ℎ100381710038171003817100381712058810038171003817100381710038171119901
le 119862ℎ2(1199062119901 + int
119905
0
1199062119901119889119904) (33)
Proof Let 120588119909be an arbitrary component of nabla120588 with 119901 and
119902 conjugate indices we have 120588119909119901
= sup(120588119909 120593) 120593 isin
Cinfin
0(Ω) 120593
119902= 1
For any such 120593 let 120595 be the solution of
119860lowast(119905 120595 V) = minus (120593
119909 V) forallV isin 119867
1
0(Ω)
120595 = 0 on 120597Ω
(34)
It follows from the regularity theory for the elliptic problemthat
100381710038171003817100381712059510038171003817100381710038171119902
le 119862119901
10038171003817100381710038171205931003817100381710038171003817119902
= 119862119901 (35)
We then have by application of (21) that
(120588119909 120593) = 119860 (119905 120588 120595) = 119860 (119905 120588 120595 minus 119877
ℎ120595)
+ 119860 (119905 120588 119877ℎ120595 minus 119868
lowast
ℎ(119877
ℎ120595))
+ int
119905
0
119861 (119905 119904 120588 (119904) 119868lowast
ℎ(119877
ℎ120595)) 119889119904
= 1198681+ 119868
2+ 119868
3
119860 (119905 120588 120595 minus 119877ℎ120595) = 119860 (119905 119877
ℎ119906 minus 119906 120595)
= minus ((119877ℎ119906 minus 119906)
119909 120593) le 119862ℎ1199062119901
(36)
Applying Lemma 4 we have
1198682= 119860 (119905 119906 119877
ℎ120595 minus 119868
lowast
ℎ(119877
ℎ120595)) minus 119860 (119905 119881
ℎ119906 119877
ℎ120595 minus 119868
lowast
ℎ(119877
ℎ120595))
le 119862ℎ1199062119901
(37)
Finally 1198683is estimated as follows
1198683= int
119905
0
119861 (119905 119904 120588 (119904) 119868lowast
ℎ(119877
ℎ120595)) 119889119904 le 119862
119901int
119905
0
100381710038171003817100381712058810038171003817100381710038171119901
119889119904 (38)
Combining these estimates we get
100381710038171003817100381712058810038171003817100381710038171119901
le 119862ℎ1199062119901 + 119862119901int
119905
0
100381710038171003817100381712058810038171003817100381710038171119901
119889119904 (39)
hence by Gronwallrsquos lemma
100381710038171003817100381712058810038171003817100381710038171119901
le 119862ℎ(1199062119901 + int
119905
0
1199062119901119889119904) (40)
The derivation of the error estimate in 119871119901 is similar to the casewhen 119901 = 2
4 Error Estimates forSemidiscrete Approximations
We split the error 119890(119905) = 119906(119905) minus 119906ℎ(119905) as follows
119890 (119905) = (119906 (119905) minus 119881ℎ119906 (119905)) + (119881
ℎ119906 (119905) minus 119906
ℎ(119905)) = 120588 + 120579 (41)
It is easy to see that 120579 = 119881ℎ119906(119905) minus 119906
ℎ(119905) isin 119878
ℎsatisfies an
error equation of the form
(120579119905 119868
lowast
ℎVℎ) + 119860 (119905 120579 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎVℎ) 119889119904
= minus (120588119905 119868
lowast
ℎVℎ) V
ℎisin 119878
ℎ
(42)
Since the estimates of 120588 are already known it is enoughto have estimates for 120579
We will prove a sequence of lemmas which lead to thefollowing result
Lemma8 There is a positive constant119862 independent of ℎ suchthat
|||120579 (119905)||| le 119862(|||120579 (0)|||2+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817 119889119904) (43)
Proof Since 120579 isin 119878ℎwe may take V
ℎ= 120579 in (42) to obtain
1
2
119889
119889119905|||120579 (119905)|||
2+ 119888120579
2
1le
10038171003817100381710038171205881199051003817100381710038171003817 120579 + 119862int
119905
0
12057911198891199041205791
le1003817100381710038171003817120588119905
1003817100381710038171003817 120579 +1
2119888120579
2
1+ 119862int
119905
0
1205792
1119889119904
(44)
and hence by integration and Lemma 1 we have
||120579 (119905)||2+ int
119905
0
1205792
1119889119904
le 119862(|||120579 (0)|||2+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817 120579 119889119904 + int
119905
0
int
119904
0
120579 (120591)2
1119889120591119889119904)
(45)
Gronwallrsquos lemma now implies the following
|||120579 (119905)|||2+ int
119905
0
1205792
1119889119904 le 119862(|||120579 (0)|||
2+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817 120579 119889119904)
le 119862|||120579 (0)|||2+1
2sup119904le119905
120579 (119904)2
+ (int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817 119889119904)
2
(46)
Since this holds for all isin 119869 we may conclude that
||120579 (119905)|| le 119862(|||120579 (0)||| + int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817 119889119904) (47)
Journal of Mathematics 7
Remark 9 If the initial value was chosen so that 1199060ℎminus 119906
0 le
119862ℎ2119906
02 then 120579(0) le 119906
0ℎminus119906
0+119881
ℎ1199060minus119906
0 le 119862ℎ
2119906
02
One can derive
|||120579 (119905)||| le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (48)
Lemma 10 There is a positive constant 119862 independent of ℎsuch that
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
119889119904 + 1205792
1le 119862(120579 (0)
2
1+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
2
119889119904) (49)
Proof Set Vℎ= 120579
119905in (42) to get
10038171003817100381710038171205791199051003817100381710038171003817
2
+1
2
119889
119889119905119860 (119905 120579 119868
lowast
ℎ120579)
= minus (120588119905 119868
lowast
ℎ120579119905) minus int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579119905(119905)) 119889119904
+1
2119860
119905(119905 120579 119868
lowast
ℎ120579)
+1
2[119860 (119905 120579
119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)]
le1
2
10038171003817100381710038171205881199051003817100381710038171003817
2
+1
2
1003816100381610038161003816
1003816100381610038161003816
10038161003816100381610038161205791199051003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816
2
+ 119860119905(119905 120579 119868
lowast
ℎ120579)
+1
2[119860 (119905 120579
119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)]
minus119889
119889119905int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579 (119905)) 119889119904
+ 119861 (119905 119905 120579 (119905) 119868lowast
ℎ120579 (119905)) + int
119905
0
119861119905(119905 119904 120579 (119904) 119868
lowast
ℎ120579 (119905)) 119889119904
(50)
Then
10038171003817100381710038171205791199051003817100381710038171003817
2
+119889
119889119905119860 (119905 120579 119868
lowast
ℎ120579)
le1003817100381710038171003817120588119905
1003817100381710038171003817
2
minus119889
119889119905int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579) 119889119904
+ 119862(1205792
1+ int
119905
0
120579 (119904)2
1119889119904)
+1
2[119860 (119905 120579
119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)]
(51)
In addition recall that
119860 (119905 119906ℎ 119868
lowast
ℎVℎ) minus 119860 (119905 V
ℎ 119868
lowast
ℎ119906ℎ) le 119862ℎ
1003817100381710038171003817119906ℎ
10038171003817100381710038171
1003817100381710038171003817Vℎ10038171003817100381710038171
forall119906ℎ V
ℎisin 119878
ℎ
(52)
then applying an inverse inequality and using kickbackargument we obtain
[119860 (119905 120579119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)] le 119862ℎ
100381710038171003817100381712057911990510038171003817100381710038171
1205791 le 1198621003817100381710038171003817120579119905
1003817100381710038171003817 1205791
le 1205761003817100381710038171003817120579119905
1003817100381710038171003817
2
+ 1198621205792
1
(53)
Combining these estimates we derive
10038171003817100381710038171205791199051003817100381710038171003817
2
+119889
119889119905119860 (119905 120579 119868
lowast
ℎ120579)
le1003817100381710038171003817120588119905
1003817100381710038171003817
2
minus119889
119889119905int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579) 119889119904
+ 119862(1205792
1+ int
119905
0
120579 (119904)2
1119889119904)
(54)
So after integration in time and using the weak coercivity of119860(119905 120579 119868
lowast
ℎ120579) we get
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
119889119904 + 1198880120579
2
1
le 1198880120579 (0)
2
1+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
2
119889119904
+ int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579) 119889119904 + 119862int
119905
0
120579 (119904)2
1119889119904
le 1198880120579 (0)
2
1+119888
2120579
2
1+ 119862(int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
2
+ 120579 (119904)2
1119889119904)
(55)
and by Gronwallrsquos lemma
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
119889119904 + 1198881205792
1le 119862(120579 (0)
2
1+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
2
119889119904) (56)
Remark 11 If 120579(0) = 0 then
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
119889119904 + 1198881205792
1le 119862ℎ
2(int
119905
0
1003817100381710038171003817119906119905
1003817100381710038171003817
2
2119889119904) (57)
Theorem 12 (error estimates in 1198712 and1198671-norms) Let 119906 119906
ℎ
be the solutions of (2) and (11) respectively Assume that 119906 119906119905isin
119871infin(119867
1
0cap 119867
2)
(a) Let 1199060ℎ
be chosen so that 1199060ℎ
minus 1199060 le 119862ℎ
2119906
02
Then for 119879 gt 0 fixed there is a constant 119862 = 119862(119879)
independent of ℎ such that for all 0 lt 119905 lt 119879
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905)
1003817100381710038171003817 le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (58)
(b) Let 1199060ℎ
be chosen so that 1199060ℎminus 119906
01
le 119862ℎ11990602
Then for 119879 gt 0 fixed there is a constant 119862 = 119862(119879)
independent of ℎ such that for all 0 lt 119905 lt 119879
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905))
10038171003817100381710038171le 119862ℎ(
10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (59)
We now prove error estimates for FVE approximations in119871119901 and119882
1119901-norms
8 Journal of Mathematics
Theorem 13 (error estimates in 119871119901 and 119882
1119901-norms) Let119906 119906
ℎbe the solutions of (2) and (11) respectively and 119906
0ℎ=
119881ℎ1199060 Assume that 119906 119906
119905isin 119871
infin(119867
1
0cap 119882
2119901) For ℎ sufficiently
small we have
1003817100381710038171003817119906 minus 119906ℎ
10038171003817100381710038170119901le 119862ℎ
2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
1003817100381710038171003817119906 minus 119906ℎ
10038171003817100381710038171119901le 119862ℎ(
10038171003817100381710038171199060
10038171003817100381710038172+ 1199062119901 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
(60)
Proof If 2 le 119901 lt infin by the following Sobolev embeddinginequality
1205790119901 le 1198621205791 (61)
then the first desired estimate follows from Lemmas 7 and 10Given 120593 isin Cinfin
0(Ω) find 120595 isin 119867
1
0(Ω) such that
119860(119905)lowast120595 = minus120593
119909 in Ω
120595 = 0 on 120597Ω
100381710038171003817100381712059510038171003817100381710038171119902
le100381710038171003817100381712059310038171003817100381710038170119902
(62)
We have
((119906 minus 119906ℎ)119909 120593) = 119860 (119905 119906 minus 119906
ℎ 120595) = 119860 (119905 119906 minus 119906
ℎ 120595 minus 119877
ℎ120595)
+ 119860 (119905 119906 minus 119906ℎ 119877
ℎ120595 minus 119868
lowast
ℎ119877ℎ120595)
minus int
119905
0
119861 (119905 119904 (119906 minus 119906ℎ) (119904) 119868
lowast
ℎ119877ℎ120595) 119889119904
minus ((119906 minus 119906ℎ)119905 119868
lowast
ℎ119877ℎ120595)
= 1198681+ 119868
2+ 119868
3+ 119868
4
100381610038161003816100381611986811003816100381610038161003816 le
1003816100381610038161003816119860 (119905 119906 minus 119877ℎ119906 120595)
1003816100381610038161003816 le 1198621003817100381710038171003817119906 minus 119877
ℎ11990610038171003817100381710038171119901
100381710038171003817100381712059510038171003817100381710038171119902
le 119862ℎ11990621199011003817100381710038171003817120595
10038171003817100381710038171119902
(63)
By Lemma 4
100381610038161003816100381611986821003816100381610038161003816 le 119860 (119905 119906 minus 119906
ℎ 119877
ℎ120595 minus 119868
lowast
ℎ119877ℎ120595)
le 119862ℎ (1003816100381610038161003816119906 minus 119906
ℎ
10038161003816100381610038161119901+ |119906|2119901)
100381710038171003817100381712059510038171003817100381710038171119902
100381610038161003816100381611986831003816100381610038161003816 le int
119905
0
1003817100381710038171003817119906 minus 119906ℎ
100381710038171003817100381711199011198891199041003817100381710038171003817120595
10038171003817100381710038171119902
100381610038161003816100381611986841003816100381610038161003816 le (
1003817100381710038171003817119906 minus 119906ℎ
1003817100381710038171003817)1003817100381710038171003817120595
1003817100381710038171003817 le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
100381710038171003817100381712059510038171003817100381710038171119902
(64)
where we have used the fact 120595 le 1205951119903 119903 gt 1 Combining
these estimates we get
1003816100381610038161003816((119906 minus 119906ℎ)119909 120593)
1003816100381610038161003816 le 119862ℎ(10038171003817100381710038171199060
10038171003817100381710038172+ 1199062119901 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
100381710038171003817100381712059510038171003817100381710038171119902
1003817100381710038171003817(119906 minus 119906ℎ)119909
10038171003817100381710038170119901= sup
((119906 minus 119906ℎ)119909 120593)
100381710038171003817100381712059310038171003817100381710038170119902
le 119862ℎ1003816100381610038161003816119906 minus 119906
ℎ
10038161003816100381610038161119901
+ 119862ℎ(10038171003817100381710038171199060
10038171003817100381710038172+ 1199062119901 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
(65)
Hence using the Poincare inequality we have for ℎ sufficientlysmall
1003817100381710038171003817119906 minus 119906ℎ
10038171003817100381710038171119901le 119862ℎ(
10038171003817100381710038171199060
10038171003817100381710038172+ 1199062119901 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (66)
We compare the relationship between covolume solutionand the Galerkin finite element solution
Corollary 14 Let ℎbe the finite element solution to (2) that
is
(ℎ119905 V
ℎ) + 119860 (119905
ℎ V
ℎ)
+ int
119905
0
119861 (119905 119904 ℎ(119904) V
ℎ) 119889119904 = (119891 V
ℎ) V
ℎisin 119878
ℎ
ℎ(0) = 119877
ℎ1199060
(67)
For ℎ sufficiently small we have
1003817100381710038171003817(ℎminus 119906
ℎ)10038171003817100381710038171119901
le 119862(
ℎ1003817100381710038171003817119906 minus 119906
ℎ
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus 119906
ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817
+int
119905
0
(1003817100381710038171003817(119906 minus 119906
ℎ) (119904)
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus
ℎ) (119904)
10038171003817100381710038171119901) 119889119904
)
le 119862 (119906) ℎ
(68)
Proof By (2) and (67)
((ℎminus 119906)
119905 V
ℎ) + 119860 (119905
ℎminus 119906 V
ℎ)
+ int
119905
0
119861 (119905 119904 (ℎminus 119906) (119904) V
ℎ) 119889119904 = 0 V
ℎisin 119878
ℎ
(69)
Consider the following auxiliary problem For any such 120593 let120595 be the solution of the following
119860(119905)lowast120595 = minus120593
119909 in Ω
120595 = 0 on 120597Ω
(70)
Journal of Mathematics 9
with1003817100381710038171003817120595
10038171003817100381710038171119902le100381710038171003817100381712059310038171003817100381710038170119902
((ℎminus 119906
ℎ)119909 120593)
= 119860 (119905 ℎminus 119906
ℎ 120595)
= 119860 (119905 ℎminus 119906
ℎ 120595 minus 119877
ℎ120595) + 119860 (119905 119906 minus 119906
ℎ 119877
ℎ120595)
minus 119860 (119905 119906 minus 119906ℎ 119868
lowast
ℎ119877ℎ120595) minus ((119906 minus 119906
ℎ)119905 119868
lowast
ℎ119877ℎ120595)
minus int
119905
0
119861 (119905 119904 (119906 minus 119906ℎ) (119904) 119868
lowast
ℎ119877ℎ120595) 119889119904
+ 119860 (119905 ℎminus 119906 119877
ℎ120595)
= [119860 (119905 119906 minus 119906ℎ 119877
ℎ120595) minus 119860 (119905 119906 minus 119906
ℎ 119868
lowast
ℎ119877ℎ120595)]
minus ((119906 minus 119906ℎ)119905 119868
lowast
ℎ119877ℎ120595) minus ((
ℎminus 119906)
119905 119877
ℎ120595)
minus int
119905
0
119861 (119905 119904 (119906 minus 119906ℎ) (119904) 119868
lowast
ℎ119877ℎ120595) 119889119904
minus int
119905
0
119861 (119905 119904 (ℎminus 119906) (119904) 119877
ℎ120595) 119889119904
= 1198681+ 119868
2+ 119868
3
(71)
On the other hand10038161003816100381610038161198681
1003816100381610038161003816 le 119862ℎ1003817100381710038171003817119906 minus 119906
ℎ
10038171003817100381710038171119901
100381710038171003817100381712059510038171003817100381710038171119902
100381610038161003816100381611986821003816100381610038161003816 le 119862 (
1003817100381710038171003817(119906 minus 119906ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817)1003817100381710038171003817120595
1003817100381710038171003817
le 119862 (1003817100381710038171003817(119906 minus 119906
ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817)1003817100381710038171003817120595
10038171003817100381710038171119902
(72)
where we have used the fact 120595 le 1205951119903 119903 gt 1
100381610038161003816100381611986831003816100381610038161003816 le int
119905
0
(1003817100381710038171003817(119906 minus 119906
ℎ) (119904)
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus
ℎ) (119904)
10038171003817100381710038171119901) 119889119904
100381710038171003817100381712059510038171003817100381710038171119902
1003817100381710038171003817(ℎminus 119906
ℎ)119909
10038171003817100381710038170119901
= sup120593isinCinfin0
((ℎminus 119906
ℎ)119909 120593)
100381710038171003817100381712059310038171003817100381710038170119902
le 119862(
ℎ1003817100381710038171003817119906 minus 119906
ℎ
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus 119906
ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817
+int
119905
0
(1003817100381710038171003817(119906 minus 119906
ℎ) (119904)
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus
ℎ) (119904)
10038171003817100381710038171119901) 119889119904
)
(73)
We deduce the result from the known finite element esti-mates
Remark 15 In order to estimate (119906 minus 119906ℎ)119905 by differentiating
(42) with respect to 119905 we obtain
(120579119905119905 119868
lowast
ℎVℎ) + 119860 (119905 120579
119905 119868
lowast
ℎVℎ) + 119860
119905(119905 120579
119905 119868
lowast
ℎVℎ)
+ 119861 (119905 119905 120579 119868lowast
ℎVℎ) + int
119905
0
119861119905(119905 119904 120579 (119904) 119868
lowast
ℎVℎ) 119889119904
= minus (120588119905119905 119868
lowast
ℎVℎ)
(74)
Setting Vℎ= 120579
119905 we obtain
1
2
119889
119889119905
1003816100381610038161003816
1003816100381610038161003816
10038161003816100381610038161205791199051003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816
2
+ 1198881003817100381710038171003817120579119905
1003817100381710038171003817
2
1le1003817100381710038171003817120588119905119905
1003817100381710038171003817
10038171003817100381710038171205791199051003817100381710038171003817
+1
21198881003817100381710038171003817120579119905
1003817100381710038171003817
2
1+ 119862120579
2
1+ int
119905
0
1205792
1119889119904
le1003817100381710038171003817120588119905119905
1003817100381710038171003817
10038171003817100381710038171205791199051003817100381710038171003817 +
1
21198881003817100381710038171003817120579119905
1003817100381710038171003817
2
1+ 119862int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
1119889119904
(75)
Using kickback argument integrating and applying Gron-wallrsquos lemma we deduce
10038171003817100381710038171205791199051003817100381710038171003817 le 119862(
1003817100381710038171003817120579119905 (0)1003817100381710038171003817 + int
119905
0
100381710038171003817100381712058811990511990510038171003817100381710038171119889119904)
le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+10038171003817100381710038171199061
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904)
(76)
5 The Lumped Mass Finite VolumeElement Method
In this section we restrict our study to the 2D case A simpleway to define the lumped mass scheme [21] is to replace themass matrix 119872
ℎin (14) by the diagonal matrix 119872
ℎobtained
by taking for its diagonal elements the numbers 119872ℎ119894119894
=
sum119873ℎ
119895=1119872
ℎ119894119895or by lumping all masses in one row into the
diagonal entryThismakes the inversion of thematrix in frontof1205721015840
(119905) a trivialityWewill therefore study thematrix problem
119872ℎ1205721015840(119905) + 119860
ℎ(119905) 120572 (119905) + int
119905
0
119861ℎ(119905 119904) 120572 (119904) 119889119904 = 119865
ℎ(119905) (77)
We know that the lumped mass method defined by (77)above is equivalent to
(119868lowast
ℎ119906ℎ119905 119868
lowast
ℎVℎ) + 119860 (119905 119906
ℎ 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 119906ℎ(119904) 119868
lowast
ℎVℎ) 119889119904
= (119891 119868lowast
ℎVℎ) V
ℎisin 119878
ℎ
(78)
Our alternative interpretation of this procedure will beto think of (77) as being obtained by evaluating the firstterm in (78) by numerical quadrature Let 119870 be a triangle ofthe triangulation 119879
ℎ let 119909
119895 119895 = 1 2 3 be its vertices and
consider the quadrature formula
119876119870ℎ
(119891) =1
3area119870
3
sum
119895=1
119891 (119909119895) ≃ int
119870
119891119889119909 (79)
We may then define the associated bilinear form in 119878ℎtimes
119878lowast
ℎ using the quadrature scheme by the following
(Vℎ 120578
ℎ)ℎ= sum
119870isin119879ℎ
119876119870ℎ
(Vℎ120578ℎ) = sum
119909119894isin119873119886
ℎ
Vℎ(119909
119894) 120578
ℎ(119909
119894)10038161003816100381610038161003816119881119909119894
10038161003816100381610038161003816
forallVℎisin 119878
ℎ 120578
ℎisin 119878
lowast
ℎ
(80)
10 Journal of Mathematics
We note that Vℎ2
ℎ= (V
ℎ 119868
lowast
ℎVℎ)ℎis a norm in 119878
ℎwhich is
equivalent to the 1198712-norm uniformly in ℎ that is there existtwo positive constants 119862
1and 119862
2such that for all V
ℎisin 119878
ℎ we
have
1198620
1003817100381710038171003817Vℎ1003817100381710038171003817 le
1003817100381710038171003817Vℎ1003817100381710038171003817ℎ
le 1198621
1003817100381710038171003817Vℎ1003817100381710038171003817 forallV
ℎisin 119878
ℎ (81)
We note that the aforementioned definition (Vℎ 120578
ℎ)ℎmay
be used also for 120578ℎisin 119878
ℎand that (V
ℎ 119908
ℎ)ℎ= (V
ℎ 119868
lowast
ℎ119908
ℎ)ℎfor
Vℎ 119908
ℎisin 119878
ℎ
The lumpedmass method defined by (78) is equivalent to
(119906ℎ119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 119906
ℎ 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 119906ℎ(119904) 119868
lowast
ℎVℎ) 119889119904
= (119891 119868lowast
ℎVℎ) V
ℎisin 119878
ℎ
(82)
We introduce the quadrature error
120576ℎ(V
ℎ 119908
ℎ) = (V
ℎ 119908
ℎ)ℎminus (V
ℎ 119908
ℎ) (83)
Lemma 16 (see [21]) Let Vℎ 119908
ℎisin 119878
ℎ Then
1003816100381610038161003816120576ℎ (Vℎ 119908ℎ)1003816100381610038161003816 le 119862ℎ
2 1003817100381710038171003817nablaVℎ1003817100381710038171003817
1003817100381710038171003817nabla119908ℎ
1003817100381710038171003817 (84)
Theorem 17 Let 119906ℎand 119906 be the solutions of (82) and (2)
respectively and assume 119906ℎ(0) = 119877
ℎ1199060 Then we have for the
error in the lumped mass semidiscrete method for 119905 ge 0 thefollowing
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905)
1003817100381710038171003817 le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ 1199062 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (85)
Proof In order to estimate 120579 we write
(120579119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 120579 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎVℎ) 119889119904
= (119906ℎ119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 119906
ℎ 119868
lowast
ℎVℎ)
+ int
119905
0
119861 (119905 119904 119906ℎ(119904) 119868
lowast
ℎVℎ) 119889119904
minus ((119881ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus 119860 (119905 119881
ℎ119906 119868
lowast
ℎVℎ)
minus int
119905
0
119861 (119905 119904 119881ℎ119906 (119904) 119868
lowast
ℎVℎ) 119889119904
= (119891 119868lowast
ℎVℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus 119860 (119905 119906 119868
lowast
ℎVℎ)
minus int
119905
0
119861 (119905 119904 119906 (119904) 119868lowast
ℎVℎ)
= (119906119905 119868
lowast
ℎVℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)ℎ
= minus (120588119905 119868
lowast
ℎVℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)ℎ+ ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
(86)
We rewrite
((119881ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
= ((119881ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus ((119881
ℎ119906)
119905 V
ℎ)
+ ((119881ℎ119906)
119905 V
ℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
= 120576ℎ((119881
ℎ119906)
119905 V
ℎ) + ((119881
ℎ119906)
119905 V
ℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
(120579119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 120579 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎVℎ) 119889119904
= minus (120588119905 119868
lowast
ℎVℎ) + 120576
ℎ((119881
ℎ119906)
119905 V
ℎ)
+ ((119881ℎ119906)
119905 V
ℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
(87)
Setting Vℎ= 120579 in (87) we obtain
1
2
119889
119889119905120579
2
ℎ+ 119888
01205792
1
le1003817100381710038171003817120588119905
1003817100381710038171003817 120579 +1
21198880120579
2
1+ 119862int
119905
0
1205792
1119889119904
+ 120576ℎ((119881
ℎ119906)
119905 120579) + ((119881
ℎ119906)
119905 120579) minus ((119881
ℎ119906)
119905 119868
lowast
ℎ120579)
(88)
Using Lemma 16 and the inverse estimate we get1003816100381610038161003816120576ℎ (119881ℎ
119906119905 120579)
1003816100381610038161003816 le 119862ℎ2 1003817100381710038171003817nabla(119881ℎ
119906)119905
1003817100381710038171003817 nabla120579
le 119862ℎ2 1003817100381710038171003817nabla119906119905
1003817100381710038171003817 nabla120579
le 119862ℎ1003817100381710038171003817nabla119906119905
1003817100381710038171003817 120579
(89)
we have1003816100381610038161003816((119881ℎ
119906)119905 120579) minus ((119881
ℎ119906)
119905 119868
lowast
ℎ120579)1003816100381610038161003816 le 119862ℎ
1003817100381710038171003817nabla119906119905
1003817100381710038171003817 120579 (90)
Using Youngrsquos inequality and Gronwallrsquos lemma to eliminate120579
1on the right-hand side and using integration in 119905 we get
the result
1
2
119889
119889119905120579
2
ℎ+ 119888
0 120579 le1003817100381710038171003817120588119905
1003817100381710038171003817 120579 + 119862ℎ1003817100381710038171003817nabla119906119905
1003817100381710038171003817 120579 (91)
Using Youngrsquos inequality to eliminate 120579 on the right handside it becomes
Using integration in 119905 we get the result
We will now show that the 1198671-norm error bound of
theorem remains valid for the lumped mass method (82)
Theorem 18 Let 119906ℎand 119906 be the solutions of (82) and (2)
respectively and assume
119906ℎ(0) = 119877
ℎ1199060
10038171003817100381710038171199061ℎ(0) minus 119906
1
1003817100381710038171003817 le 119862ℎ210038171003817100381710038171199061
10038171003817100381710038172 (92)
Then we have for the error in the lumped mass semidiscretemethod for 119905 ge 0 the following
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905)
10038171003817100381710038171le 119862ℎ
2(10038171003817100381710038171199060
10038171003817100381710038172+10038171003817100381710038171199061
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904)
(93)
Journal of Mathematics 11
Proof Setting Vℎ= 120579
119905in (87) we obtain
10038171003817100381710038171205791199051003817100381710038171003817
2
ℎ+1
2
119889
119889119905119860 (119905 120579 119868
lowast
ℎ120579)
=1
2119860
119905(119905 120579 119868
lowast
ℎ120579) +
1
2[119860 (119905 120579
119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)]
119861 (119905 119905 120579 (119905) 119868lowast
ℎ120579 (119905)) + int
119905
0
119861119905(119905 119904 120579 (119904) 119868
lowast
ℎ120579 (119905)) 119889119904
minus119889
119889119905int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579 (119905)) 119889119904 minus (120588
119905 119868
lowast
ℎ120579119905)
minus 120576ℎ((119881
ℎ119906)
119905 120579
119905) + ((119881
ℎ119906)
119905 120579) minus ((119881
ℎ119906)
119905 119868
lowast
ℎ120579)
(94)
It follows thus that using integration in 119905 and Gronwallrsquoslemma we have
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
ℎ+ 120579
2
1le 119862nabla120579 (0)
2+ 119862int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
10038171003817100381710038171205791199051003817100381710038171003817 119889119904
+ 119862ℎ2int
119905
0
1003817100381710038171003817119906119905
1003817100381710038171003817
2
1119889119904
(95)
6 Full Discretization
Let 120597119880119899= (119880
119899minus119880
119899minus1)119896 be the backward difference quotient
of 119880119899 assume that 119860ℎ
= 119875ℎ119860 is a discrete analogue of 119860
(similarly 119861ℎ
= 119875ℎ119861) where 119875
ℎ 119871
2(Ω) rarr 119878
lowast
ℎthe 119871
2
projection is defined by
(119875ℎV 119868lowast
ℎVℎ) = (V 119868lowast
ℎVℎ) V isin 119871
2(Ω) V
ℎisin 119878
ℎ (96)
In order to define fully discrete approximation of (11) wediscretize the time by taking 119905
119899= 119899119896 119896 gt 0 119899 = 1 2 and
use the numerical quadrature
int
119905119899minus12
0
119892 (119904) 119889119904 asymp
119899
sum
119896=1
120596119899119896119892 (119905
119896minus12) 119905
119899minus12= (119899 minus
1
2) 119896
(97)
Here 120596119899119896 are the integrationweights andwe assume that
the following error estimate is valid
119902119899(119892) = int
119905119899minus12
0
119892 (119904) 119889119904minus
119899
sum
119896=1
120596119899119896119892 (119905
119896minus12)
le 1198621198962int
119905119899
0
(10038161003816100381610038161003816119892101584010038161003816100381610038161003816+100381610038161003816100381610038161198921015840101584010038161003816100381610038161003816) 119889119904
(98)
Now define our complete discrete FVE approximation of(11) by the following find 119880
119899isin 119878
ℎfor 119899 = 1 2 such that
for all Vℎisin 119878
ℎ
(120597119880119899 119868
lowast
ℎVℎ) + 119860 (119905
119899minus12 119880
119899minus12 119868
lowast
ℎVℎ)
+
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12 119880
119896minus12 119868
lowast
ℎVℎ)
= (119891119899minus12
119868lowast
ℎVℎ)
1198800 in 119878
ℎ
(99)
where 119880119899minus12= (119880
119899+ 119880
119899minus1)2
Theorem 19 Let 119906(119905) and 119880119899 be the solutions of problem (2)
and its complete discrete scheme (99) respectively Then forany 119879 gt 0 there exists a positive constant 119862 = 119862(119879) gt 0independent of ℎ such that for 0 lt 119905
119899le 119879
1003817100381710038171003817119906 (119905119899) minus 1198801198991003817100381710038171003817
le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905119899
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
+ 1198621198962(int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905119905
1003817100381710038171003817) 119889119904)
(100)
Proof Let us split the error into two parts 119906(119905119899) minus 119880
119899= 120588
119899+
120579119899 where 120588
119899= 119906(119905
119899)minus119881
ℎ119906(119905
119899) and 120579119899 = 119881
ℎ119906(119905
119899)minus119880
119899 and let119882 = 119881
ℎ119906(119905) isin 119878
ℎbe the Ritz-Volterra projection of 119906 Then
from (2) and (99) we have for all Vℎisin 119878
ℎthe following
(120597120579119899 119868
lowast
ℎVℎ) + 119860 (119905
119899minus12 120579
119899minus12 119868
lowast
ℎVℎ)
+
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12 120579
119896minus12 119868
lowast
ℎVℎ)
= minus (119903119899 119868
lowast
ℎVℎ) forallV
ℎisin 119878
ℎ
(101)
where
119903119899= 119903
1
119899+ 119903
2
119899+ 119903
3
119899+ 119903
4
119899
1199031
119899= 120597120588
119899
1199032
119899= 120597119906 (119905
119899) minus 119906
119905(119905
119899minus12)
1199033
119899= 119860(119905
119899minus12(119906 (119905
119899) + 119906 (119905
119899minus1))
2minus 119906 (119905
119899minus12))
1199034
119899= 119902
119899(119861
ℎ119882)
=
119899
sum
119896=1
120596119899119896119861ℎ(119905
119899minus12 119905
119896minus12119882
119896minus12 119868
lowast
ℎVℎ)
minus int
119905119899minus12
0
119861 (119905119899 119904119882 (119904) 119868
lowast
ℎVℎ) 119889119904
(102)
In fact by Taylor expansion
119906119899+1
= 119906119899+ 119896119906
1015840(119905
119899) + int
119905119899+1
119905119899
11990610158401015840(119904) (119905
119899+1minus 119904) 119889119904
= 119906119899+ 119896119906
1015840(119905
119899) +
1198962
211990610158401015840(119905
119899) +
1198963
6119906(3)
(119905119899)
+1
6int
119905119899+1
119905119899
119906(4)
(119904) (119905119899+1
minus 119904)3
119889119904
(103)
12 Journal of Mathematics
we have100381710038171003817100381710038171199031
119899
10038171003817100381710038171003817=
10038171003817100381710038171003817120597120588
11989910038171003817100381710038171003817le
1
119896int
119905119899
119905119899minus1
10038171003817100381710038171205881199051003817100381710038171003817 119889119904 le 119862
ℎ2
119896int
119905119899
119905119899minus1
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
100381710038171003817100381710038171199032
119899
10038171003817100381710038171003817=
10038171003817100381710038171003817120597119906 (119905
119899) minus 119906
119905(119905
119899minus12)10038171003817100381710038171003817
=1
119896
100381710038171003817100381710038171003817100381710038171003817
int
119905119899
119905119899minus1
(119906119905(119904) minus 119906
119905(119905
119899minus12)) 119889119904
100381710038171003817100381710038171003817100381710038171003817
le 119862119896int
119905119899
119905119899minus1
10038171003817100381710038171003817119906(3)
(119904)10038171003817100381710038171003817119889119904
100381710038171003817100381710038171199033
119899
10038171003817100381710038171003817=
100381710038171003817100381710038171003817100381710038171003817
119860(119905119899minus12
119906 (119905
119899) + 119906 (119905
119899minus1)
2minus 119906 (119905
119899minus12) 119868
lowast
ℎVℎ)
100381710038171003817100381710038171003817100381710038171003817
le 119862119896int
119905119899
119905119899minus1
1003817100381710038171003817119860119906119905119905(119904)
1003817100381710038171003817 119889119904 le 119862119896int
119905119899
119905119899minus1
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
(104)
In addition the quadrature error satisfies100381710038171003817100381710038171199034
119899
10038171003817100381710038171003817= 119902
119899minus12(119861
ℎ119882)
=
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12119882
119896minus12 119868
lowast
ℎVℎ)
minus int
119905119899minus12
0
119861 (119905119899 119904119882 (119904) 119868
lowast
ℎVℎ) 119889119904
le 1198621198962int
119905119899
0
1003817100381710038171003817(119861ℎ119882)
119904119904
1003817100381710038171003817 119889119904
le 1198621198962int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172) 119889119904
119896
119873
sum
119899=1
10038171003817100381710038171199031198991003817100381710038171003817 le 119862ℎ
2int
119905119899
0
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
+ 1198621198962int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172+10038171003817100381710038171003817119906(3)10038171003817100381710038171003817
) 119889119904
(105)
Taking Vℎ= 120579
119899minus12 in (101) and noting that (120597120579119899 119868lowastℎ120579119899minus12
) =
(12)120597|||120579119899|||
2 there is1003816100381610038161003816
1003816100381610038161003816
10038161003816100381610038161205791198991003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816
2
minus10038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus110038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
+ 211989611988810038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus1210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
1
le 1198621198962
119899
sum
119896=1
10038171003817100381710038171003817120579119896minus12100381710038171003817100381710038171
10038171003817100381710038171003817120579119899minus12100381710038171003817100381710038171
+ 1198621198961003817100381710038171003817119903119899
1003817100381710038171003817
10038171003817100381710038171003817120579119899minus1210038171003817100381710038171003817
le11989611988810038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus1210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
1+ 119862119896
2
119899
sum
119896=1
10038171003817100381710038171003817120579119896minus1210038171003817100381710038171003817
2
1+ 119862119896
10038171003817100381710038171199031198991003817100381710038171003817
10038171003817100381710038171003817120579119899minus1210038171003817100381710038171003817
(106)
Summing from 119899 = 1 to 119873 and then after cancelling thecommon factor and using Gronwallrsquos lemma we obtain
10038161003816100381610038161003816
10038161003816100381610038161003816
1003816100381610038161003816100381612057911987310038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
le 11986210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579010038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
+ 119862119896
119873
sum
119896=1
10038171003817100381710038171199031198991003817100381710038171003817 (
1003817100381710038171003817100381712057911989610038171003817100381710038171003817
+10038171003817100381710038171003817120579119896minus1210038171003817100381710038171003817
) (107)
and then
10038161003816100381610038161003816
10038161003816100381610038161003816
1003816100381610038161003816100381612057911987310038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816le 119862
10038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579010038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816+ 119862119896
119873
sum
119899=1
10038171003817100381710038171199031198991003817100381710038171003817
(108)
the theorem follows from the estimates of 120588119899 and 119903119899
References
[1] Z Q Cai ldquoOn the finite volume element methodrdquo NumerischeMathematik vol 58 no 7 pp 713ndash735 1991
[2] S H Chou and D Y Kwak ldquoAnalysis and convergence of aMAC-like scheme for the generalized Stokes problemrdquo Numer-ical Methods for Partial Differential Equations vol 13 no 2 pp147ndash162 1997
[3] P Chatzipantelidis ldquoA finite volume method based on theCrouzeix-Raviart element for elliptic PDErsquos in two dimensionsrdquoNumerische Mathematik vol 82 no 3 pp 409ndash432 1999
[4] P Chatzipantelidis ldquoFinite volumemethods for elliptic PDErsquos anew approachrdquo Mathematical Modelling and Numerical Analy-sis vol 36 no 2 pp 307ndash324 2002
[5] P Chatzipantelidis R D Lazarov and V Thomee ldquoErrorestimates for a finite volume element method for parabolicequations in convex polygonal domainsrdquoNumericalMethods forPartial Differential Equations vol 20 no 5 pp 650ndash674 2004
[6] R E Ewing R D Lazarov and Y Lin ldquoFinite volume elementapproximations of nonlocal in time one-dimensional flows inporous mediardquo Computing vol 64 no 2 pp 157ndash182 2000
[7] R Ewing R Lazarov and Y Lin ldquoFinite volume elementapproximations of nonlocal reactive flows in porous mediardquoNumericalMethods for Partial Differential Equations vol 16 no3 pp 285ndash311 2000
[8] R E Ewing T Lin andY Lin ldquoOn the accuracy of the finite vol-ume element method based on piecewise linear polynomialsrdquoSIAM Journal on Numerical Analysis vol 39 no 6 pp 1865ndash1888 2002
[9] R K Sinha and J Geiser ldquoError estimates for finite volumeelement methods for convection-diffusion-reaction equationsrdquoApplied Numerical Mathematics vol 57 no 1 pp 59ndash72 2007
[10] S H Chou ldquoAnalysis and convergence of a covolume methodfor the generalized Stokes problemrdquo Mathematics of Computa-tion vol 66 no 217 pp 85ndash104 1997
[11] M Berggren ldquoA vertex-centered dual discontinuous Galerkinmethodrdquo Journal of Computational and Applied Mathematicsvol 192 no 1 pp 175ndash181 2006
[12] S H Chou and D Y Kwak ldquoMultigrid algorithms for a vertex-centered covolume method for elliptic problemsrdquo NumerischeMathematik vol 90 no 3 pp 441ndash458 2002
[13] R Eymard T Gallouet and R Herbin Finite Volume MethodsHandbook of Numerical Analysis North-Holland AmsterdamThe Netherlands 2000
[14] V R Voller Basic Control Volume Finite Element Methods forFluids and Solids World Scientific Publishing 2009
[15] J Huang and S Xi ldquoOn the finite volume element method forgeneral self-adjoint elliptic problemsrdquo SIAM Journal on Numer-ical Analysis vol 35 no 5 pp 1762ndash1774 1998
[16] X Ma S Shu and A Zhou ldquoSymmetric finite volume discreti-zations for parabolic problemsrdquo Computer Methods in AppliedMechanics and Engineering vol 192 no 39-40 pp 4467ndash44852003
[17] R D Lazarov and S Z Tomov ldquoAdaptive finite volume elementmethod for convection-diffusion-reaction problems in 3-Drdquo inScientific Computing and Applications vol 7 of Advances inComputation Theory and Practice pp 91ndash106 Nova SciencePublishers Huntington NY USA 2001
[18] I DMishevFinite volume and finite volume elementmethods fornon-symmetric problems [PhD thesis] Texas AampM University1997 Technical Report ISC-96-04-MATH
Journal of Mathematics 13
[19] C Chen and T Shih Finite Element Methods for Integrodifferen-tial Equations World Scientific Publishing Singapore 1998
[20] Y P Lin V Thomee and L B Wahlbin ldquoRitz-Volterra pro-jections to finite-element spaces and applications to integrod-ifferential and related equationsrdquo SIAM Journal on NumericalAnalysis vol 28 no 4 pp 1047ndash1070 1991
[21] VThomeeGalerkin Finite Element Methods for Parabolic Prob-lems Springer Series in Computational Mathematics SpringerNew York NY USA 2006
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical Problems in Engineering
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Differential EquationsInternational Journal of
Volume 2014
Applied MathematicsJournal of
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Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical PhysicsAdvances in
Complex AnalysisJournal of
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OptimizationJournal of
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CombinatoricsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
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Operations ResearchAdvances in
Journal of
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Function Spaces
Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of Mathematics and Mathematical Sciences
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The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Algebra
Discrete Dynamics in Nature and Society
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Decision SciencesAdvances in
Discrete MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
Volume 2014 Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Stochastic AnalysisInternational Journal of
2 Journal of Mathematics
two-dimensional parabolic integrodifferential equations andhave obtained an optimal-order estimate in the 1198712-normTheregularity required on the exact solution 119906 is 1198823119901 for 119901 gt 1
which is higher when compared to that for finite elementmethods
The aim of this paper is to study the convergence of FVEdiscretization for a nonself-adjoint parabolic integrodifferen-tial problem (1) Both spatially discrete scheme and discrete-in-time scheme are analyzed and optimal error estimates in1198712 and 119867
1 norms are proved using only energy method Wealso explore and generalize that idea to develop the lumpedmass modification and 119871
119901 estimates 2 le 119901 lt infin Ouranalysis avoids the use of semigroup theory and the regularityrequirement on the solution is the same of that of finiteelement method Furthermore based on the Crank-Nicolsonmethod the fully discrete scheme is analyzed and the relatedoptimal error estimates are established
This paper is organized as follows In Section 2 we intro-duce some notations and present some preliminary materialsto be used later The Ritz-Volterra projection to finite volumeelement spaces is introduced and related estimates are carriedout in Section 3 In Section 4 we estimate the error of thefinite volume element approximations derived in the previoussection In Section 5 the lumped mass is presented andoptimal estimates in 119871
2 and 1198671 norms are obtained Finally
the Crank-Nicolson scheme is studied in Section 6
2 Finite Volume Element Scheme
In this section we introduce some material which will beused repeatedly hareafter Throughout this paper 119862 (withor without index) denotes a generic positive constant whichdoes not depend on the spatial and time discretizationparameters ℎ and 119896 respectively
21 Notations We will use sdot 119898and | sdot |
119898(resp sdot
119898119901and
| sdot |119898119901
) to denote the norm and seminorm of the Sobolevspace119867119898
(Ω) (resp119882119898119901(Ω)) The scalar product and norm
in 1198712(Ω) are denoted by (sdot sdot) and sdot respectively Let1198670
1(Ω)
be the standard Sobolev subspace of 1198671(Ω) of functions
vanishing on 120597ΩThe weak form of (1) is used to find 119906(sdot 119905) [0 119879] rarr
1198671
0(Ω) such that
(119906119905 V) + 119860 (119905 119906 V) + int
119905
0
119861 (119905 119904 119906 (119904) V) 119889119904
= (119891 V) forallV isin 1198671
0(Ω)
119906 (0) = 1199060
(2)
where
119860 (119905 119906 V) = intΩ
119860 (119909 119905) nabla119906 sdot nablaV
119861 (119905 119904 119906 (119904) V) = intΩ
119861 (119909 119905 119904) nabla119906 (119904) sdot nablaV
(3)
LetTℎbe a decomposition ofΩ into triangles (for the 2D
case) or tetrahedral (for the 3D case) with ℎ = max ℎ119870 where
ℎ119870is the diameter of the element119870 isin T
ℎ
In order to describe the FVEmethod for solving problem(1) we will introduce a dual partition Tlowast
ℎbased upon the
original partition Tℎwhose elements are called control
volumes We construct the control volumes in the same wayas in [7 17] Let 119911
119870be a point of 119870 isin T
ℎ In the 2D case
on each edge 119890 of 119870 a point 119902119890is selected then we connect
119911119870with line segments to 119902
119890 thus partitioning 119870 into three
quadrilaterals 119870119911 119911 isin 119885
ℎ(119870) where 119885
ℎ(119870) are the vertices
of 119870 Then with each vertex 119911 isin 119885ℎ
= cup119870isinTℎ
119885ℎ(119870) we
associate a control volume 119881119911 which consists of the union of
the subregions119870119911 sharing the vertex 119911 (see Figure 1)
Similarly in the 3D case on each of the four faces 119878119894 119894 =
1 4 a point 119902119878119894 119894 = 1 4 is selected and on each of the
six edges 119890 a point 119902119890is selected On each of the two faces 119878
1
and 1198782of119870 sharing an edge 119890 we connect 119902
119878119894 119894 = 1 2 with 119902
119890
andwith 119911119870by line segments thus partitioning119870 into twelve
tetrahedron 119870119911 119911 isin 119885
ℎ(119870) (see Figure 2) Then for 119911 isin 119885
ℎ
the control volume119881119911consists of the union of the subregions
119870119911sharing the vertex 119911 Thus we finally obtain a group of
control volumes covering the domain Ω which is called thedual partitionTlowast
ℎof the triangulationT
ℎ We denote by 1198850
ℎ
the set of interior vertices and 119873ℎ= 1198850
ℎ For a vertex 119911
119894isin
1198850
ℎ let Π(119894) be the index set of those vertices that along with
119911119894are in some element of 119879
ℎ(Figure 2)
There are various ways to introduce a regular dualpartitionTlowast
ℎ In this paper we will also use the construction
of the control volumes in which we let 119911119870be the barycenter
of 119870 isin Tℎ In the 2D case we choose 119902
119890to be the midpoint
of the edge 119890 (see Figure 3)In the 3D case we choose 119902
119890to be the midpoint of the
edge 119890 and 119902119878119894to be the barycenter of the face 119878
119894(Figure 4)
We call the partitionTlowast
ℎregular or quasiuniform if there
exists a positive 119862 gt 0 such that
119862minus1ℎ2le meas (119881
119911) le 119862ℎ
2 forall119881
119911isin T
lowast
ℎ (4)
If the finite element triangulation Tℎis quasiuniform
that is there exists a positive 119862 gt 0 such that
119862minus1ℎ2le meas (119870) le 119862ℎ
2 forall119870 isin T
ℎ (5)
then the dual partition Tlowast
ℎis also quasiuniform
Based on the triangulation 119879ℎ let 119878
ℎbe the standard con-
forming finite element space of piecewise linear functionsdefined on the triangulation 119879
ℎas follows
119878ℎ= V isin C (Ω) V|119870 is linear forall119870 isin 119879
ℎ and V|Γ = 0
(6)
Let 119868ℎ
C(Ω) rarr 119878ℎbe the standard interpolation
operators such that
119868ℎ119906 = sum
119911isin1198850
ℎ
V119911(119905) 120593
119911(119909) forallV isin 119878
ℎ (7)
where 120593119911119911isin1198850
ℎ
are the standard basis functions of 119878ℎand
V119911(119905) = V(119905 119911)
Journal of Mathematics 3
z
Vz
(a)
z
K
Kz
zK
(b)
Figure 1 (a) A sample region with blue lines indicating the corresponding control volume 119881119911 (b) A triangle 119870 partitioned into three
subregions119870119911
Kz
qs1 qs2
qe
zK
z
Figure 2 A tetrahedron 119870 partitioned into twelve subregions119870119911
22 Construction of the FVE Scheme We formulate the FVEmethod for the problem (1) as follows Given a 119911 isin 119885
0
ℎ
integrating (1)1 over the associated control volume 119881119911and
applying Greenrsquos formula we obtain an integral conservationas follows form
int119881119911
119906119905minus int
120597119881119911
119860 (119909 119905) nabla119906 sdot 119899119889119904 minus int120597119881119911
119861 (119909 119905 119904) nabla119906 sdot 119899119889119904
= int119881119911
119891 (119909 119905)
(8)
where 119899 denotes the unit outer normal vector to 120597119881119911
Let 119868lowastℎ C(Ω) rarr 119878
lowast
ℎbe the transfer operator defined by
119868lowast
ℎV = sum
119911isin1198850
ℎ
V (119911) 120594119911 forallV isin 119878
ℎ (9)
where
119878lowast
ℎ= V isin 119871
2(Ω) V
119894
1003816100381610038161003816119881119911is constant forall119911 isin 119885
0
ℎ (10)
and 120594119911is the characteristic function of the control volume119881
119911
Now for 119905 gt 0 and for an arbitrary 119868lowastℎV we multiply (8)
by V(119911) and sum over all 119911 isin 1198850
ℎ Then the semidiscrete FVE
approximation119906ℎof (1) is a solution to the following problem
find 119906ℎ(119905) isin 119878
ℎfor 119905 gt 0 such that
(119906ℎ119905 V
ℎ) + 119860 (119905 119906
ℎ V
ℎ) + int
119905
0
119861 (119905 119904 119906ℎ(119904) V
ℎ) 119889119904
= (119891 Vℎ) V
ℎisin 119878
lowast
ℎ
119906ℎ(0) = 119906
0ℎisin 119878
ℎ
(11)
Here the bilinear forms 119860(119905 119906 V) and 119861(119905 119904 119906 V) aredefined by
119860(119905 119906 V)
=
minussum
119911isin1198850
ℎ
V119894 int120597119881119911
119860(119909 119905) nabla119906 sdot 119899119889119904 (119906 V) isin ((1198671
0cap 1198672) cup 119878ℎ) times 119878
lowast
ℎ
int
Ω
119860(119909) nabla119906 sdot nablaV119889119909 (119906 V) isin 1198671
0times 1198671
0
119861 (119905 119904 119906 V)
=
minussum
119911isin1198850
ℎ
V119911 int120597119881119911
119861 (119909 119905 119904) nabla119906 sdot 119899119889119904 (119906 V) isin ((1198671
0cap 1198672) cup 119878ℎ) times 119878
lowast
ℎ
int
Ω
119861 (119909 119905 119904) nabla119906 sdot nablaV119889119909 (119906 V) isin 1198671
0times 1198671
0
(12)
Let
119906ℎ=
119873ℎ
sum
119895=1
120572119911(119905) 120593
119911(119909)
120572 (119905) = (1205721(119905) 120572
2(119905) 120572
119873ℎ(119905))
119879
(13)
Then we can rewrite scheme (11)1 as systems of ordinarydifferential equations as follows
119872ℎ1205721015840(119905) + 119860
ℎ(119905) 120572 (119905) + int
119905
0
119861ℎ(119905 119904) 120572 (119904) 119889119904 = 119865
ℎ(119905) (14)
4 Journal of Mathematics
z
Vz
(a)
z
K
Kz
zK
(b)
Figure 3 119911119870is the barycenter of 119870 and 119902
119890is to be the midpoint of the edge 119890
Kz
zK
z
Figure 4 119902119890is the midpoint of the edge 119890 and 119902
119878119894is the barycenter
of the face 119878119894
Here 119865ℎ(119905) = (119891
1(119905) 119891
2(119905) 119891
119873ℎ(119905))
119879 the mass matrix119872
ℎ= 119872
ℎ119894119895 = (120593
119894 120594
119895) is tridiagonal and both 119860
ℎ(119905) =
119860(119905 120593119894 120594
119895) and 119861
ℎ(119905 119904) = 119861(119905 119904 120593
119894 120594
119895) are positive
definitesIn order to describe features of the bilinear forms defined
in (11) we introduce some discrete norms on 119878ℎin the same
way as in [7]1003817100381710038171003817Vℎ
1003817100381710038171003817
2
0ℎ= (V
ℎ V
ℎ)0ℎ
= (119868lowast
ℎVℎ 119868
lowast
ℎVℎ)
1003816100381610038161003816Vℎ1003816100381610038161003816
2
1ℎ= sum
119909119894isin1198850
ℎ
sum
119909119895isinΠ(119894)
meas (119881119894) (
V119894minus V
119895
119889119894119895
)
2
1003817100381710038171003817Vℎ1003817100381710038171003817
2
1ℎ=1003817100381710038171003817Vℎ
1003817100381710038171003817
2
0ℎ+1003816100381610038161003816Vℎ
1003816100381610038161003816
2
1ℎ
1003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816Vℎ1003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816
2
= (Vℎ 119868
lowast
ℎVℎ)
(15)
where 119889119894119895
= 119889(119909119894 119909
119895) the distance between 119909
119894and 119909
119895
Obviously these norms are well defined for Vℎisin 119878
lowast
ℎas well
and Vℎ0ℎ
= |||Vℎ|||
Hereafter we state the equivalence of discrete norms sdot
0ℎand sdot
1ℎwith usual norms sdot and sdot
1on 119878
ℎ
respectively
Lemma 1 (see [7]) There exist two positive constants 1198620and
1198621such that for all V
ℎisin 119878
ℎ we have
1198620
1003817100381710038171003817Vℎ10038171003817100381710038170ℎ
le1003817100381710038171003817Vℎ
1003817100381710038171003817 le 1198621
1003817100381710038171003817Vℎ10038171003817100381710038170ℎ
forallVℎisin 119878
ℎ
1198620
1003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816Vℎ1003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816 le1003817100381710038171003817Vℎ
1003817100381710038171003817 le 1198621
1003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816Vℎ1003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816 forallVℎisin 119878
ℎ
1198620
1003817100381710038171003817Vℎ10038171003817100381710038171ℎ
le1003817100381710038171003817Vℎ
10038171003817100381710038171le 119862
1
1003817100381710038171003817Vℎ10038171003817100381710038171ℎ
forallVℎisin 119878
ℎ
(16)
Next we recall some properties of the bilinear forms (see[7 18])
Lemma 2 (see [7]) There exist two positive constants 119862 and119862
0such that for all 119906
ℎ V
ℎisin 119878
ℎ we have
119860 (119906ℎ 119868
lowast
ℎVℎ) le 119862
1003817100381710038171003817119906ℎ
10038171003817100381710038171
1003817100381710038171003817Vℎ10038171003817100381710038171 forall119906
ℎ V
ℎisin 119878
ℎ
119860 (Vℎ 119868
lowast
ℎVℎ) ge 119862
0
1003817100381710038171003817Vℎ1003817100381710038171003817
2
1 forallV
ℎisin 119878
ℎ
(17)
The following lemmas are proved in [3 7] which give thekey feature of the bilinear forms in the FVE method
Lemma 3 (see [3]) Assume that 120593 isin 1198821119901
0 Then one has
119860 (119905 120593 Vℎ) minus 119860 (119905 120593 119868
lowast
ℎVℎ)
= sum
119870isin120591ℎ
int120597119870
(119860 (119905) nabla120593 sdot n) (Vℎminus 119868
lowast
ℎVℎ) 119889119904
minus sum
119870isin120591ℎ
int119870
(nabla sdot 119860 (119905) nabla120593) (Vℎminus 119868
lowast
ℎVℎ) 119889119904 forallV
ℎisin 119878
ℎ
(18)
The aforementioned identity holds true when 119860(sdot sdot) is replacedby 119861(119905 119904 sdot sdot)
Lemma 4 (see [3]) Assume that 120593 isin 119878ℎ Then one has
119860 (119905 120593 120594) minus 119860 (119905 120593 119868lowast
ℎ120594) le 119862ℎ
100381610038161003816100381612059310038161003816100381610038161119901
100381610038161003816100381612059410038161003816100381610038161119902
(19)
Furthermore for 120593 isin 1198821119901
0cap119882
2119901 we have
119860 (119905 120593 120594) minus 119860 (119905 120593 119868lowast
ℎ120594) le 119862ℎ
100381710038171003817100381712059310038171003817100381710038172119901
100381710038171003817100381712059410038171003817100381710038171119902
(20)
Journal of Mathematics 5
3 Ritz-Volterra Projection andRelated Estimates
Following [7 19 20] we define the Ritz-Volterra projection119881ℎ(119905) 119867
1
0rarr 119878
ℎas follows
119860 (119905 119906 minus 119881ℎ119906 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 119906 (119904) minus 119881ℎ119906 (119904) 119868
lowast
ℎVℎ) 119889119904 = 0
119905 gt 0 forallVℎisin 119878
ℎ
(21)
This 119881ℎ(119905) is an elliptic projection with memory of 119906
into 119878lowast
ℎ It is easy to see that (21) is actually a system of
integral equations of Volterra type In fact if 119881ℎ(119905)119906 =
sum119873ℎ
119895=1120572119895(119905)120593
119895(119909) then (21) can be rewritten as
119860ℎ(119905) 120572 (119905) + int
119905
0
119861ℎ(119905 119904) 120572 (119904) 119889119904 = 119865
ℎ(119905) (22)
where 119860ℎ(119905) 119861
ℎ(119905 119904) are matrices and 120572(119905) 119865
ℎ(119905) are vectors
defined via
120572 (119905) = (1205721(119905) 120572
2(119905) 120572
119873ℎ(119905))
119879
119865ℎ119896(119905) = 119860 (119905 119906 120594
119896) + int
119905
0
119861 (119905 119904 119906 (119904) 120594119896) 119889119904
119896 = 1 2 119873ℎ
119860ℎ(119905) = 119860 (119905 120593
119896(119909) 120594
119897) 119861
ℎ(119905 119904) = 119861 (119905 119904 120593
119896(119909) 120594
119897)
(23)
From the positivity of 119860 (Lemma 2) and the linearity of(22) we see that the system (22) possesses a unique solution120572(119905) Consequently 119881
ℎ(119905)119906 in (21) is well defined
Set 120588 = 119906 minus 119881ℎ(119905)119906 The following lemma was proved in
[7] which shows the1198671 error estimate for 120588 and its temporalderivative
Lemma 5 (see [7]) Assume that 119863119899
119905119906 isin 119871
infin(119867
1
0cap 119867
2) for all
0 le 119899 le 119896 for some integer 119896 ge 0 Then for 119879 gt 0 fixed thereis a constant 119862 = 119862(119879 119896) gt 0 independent of ℎ and 119906 suchthat for all 0 le 119899 le 119896 and 0 lt 119905 lt 119879
1003817100381710038171003817120588 (119905)10038171003817100381710038171
le 119862ℎ(1199062 + int
119905
0
1199062119889119904)
1003817100381710038171003817119863119899
119905120588 (119905)
10038171003817100381710038171le 119862ℎ(
119899
sum
119894=0
10038171003817100381710038171003817119863
119894
119905119906100381710038171003817100381710038172
+ int
119905
0
1199062119889119904)
(24)
Now we establish 1198712 error estimate for 120588 and its temporalderivative which improves Theorem 22 in [7] This estimateis optimal with respect to the order
Lemma 6 Assume that for some integer 119896 ge 0 119863119899
119905119906 isin
119871infin(119867
1
0cap 119867
2) for all 0 le 119899 le 119896 Then for 119879 gt 0 fixed there is
a constant 119862 = 119862(119879 119896) gt 0 independent of ℎ and 119906 such thatfor all 0 le 119899 le 119896 and 0 lt 119905 lt 119879
1003817100381710038171003817120588 (119905)1003817100381710038171003817 le 119862ℎ
2(1199062 + int
119905
0
1199062119889119904)
1003817100381710038171003817119863119899
119905120588 (119905)
1003817100381710038171003817 le 119862ℎ2(
119899
sum
119894=0
10038171003817100381710038171003817119863
119894
119905119906100381710038171003817100381710038172
+ int
119905
0
1199062119889119904)
(25)
Proof The proof will proceed by duality argument Let 120595 isin
1198672(Ω) cap 119867
1
0(Ω) be the solution of
119860lowast(119905) 120595 = 120588 in Ω
120595 = 0 in 120597Ω
(26)
The solution 120595 isin 1198672(Ω) cap 119867
1
0(Ω) satisfies the following
regularity estimate1003817100381710038171003817120595
10038171003817100381710038172le 119862
10038171003817100381710038171205881003817100381710038171003817 (27)
Multiplying this equation by 120588 and then taking 1198712 innerprod-uct overΩ we obtain the following
10038171003817100381710038171205881003817100381710038171003817
2
= 119860 (119905 120588 120595)
= 119860 (119905 120588 120595 minus 119877ℎ120595) + 119860 (119905 120588 119877
ℎ120595 minus 119868
lowast
ℎ(119877
ℎ120595))
minus int
119905
0
119861 (119905 119904 120588 (119904) 119868lowast
ℎ119877ℎ120595 minus 119877
ℎ120595) 119889119904
minus int
119905
0
119861 (119905 119904 120588 (119904) 119877ℎ120595 minus 120595) 119889119904
minus int
119905
0
119861 (119905 119904 120588 (119904) 120595) 119889119904 = 1198681+ 119868
2+ 119868
3+ 119868
4+ 119868
5
(28)
We have
100381610038161003816100381611986811003816100381610038161003816 +
100381610038161003816100381611986841003816100381610038161003816 le 119862ℎ
2(1199062 + int
119905
0
1199062119889119904)1003817100381710038171003817120595
10038171003817100381710038172 (29)
Applying Lemma 4 we obtain
100381610038161003816100381611986821003816100381610038161003816 +
100381610038161003816100381611986831003816100381610038161003816 le 119862ℎ
2(1199062 + int
119905
0
1199062119889119904)1003817100381710038171003817120595
10038171003817100381710038172 (30)
Finally we have
100381610038161003816100381611986851003816100381610038161003816 le int
119905
0
(120588 (119904) 119861lowast(119905 119904) 120595) 119889119904 le 119862(int
119905
0
10038171003817100381710038171205881003817100381710038171003817 119889119904)
100381710038171003817100381712059510038171003817100381710038172 (31)
then we have
10038171003817100381710038171205881003817100381710038171003817 le 119862ℎ
2(1199062 + int
119905
0
1199062119889119904) + 119862(int
119905
0
10038171003817100381710038171205881003817100381710038171003817 119889119904) (32)
Finally an application of Gronwallrsquos lemma yields the firstestimate
The second inequality follows in a similar fashion
6 Journal of Mathematics
Lemma7 There exists a constant119862 independent of ℎ such that
100381710038171003817100381712058810038171003817100381710038170119901
+ ℎ100381710038171003817100381712058810038171003817100381710038171119901
le 119862ℎ2(1199062119901 + int
119905
0
1199062119901119889119904) (33)
Proof Let 120588119909be an arbitrary component of nabla120588 with 119901 and
119902 conjugate indices we have 120588119909119901
= sup(120588119909 120593) 120593 isin
Cinfin
0(Ω) 120593
119902= 1
For any such 120593 let 120595 be the solution of
119860lowast(119905 120595 V) = minus (120593
119909 V) forallV isin 119867
1
0(Ω)
120595 = 0 on 120597Ω
(34)
It follows from the regularity theory for the elliptic problemthat
100381710038171003817100381712059510038171003817100381710038171119902
le 119862119901
10038171003817100381710038171205931003817100381710038171003817119902
= 119862119901 (35)
We then have by application of (21) that
(120588119909 120593) = 119860 (119905 120588 120595) = 119860 (119905 120588 120595 minus 119877
ℎ120595)
+ 119860 (119905 120588 119877ℎ120595 minus 119868
lowast
ℎ(119877
ℎ120595))
+ int
119905
0
119861 (119905 119904 120588 (119904) 119868lowast
ℎ(119877
ℎ120595)) 119889119904
= 1198681+ 119868
2+ 119868
3
119860 (119905 120588 120595 minus 119877ℎ120595) = 119860 (119905 119877
ℎ119906 minus 119906 120595)
= minus ((119877ℎ119906 minus 119906)
119909 120593) le 119862ℎ1199062119901
(36)
Applying Lemma 4 we have
1198682= 119860 (119905 119906 119877
ℎ120595 minus 119868
lowast
ℎ(119877
ℎ120595)) minus 119860 (119905 119881
ℎ119906 119877
ℎ120595 minus 119868
lowast
ℎ(119877
ℎ120595))
le 119862ℎ1199062119901
(37)
Finally 1198683is estimated as follows
1198683= int
119905
0
119861 (119905 119904 120588 (119904) 119868lowast
ℎ(119877
ℎ120595)) 119889119904 le 119862
119901int
119905
0
100381710038171003817100381712058810038171003817100381710038171119901
119889119904 (38)
Combining these estimates we get
100381710038171003817100381712058810038171003817100381710038171119901
le 119862ℎ1199062119901 + 119862119901int
119905
0
100381710038171003817100381712058810038171003817100381710038171119901
119889119904 (39)
hence by Gronwallrsquos lemma
100381710038171003817100381712058810038171003817100381710038171119901
le 119862ℎ(1199062119901 + int
119905
0
1199062119901119889119904) (40)
The derivation of the error estimate in 119871119901 is similar to the casewhen 119901 = 2
4 Error Estimates forSemidiscrete Approximations
We split the error 119890(119905) = 119906(119905) minus 119906ℎ(119905) as follows
119890 (119905) = (119906 (119905) minus 119881ℎ119906 (119905)) + (119881
ℎ119906 (119905) minus 119906
ℎ(119905)) = 120588 + 120579 (41)
It is easy to see that 120579 = 119881ℎ119906(119905) minus 119906
ℎ(119905) isin 119878
ℎsatisfies an
error equation of the form
(120579119905 119868
lowast
ℎVℎ) + 119860 (119905 120579 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎVℎ) 119889119904
= minus (120588119905 119868
lowast
ℎVℎ) V
ℎisin 119878
ℎ
(42)
Since the estimates of 120588 are already known it is enoughto have estimates for 120579
We will prove a sequence of lemmas which lead to thefollowing result
Lemma8 There is a positive constant119862 independent of ℎ suchthat
|||120579 (119905)||| le 119862(|||120579 (0)|||2+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817 119889119904) (43)
Proof Since 120579 isin 119878ℎwe may take V
ℎ= 120579 in (42) to obtain
1
2
119889
119889119905|||120579 (119905)|||
2+ 119888120579
2
1le
10038171003817100381710038171205881199051003817100381710038171003817 120579 + 119862int
119905
0
12057911198891199041205791
le1003817100381710038171003817120588119905
1003817100381710038171003817 120579 +1
2119888120579
2
1+ 119862int
119905
0
1205792
1119889119904
(44)
and hence by integration and Lemma 1 we have
||120579 (119905)||2+ int
119905
0
1205792
1119889119904
le 119862(|||120579 (0)|||2+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817 120579 119889119904 + int
119905
0
int
119904
0
120579 (120591)2
1119889120591119889119904)
(45)
Gronwallrsquos lemma now implies the following
|||120579 (119905)|||2+ int
119905
0
1205792
1119889119904 le 119862(|||120579 (0)|||
2+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817 120579 119889119904)
le 119862|||120579 (0)|||2+1
2sup119904le119905
120579 (119904)2
+ (int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817 119889119904)
2
(46)
Since this holds for all isin 119869 we may conclude that
||120579 (119905)|| le 119862(|||120579 (0)||| + int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817 119889119904) (47)
Journal of Mathematics 7
Remark 9 If the initial value was chosen so that 1199060ℎminus 119906
0 le
119862ℎ2119906
02 then 120579(0) le 119906
0ℎminus119906
0+119881
ℎ1199060minus119906
0 le 119862ℎ
2119906
02
One can derive
|||120579 (119905)||| le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (48)
Lemma 10 There is a positive constant 119862 independent of ℎsuch that
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
119889119904 + 1205792
1le 119862(120579 (0)
2
1+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
2
119889119904) (49)
Proof Set Vℎ= 120579
119905in (42) to get
10038171003817100381710038171205791199051003817100381710038171003817
2
+1
2
119889
119889119905119860 (119905 120579 119868
lowast
ℎ120579)
= minus (120588119905 119868
lowast
ℎ120579119905) minus int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579119905(119905)) 119889119904
+1
2119860
119905(119905 120579 119868
lowast
ℎ120579)
+1
2[119860 (119905 120579
119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)]
le1
2
10038171003817100381710038171205881199051003817100381710038171003817
2
+1
2
1003816100381610038161003816
1003816100381610038161003816
10038161003816100381610038161205791199051003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816
2
+ 119860119905(119905 120579 119868
lowast
ℎ120579)
+1
2[119860 (119905 120579
119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)]
minus119889
119889119905int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579 (119905)) 119889119904
+ 119861 (119905 119905 120579 (119905) 119868lowast
ℎ120579 (119905)) + int
119905
0
119861119905(119905 119904 120579 (119904) 119868
lowast
ℎ120579 (119905)) 119889119904
(50)
Then
10038171003817100381710038171205791199051003817100381710038171003817
2
+119889
119889119905119860 (119905 120579 119868
lowast
ℎ120579)
le1003817100381710038171003817120588119905
1003817100381710038171003817
2
minus119889
119889119905int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579) 119889119904
+ 119862(1205792
1+ int
119905
0
120579 (119904)2
1119889119904)
+1
2[119860 (119905 120579
119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)]
(51)
In addition recall that
119860 (119905 119906ℎ 119868
lowast
ℎVℎ) minus 119860 (119905 V
ℎ 119868
lowast
ℎ119906ℎ) le 119862ℎ
1003817100381710038171003817119906ℎ
10038171003817100381710038171
1003817100381710038171003817Vℎ10038171003817100381710038171
forall119906ℎ V
ℎisin 119878
ℎ
(52)
then applying an inverse inequality and using kickbackargument we obtain
[119860 (119905 120579119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)] le 119862ℎ
100381710038171003817100381712057911990510038171003817100381710038171
1205791 le 1198621003817100381710038171003817120579119905
1003817100381710038171003817 1205791
le 1205761003817100381710038171003817120579119905
1003817100381710038171003817
2
+ 1198621205792
1
(53)
Combining these estimates we derive
10038171003817100381710038171205791199051003817100381710038171003817
2
+119889
119889119905119860 (119905 120579 119868
lowast
ℎ120579)
le1003817100381710038171003817120588119905
1003817100381710038171003817
2
minus119889
119889119905int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579) 119889119904
+ 119862(1205792
1+ int
119905
0
120579 (119904)2
1119889119904)
(54)
So after integration in time and using the weak coercivity of119860(119905 120579 119868
lowast
ℎ120579) we get
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
119889119904 + 1198880120579
2
1
le 1198880120579 (0)
2
1+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
2
119889119904
+ int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579) 119889119904 + 119862int
119905
0
120579 (119904)2
1119889119904
le 1198880120579 (0)
2
1+119888
2120579
2
1+ 119862(int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
2
+ 120579 (119904)2
1119889119904)
(55)
and by Gronwallrsquos lemma
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
119889119904 + 1198881205792
1le 119862(120579 (0)
2
1+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
2
119889119904) (56)
Remark 11 If 120579(0) = 0 then
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
119889119904 + 1198881205792
1le 119862ℎ
2(int
119905
0
1003817100381710038171003817119906119905
1003817100381710038171003817
2
2119889119904) (57)
Theorem 12 (error estimates in 1198712 and1198671-norms) Let 119906 119906
ℎ
be the solutions of (2) and (11) respectively Assume that 119906 119906119905isin
119871infin(119867
1
0cap 119867
2)
(a) Let 1199060ℎ
be chosen so that 1199060ℎ
minus 1199060 le 119862ℎ
2119906
02
Then for 119879 gt 0 fixed there is a constant 119862 = 119862(119879)
independent of ℎ such that for all 0 lt 119905 lt 119879
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905)
1003817100381710038171003817 le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (58)
(b) Let 1199060ℎ
be chosen so that 1199060ℎminus 119906
01
le 119862ℎ11990602
Then for 119879 gt 0 fixed there is a constant 119862 = 119862(119879)
independent of ℎ such that for all 0 lt 119905 lt 119879
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905))
10038171003817100381710038171le 119862ℎ(
10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (59)
We now prove error estimates for FVE approximations in119871119901 and119882
1119901-norms
8 Journal of Mathematics
Theorem 13 (error estimates in 119871119901 and 119882
1119901-norms) Let119906 119906
ℎbe the solutions of (2) and (11) respectively and 119906
0ℎ=
119881ℎ1199060 Assume that 119906 119906
119905isin 119871
infin(119867
1
0cap 119882
2119901) For ℎ sufficiently
small we have
1003817100381710038171003817119906 minus 119906ℎ
10038171003817100381710038170119901le 119862ℎ
2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
1003817100381710038171003817119906 minus 119906ℎ
10038171003817100381710038171119901le 119862ℎ(
10038171003817100381710038171199060
10038171003817100381710038172+ 1199062119901 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
(60)
Proof If 2 le 119901 lt infin by the following Sobolev embeddinginequality
1205790119901 le 1198621205791 (61)
then the first desired estimate follows from Lemmas 7 and 10Given 120593 isin Cinfin
0(Ω) find 120595 isin 119867
1
0(Ω) such that
119860(119905)lowast120595 = minus120593
119909 in Ω
120595 = 0 on 120597Ω
100381710038171003817100381712059510038171003817100381710038171119902
le100381710038171003817100381712059310038171003817100381710038170119902
(62)
We have
((119906 minus 119906ℎ)119909 120593) = 119860 (119905 119906 minus 119906
ℎ 120595) = 119860 (119905 119906 minus 119906
ℎ 120595 minus 119877
ℎ120595)
+ 119860 (119905 119906 minus 119906ℎ 119877
ℎ120595 minus 119868
lowast
ℎ119877ℎ120595)
minus int
119905
0
119861 (119905 119904 (119906 minus 119906ℎ) (119904) 119868
lowast
ℎ119877ℎ120595) 119889119904
minus ((119906 minus 119906ℎ)119905 119868
lowast
ℎ119877ℎ120595)
= 1198681+ 119868
2+ 119868
3+ 119868
4
100381610038161003816100381611986811003816100381610038161003816 le
1003816100381610038161003816119860 (119905 119906 minus 119877ℎ119906 120595)
1003816100381610038161003816 le 1198621003817100381710038171003817119906 minus 119877
ℎ11990610038171003817100381710038171119901
100381710038171003817100381712059510038171003817100381710038171119902
le 119862ℎ11990621199011003817100381710038171003817120595
10038171003817100381710038171119902
(63)
By Lemma 4
100381610038161003816100381611986821003816100381610038161003816 le 119860 (119905 119906 minus 119906
ℎ 119877
ℎ120595 minus 119868
lowast
ℎ119877ℎ120595)
le 119862ℎ (1003816100381610038161003816119906 minus 119906
ℎ
10038161003816100381610038161119901+ |119906|2119901)
100381710038171003817100381712059510038171003817100381710038171119902
100381610038161003816100381611986831003816100381610038161003816 le int
119905
0
1003817100381710038171003817119906 minus 119906ℎ
100381710038171003817100381711199011198891199041003817100381710038171003817120595
10038171003817100381710038171119902
100381610038161003816100381611986841003816100381610038161003816 le (
1003817100381710038171003817119906 minus 119906ℎ
1003817100381710038171003817)1003817100381710038171003817120595
1003817100381710038171003817 le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
100381710038171003817100381712059510038171003817100381710038171119902
(64)
where we have used the fact 120595 le 1205951119903 119903 gt 1 Combining
these estimates we get
1003816100381610038161003816((119906 minus 119906ℎ)119909 120593)
1003816100381610038161003816 le 119862ℎ(10038171003817100381710038171199060
10038171003817100381710038172+ 1199062119901 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
100381710038171003817100381712059510038171003817100381710038171119902
1003817100381710038171003817(119906 minus 119906ℎ)119909
10038171003817100381710038170119901= sup
((119906 minus 119906ℎ)119909 120593)
100381710038171003817100381712059310038171003817100381710038170119902
le 119862ℎ1003816100381610038161003816119906 minus 119906
ℎ
10038161003816100381610038161119901
+ 119862ℎ(10038171003817100381710038171199060
10038171003817100381710038172+ 1199062119901 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
(65)
Hence using the Poincare inequality we have for ℎ sufficientlysmall
1003817100381710038171003817119906 minus 119906ℎ
10038171003817100381710038171119901le 119862ℎ(
10038171003817100381710038171199060
10038171003817100381710038172+ 1199062119901 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (66)
We compare the relationship between covolume solutionand the Galerkin finite element solution
Corollary 14 Let ℎbe the finite element solution to (2) that
is
(ℎ119905 V
ℎ) + 119860 (119905
ℎ V
ℎ)
+ int
119905
0
119861 (119905 119904 ℎ(119904) V
ℎ) 119889119904 = (119891 V
ℎ) V
ℎisin 119878
ℎ
ℎ(0) = 119877
ℎ1199060
(67)
For ℎ sufficiently small we have
1003817100381710038171003817(ℎminus 119906
ℎ)10038171003817100381710038171119901
le 119862(
ℎ1003817100381710038171003817119906 minus 119906
ℎ
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus 119906
ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817
+int
119905
0
(1003817100381710038171003817(119906 minus 119906
ℎ) (119904)
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus
ℎ) (119904)
10038171003817100381710038171119901) 119889119904
)
le 119862 (119906) ℎ
(68)
Proof By (2) and (67)
((ℎminus 119906)
119905 V
ℎ) + 119860 (119905
ℎminus 119906 V
ℎ)
+ int
119905
0
119861 (119905 119904 (ℎminus 119906) (119904) V
ℎ) 119889119904 = 0 V
ℎisin 119878
ℎ
(69)
Consider the following auxiliary problem For any such 120593 let120595 be the solution of the following
119860(119905)lowast120595 = minus120593
119909 in Ω
120595 = 0 on 120597Ω
(70)
Journal of Mathematics 9
with1003817100381710038171003817120595
10038171003817100381710038171119902le100381710038171003817100381712059310038171003817100381710038170119902
((ℎminus 119906
ℎ)119909 120593)
= 119860 (119905 ℎminus 119906
ℎ 120595)
= 119860 (119905 ℎminus 119906
ℎ 120595 minus 119877
ℎ120595) + 119860 (119905 119906 minus 119906
ℎ 119877
ℎ120595)
minus 119860 (119905 119906 minus 119906ℎ 119868
lowast
ℎ119877ℎ120595) minus ((119906 minus 119906
ℎ)119905 119868
lowast
ℎ119877ℎ120595)
minus int
119905
0
119861 (119905 119904 (119906 minus 119906ℎ) (119904) 119868
lowast
ℎ119877ℎ120595) 119889119904
+ 119860 (119905 ℎminus 119906 119877
ℎ120595)
= [119860 (119905 119906 minus 119906ℎ 119877
ℎ120595) minus 119860 (119905 119906 minus 119906
ℎ 119868
lowast
ℎ119877ℎ120595)]
minus ((119906 minus 119906ℎ)119905 119868
lowast
ℎ119877ℎ120595) minus ((
ℎminus 119906)
119905 119877
ℎ120595)
minus int
119905
0
119861 (119905 119904 (119906 minus 119906ℎ) (119904) 119868
lowast
ℎ119877ℎ120595) 119889119904
minus int
119905
0
119861 (119905 119904 (ℎminus 119906) (119904) 119877
ℎ120595) 119889119904
= 1198681+ 119868
2+ 119868
3
(71)
On the other hand10038161003816100381610038161198681
1003816100381610038161003816 le 119862ℎ1003817100381710038171003817119906 minus 119906
ℎ
10038171003817100381710038171119901
100381710038171003817100381712059510038171003817100381710038171119902
100381610038161003816100381611986821003816100381610038161003816 le 119862 (
1003817100381710038171003817(119906 minus 119906ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817)1003817100381710038171003817120595
1003817100381710038171003817
le 119862 (1003817100381710038171003817(119906 minus 119906
ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817)1003817100381710038171003817120595
10038171003817100381710038171119902
(72)
where we have used the fact 120595 le 1205951119903 119903 gt 1
100381610038161003816100381611986831003816100381610038161003816 le int
119905
0
(1003817100381710038171003817(119906 minus 119906
ℎ) (119904)
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus
ℎ) (119904)
10038171003817100381710038171119901) 119889119904
100381710038171003817100381712059510038171003817100381710038171119902
1003817100381710038171003817(ℎminus 119906
ℎ)119909
10038171003817100381710038170119901
= sup120593isinCinfin0
((ℎminus 119906
ℎ)119909 120593)
100381710038171003817100381712059310038171003817100381710038170119902
le 119862(
ℎ1003817100381710038171003817119906 minus 119906
ℎ
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus 119906
ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817
+int
119905
0
(1003817100381710038171003817(119906 minus 119906
ℎ) (119904)
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus
ℎ) (119904)
10038171003817100381710038171119901) 119889119904
)
(73)
We deduce the result from the known finite element esti-mates
Remark 15 In order to estimate (119906 minus 119906ℎ)119905 by differentiating
(42) with respect to 119905 we obtain
(120579119905119905 119868
lowast
ℎVℎ) + 119860 (119905 120579
119905 119868
lowast
ℎVℎ) + 119860
119905(119905 120579
119905 119868
lowast
ℎVℎ)
+ 119861 (119905 119905 120579 119868lowast
ℎVℎ) + int
119905
0
119861119905(119905 119904 120579 (119904) 119868
lowast
ℎVℎ) 119889119904
= minus (120588119905119905 119868
lowast
ℎVℎ)
(74)
Setting Vℎ= 120579
119905 we obtain
1
2
119889
119889119905
1003816100381610038161003816
1003816100381610038161003816
10038161003816100381610038161205791199051003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816
2
+ 1198881003817100381710038171003817120579119905
1003817100381710038171003817
2
1le1003817100381710038171003817120588119905119905
1003817100381710038171003817
10038171003817100381710038171205791199051003817100381710038171003817
+1
21198881003817100381710038171003817120579119905
1003817100381710038171003817
2
1+ 119862120579
2
1+ int
119905
0
1205792
1119889119904
le1003817100381710038171003817120588119905119905
1003817100381710038171003817
10038171003817100381710038171205791199051003817100381710038171003817 +
1
21198881003817100381710038171003817120579119905
1003817100381710038171003817
2
1+ 119862int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
1119889119904
(75)
Using kickback argument integrating and applying Gron-wallrsquos lemma we deduce
10038171003817100381710038171205791199051003817100381710038171003817 le 119862(
1003817100381710038171003817120579119905 (0)1003817100381710038171003817 + int
119905
0
100381710038171003817100381712058811990511990510038171003817100381710038171119889119904)
le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+10038171003817100381710038171199061
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904)
(76)
5 The Lumped Mass Finite VolumeElement Method
In this section we restrict our study to the 2D case A simpleway to define the lumped mass scheme [21] is to replace themass matrix 119872
ℎin (14) by the diagonal matrix 119872
ℎobtained
by taking for its diagonal elements the numbers 119872ℎ119894119894
=
sum119873ℎ
119895=1119872
ℎ119894119895or by lumping all masses in one row into the
diagonal entryThismakes the inversion of thematrix in frontof1205721015840
(119905) a trivialityWewill therefore study thematrix problem
119872ℎ1205721015840(119905) + 119860
ℎ(119905) 120572 (119905) + int
119905
0
119861ℎ(119905 119904) 120572 (119904) 119889119904 = 119865
ℎ(119905) (77)
We know that the lumped mass method defined by (77)above is equivalent to
(119868lowast
ℎ119906ℎ119905 119868
lowast
ℎVℎ) + 119860 (119905 119906
ℎ 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 119906ℎ(119904) 119868
lowast
ℎVℎ) 119889119904
= (119891 119868lowast
ℎVℎ) V
ℎisin 119878
ℎ
(78)
Our alternative interpretation of this procedure will beto think of (77) as being obtained by evaluating the firstterm in (78) by numerical quadrature Let 119870 be a triangle ofthe triangulation 119879
ℎ let 119909
119895 119895 = 1 2 3 be its vertices and
consider the quadrature formula
119876119870ℎ
(119891) =1
3area119870
3
sum
119895=1
119891 (119909119895) ≃ int
119870
119891119889119909 (79)
We may then define the associated bilinear form in 119878ℎtimes
119878lowast
ℎ using the quadrature scheme by the following
(Vℎ 120578
ℎ)ℎ= sum
119870isin119879ℎ
119876119870ℎ
(Vℎ120578ℎ) = sum
119909119894isin119873119886
ℎ
Vℎ(119909
119894) 120578
ℎ(119909
119894)10038161003816100381610038161003816119881119909119894
10038161003816100381610038161003816
forallVℎisin 119878
ℎ 120578
ℎisin 119878
lowast
ℎ
(80)
10 Journal of Mathematics
We note that Vℎ2
ℎ= (V
ℎ 119868
lowast
ℎVℎ)ℎis a norm in 119878
ℎwhich is
equivalent to the 1198712-norm uniformly in ℎ that is there existtwo positive constants 119862
1and 119862
2such that for all V
ℎisin 119878
ℎ we
have
1198620
1003817100381710038171003817Vℎ1003817100381710038171003817 le
1003817100381710038171003817Vℎ1003817100381710038171003817ℎ
le 1198621
1003817100381710038171003817Vℎ1003817100381710038171003817 forallV
ℎisin 119878
ℎ (81)
We note that the aforementioned definition (Vℎ 120578
ℎ)ℎmay
be used also for 120578ℎisin 119878
ℎand that (V
ℎ 119908
ℎ)ℎ= (V
ℎ 119868
lowast
ℎ119908
ℎ)ℎfor
Vℎ 119908
ℎisin 119878
ℎ
The lumpedmass method defined by (78) is equivalent to
(119906ℎ119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 119906
ℎ 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 119906ℎ(119904) 119868
lowast
ℎVℎ) 119889119904
= (119891 119868lowast
ℎVℎ) V
ℎisin 119878
ℎ
(82)
We introduce the quadrature error
120576ℎ(V
ℎ 119908
ℎ) = (V
ℎ 119908
ℎ)ℎminus (V
ℎ 119908
ℎ) (83)
Lemma 16 (see [21]) Let Vℎ 119908
ℎisin 119878
ℎ Then
1003816100381610038161003816120576ℎ (Vℎ 119908ℎ)1003816100381610038161003816 le 119862ℎ
2 1003817100381710038171003817nablaVℎ1003817100381710038171003817
1003817100381710038171003817nabla119908ℎ
1003817100381710038171003817 (84)
Theorem 17 Let 119906ℎand 119906 be the solutions of (82) and (2)
respectively and assume 119906ℎ(0) = 119877
ℎ1199060 Then we have for the
error in the lumped mass semidiscrete method for 119905 ge 0 thefollowing
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905)
1003817100381710038171003817 le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ 1199062 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (85)
Proof In order to estimate 120579 we write
(120579119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 120579 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎVℎ) 119889119904
= (119906ℎ119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 119906
ℎ 119868
lowast
ℎVℎ)
+ int
119905
0
119861 (119905 119904 119906ℎ(119904) 119868
lowast
ℎVℎ) 119889119904
minus ((119881ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus 119860 (119905 119881
ℎ119906 119868
lowast
ℎVℎ)
minus int
119905
0
119861 (119905 119904 119881ℎ119906 (119904) 119868
lowast
ℎVℎ) 119889119904
= (119891 119868lowast
ℎVℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus 119860 (119905 119906 119868
lowast
ℎVℎ)
minus int
119905
0
119861 (119905 119904 119906 (119904) 119868lowast
ℎVℎ)
= (119906119905 119868
lowast
ℎVℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)ℎ
= minus (120588119905 119868
lowast
ℎVℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)ℎ+ ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
(86)
We rewrite
((119881ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
= ((119881ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus ((119881
ℎ119906)
119905 V
ℎ)
+ ((119881ℎ119906)
119905 V
ℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
= 120576ℎ((119881
ℎ119906)
119905 V
ℎ) + ((119881
ℎ119906)
119905 V
ℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
(120579119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 120579 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎVℎ) 119889119904
= minus (120588119905 119868
lowast
ℎVℎ) + 120576
ℎ((119881
ℎ119906)
119905 V
ℎ)
+ ((119881ℎ119906)
119905 V
ℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
(87)
Setting Vℎ= 120579 in (87) we obtain
1
2
119889
119889119905120579
2
ℎ+ 119888
01205792
1
le1003817100381710038171003817120588119905
1003817100381710038171003817 120579 +1
21198880120579
2
1+ 119862int
119905
0
1205792
1119889119904
+ 120576ℎ((119881
ℎ119906)
119905 120579) + ((119881
ℎ119906)
119905 120579) minus ((119881
ℎ119906)
119905 119868
lowast
ℎ120579)
(88)
Using Lemma 16 and the inverse estimate we get1003816100381610038161003816120576ℎ (119881ℎ
119906119905 120579)
1003816100381610038161003816 le 119862ℎ2 1003817100381710038171003817nabla(119881ℎ
119906)119905
1003817100381710038171003817 nabla120579
le 119862ℎ2 1003817100381710038171003817nabla119906119905
1003817100381710038171003817 nabla120579
le 119862ℎ1003817100381710038171003817nabla119906119905
1003817100381710038171003817 120579
(89)
we have1003816100381610038161003816((119881ℎ
119906)119905 120579) minus ((119881
ℎ119906)
119905 119868
lowast
ℎ120579)1003816100381610038161003816 le 119862ℎ
1003817100381710038171003817nabla119906119905
1003817100381710038171003817 120579 (90)
Using Youngrsquos inequality and Gronwallrsquos lemma to eliminate120579
1on the right-hand side and using integration in 119905 we get
the result
1
2
119889
119889119905120579
2
ℎ+ 119888
0 120579 le1003817100381710038171003817120588119905
1003817100381710038171003817 120579 + 119862ℎ1003817100381710038171003817nabla119906119905
1003817100381710038171003817 120579 (91)
Using Youngrsquos inequality to eliminate 120579 on the right handside it becomes
Using integration in 119905 we get the result
We will now show that the 1198671-norm error bound of
theorem remains valid for the lumped mass method (82)
Theorem 18 Let 119906ℎand 119906 be the solutions of (82) and (2)
respectively and assume
119906ℎ(0) = 119877
ℎ1199060
10038171003817100381710038171199061ℎ(0) minus 119906
1
1003817100381710038171003817 le 119862ℎ210038171003817100381710038171199061
10038171003817100381710038172 (92)
Then we have for the error in the lumped mass semidiscretemethod for 119905 ge 0 the following
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905)
10038171003817100381710038171le 119862ℎ
2(10038171003817100381710038171199060
10038171003817100381710038172+10038171003817100381710038171199061
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904)
(93)
Journal of Mathematics 11
Proof Setting Vℎ= 120579
119905in (87) we obtain
10038171003817100381710038171205791199051003817100381710038171003817
2
ℎ+1
2
119889
119889119905119860 (119905 120579 119868
lowast
ℎ120579)
=1
2119860
119905(119905 120579 119868
lowast
ℎ120579) +
1
2[119860 (119905 120579
119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)]
119861 (119905 119905 120579 (119905) 119868lowast
ℎ120579 (119905)) + int
119905
0
119861119905(119905 119904 120579 (119904) 119868
lowast
ℎ120579 (119905)) 119889119904
minus119889
119889119905int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579 (119905)) 119889119904 minus (120588
119905 119868
lowast
ℎ120579119905)
minus 120576ℎ((119881
ℎ119906)
119905 120579
119905) + ((119881
ℎ119906)
119905 120579) minus ((119881
ℎ119906)
119905 119868
lowast
ℎ120579)
(94)
It follows thus that using integration in 119905 and Gronwallrsquoslemma we have
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
ℎ+ 120579
2
1le 119862nabla120579 (0)
2+ 119862int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
10038171003817100381710038171205791199051003817100381710038171003817 119889119904
+ 119862ℎ2int
119905
0
1003817100381710038171003817119906119905
1003817100381710038171003817
2
1119889119904
(95)
6 Full Discretization
Let 120597119880119899= (119880
119899minus119880
119899minus1)119896 be the backward difference quotient
of 119880119899 assume that 119860ℎ
= 119875ℎ119860 is a discrete analogue of 119860
(similarly 119861ℎ
= 119875ℎ119861) where 119875
ℎ 119871
2(Ω) rarr 119878
lowast
ℎthe 119871
2
projection is defined by
(119875ℎV 119868lowast
ℎVℎ) = (V 119868lowast
ℎVℎ) V isin 119871
2(Ω) V
ℎisin 119878
ℎ (96)
In order to define fully discrete approximation of (11) wediscretize the time by taking 119905
119899= 119899119896 119896 gt 0 119899 = 1 2 and
use the numerical quadrature
int
119905119899minus12
0
119892 (119904) 119889119904 asymp
119899
sum
119896=1
120596119899119896119892 (119905
119896minus12) 119905
119899minus12= (119899 minus
1
2) 119896
(97)
Here 120596119899119896 are the integrationweights andwe assume that
the following error estimate is valid
119902119899(119892) = int
119905119899minus12
0
119892 (119904) 119889119904minus
119899
sum
119896=1
120596119899119896119892 (119905
119896minus12)
le 1198621198962int
119905119899
0
(10038161003816100381610038161003816119892101584010038161003816100381610038161003816+100381610038161003816100381610038161198921015840101584010038161003816100381610038161003816) 119889119904
(98)
Now define our complete discrete FVE approximation of(11) by the following find 119880
119899isin 119878
ℎfor 119899 = 1 2 such that
for all Vℎisin 119878
ℎ
(120597119880119899 119868
lowast
ℎVℎ) + 119860 (119905
119899minus12 119880
119899minus12 119868
lowast
ℎVℎ)
+
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12 119880
119896minus12 119868
lowast
ℎVℎ)
= (119891119899minus12
119868lowast
ℎVℎ)
1198800 in 119878
ℎ
(99)
where 119880119899minus12= (119880
119899+ 119880
119899minus1)2
Theorem 19 Let 119906(119905) and 119880119899 be the solutions of problem (2)
and its complete discrete scheme (99) respectively Then forany 119879 gt 0 there exists a positive constant 119862 = 119862(119879) gt 0independent of ℎ such that for 0 lt 119905
119899le 119879
1003817100381710038171003817119906 (119905119899) minus 1198801198991003817100381710038171003817
le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905119899
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
+ 1198621198962(int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905119905
1003817100381710038171003817) 119889119904)
(100)
Proof Let us split the error into two parts 119906(119905119899) minus 119880
119899= 120588
119899+
120579119899 where 120588
119899= 119906(119905
119899)minus119881
ℎ119906(119905
119899) and 120579119899 = 119881
ℎ119906(119905
119899)minus119880
119899 and let119882 = 119881
ℎ119906(119905) isin 119878
ℎbe the Ritz-Volterra projection of 119906 Then
from (2) and (99) we have for all Vℎisin 119878
ℎthe following
(120597120579119899 119868
lowast
ℎVℎ) + 119860 (119905
119899minus12 120579
119899minus12 119868
lowast
ℎVℎ)
+
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12 120579
119896minus12 119868
lowast
ℎVℎ)
= minus (119903119899 119868
lowast
ℎVℎ) forallV
ℎisin 119878
ℎ
(101)
where
119903119899= 119903
1
119899+ 119903
2
119899+ 119903
3
119899+ 119903
4
119899
1199031
119899= 120597120588
119899
1199032
119899= 120597119906 (119905
119899) minus 119906
119905(119905
119899minus12)
1199033
119899= 119860(119905
119899minus12(119906 (119905
119899) + 119906 (119905
119899minus1))
2minus 119906 (119905
119899minus12))
1199034
119899= 119902
119899(119861
ℎ119882)
=
119899
sum
119896=1
120596119899119896119861ℎ(119905
119899minus12 119905
119896minus12119882
119896minus12 119868
lowast
ℎVℎ)
minus int
119905119899minus12
0
119861 (119905119899 119904119882 (119904) 119868
lowast
ℎVℎ) 119889119904
(102)
In fact by Taylor expansion
119906119899+1
= 119906119899+ 119896119906
1015840(119905
119899) + int
119905119899+1
119905119899
11990610158401015840(119904) (119905
119899+1minus 119904) 119889119904
= 119906119899+ 119896119906
1015840(119905
119899) +
1198962
211990610158401015840(119905
119899) +
1198963
6119906(3)
(119905119899)
+1
6int
119905119899+1
119905119899
119906(4)
(119904) (119905119899+1
minus 119904)3
119889119904
(103)
12 Journal of Mathematics
we have100381710038171003817100381710038171199031
119899
10038171003817100381710038171003817=
10038171003817100381710038171003817120597120588
11989910038171003817100381710038171003817le
1
119896int
119905119899
119905119899minus1
10038171003817100381710038171205881199051003817100381710038171003817 119889119904 le 119862
ℎ2
119896int
119905119899
119905119899minus1
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
100381710038171003817100381710038171199032
119899
10038171003817100381710038171003817=
10038171003817100381710038171003817120597119906 (119905
119899) minus 119906
119905(119905
119899minus12)10038171003817100381710038171003817
=1
119896
100381710038171003817100381710038171003817100381710038171003817
int
119905119899
119905119899minus1
(119906119905(119904) minus 119906
119905(119905
119899minus12)) 119889119904
100381710038171003817100381710038171003817100381710038171003817
le 119862119896int
119905119899
119905119899minus1
10038171003817100381710038171003817119906(3)
(119904)10038171003817100381710038171003817119889119904
100381710038171003817100381710038171199033
119899
10038171003817100381710038171003817=
100381710038171003817100381710038171003817100381710038171003817
119860(119905119899minus12
119906 (119905
119899) + 119906 (119905
119899minus1)
2minus 119906 (119905
119899minus12) 119868
lowast
ℎVℎ)
100381710038171003817100381710038171003817100381710038171003817
le 119862119896int
119905119899
119905119899minus1
1003817100381710038171003817119860119906119905119905(119904)
1003817100381710038171003817 119889119904 le 119862119896int
119905119899
119905119899minus1
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
(104)
In addition the quadrature error satisfies100381710038171003817100381710038171199034
119899
10038171003817100381710038171003817= 119902
119899minus12(119861
ℎ119882)
=
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12119882
119896minus12 119868
lowast
ℎVℎ)
minus int
119905119899minus12
0
119861 (119905119899 119904119882 (119904) 119868
lowast
ℎVℎ) 119889119904
le 1198621198962int
119905119899
0
1003817100381710038171003817(119861ℎ119882)
119904119904
1003817100381710038171003817 119889119904
le 1198621198962int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172) 119889119904
119896
119873
sum
119899=1
10038171003817100381710038171199031198991003817100381710038171003817 le 119862ℎ
2int
119905119899
0
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
+ 1198621198962int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172+10038171003817100381710038171003817119906(3)10038171003817100381710038171003817
) 119889119904
(105)
Taking Vℎ= 120579
119899minus12 in (101) and noting that (120597120579119899 119868lowastℎ120579119899minus12
) =
(12)120597|||120579119899|||
2 there is1003816100381610038161003816
1003816100381610038161003816
10038161003816100381610038161205791198991003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816
2
minus10038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus110038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
+ 211989611988810038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus1210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
1
le 1198621198962
119899
sum
119896=1
10038171003817100381710038171003817120579119896minus12100381710038171003817100381710038171
10038171003817100381710038171003817120579119899minus12100381710038171003817100381710038171
+ 1198621198961003817100381710038171003817119903119899
1003817100381710038171003817
10038171003817100381710038171003817120579119899minus1210038171003817100381710038171003817
le11989611988810038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus1210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
1+ 119862119896
2
119899
sum
119896=1
10038171003817100381710038171003817120579119896minus1210038171003817100381710038171003817
2
1+ 119862119896
10038171003817100381710038171199031198991003817100381710038171003817
10038171003817100381710038171003817120579119899minus1210038171003817100381710038171003817
(106)
Summing from 119899 = 1 to 119873 and then after cancelling thecommon factor and using Gronwallrsquos lemma we obtain
10038161003816100381610038161003816
10038161003816100381610038161003816
1003816100381610038161003816100381612057911987310038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
le 11986210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579010038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
+ 119862119896
119873
sum
119896=1
10038171003817100381710038171199031198991003817100381710038171003817 (
1003817100381710038171003817100381712057911989610038171003817100381710038171003817
+10038171003817100381710038171003817120579119896minus1210038171003817100381710038171003817
) (107)
and then
10038161003816100381610038161003816
10038161003816100381610038161003816
1003816100381610038161003816100381612057911987310038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816le 119862
10038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579010038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816+ 119862119896
119873
sum
119899=1
10038171003817100381710038171199031198991003817100381710038171003817
(108)
the theorem follows from the estimates of 120588119899 and 119903119899
References
[1] Z Q Cai ldquoOn the finite volume element methodrdquo NumerischeMathematik vol 58 no 7 pp 713ndash735 1991
[2] S H Chou and D Y Kwak ldquoAnalysis and convergence of aMAC-like scheme for the generalized Stokes problemrdquo Numer-ical Methods for Partial Differential Equations vol 13 no 2 pp147ndash162 1997
[3] P Chatzipantelidis ldquoA finite volume method based on theCrouzeix-Raviart element for elliptic PDErsquos in two dimensionsrdquoNumerische Mathematik vol 82 no 3 pp 409ndash432 1999
[4] P Chatzipantelidis ldquoFinite volumemethods for elliptic PDErsquos anew approachrdquo Mathematical Modelling and Numerical Analy-sis vol 36 no 2 pp 307ndash324 2002
[5] P Chatzipantelidis R D Lazarov and V Thomee ldquoErrorestimates for a finite volume element method for parabolicequations in convex polygonal domainsrdquoNumericalMethods forPartial Differential Equations vol 20 no 5 pp 650ndash674 2004
[6] R E Ewing R D Lazarov and Y Lin ldquoFinite volume elementapproximations of nonlocal in time one-dimensional flows inporous mediardquo Computing vol 64 no 2 pp 157ndash182 2000
[7] R Ewing R Lazarov and Y Lin ldquoFinite volume elementapproximations of nonlocal reactive flows in porous mediardquoNumericalMethods for Partial Differential Equations vol 16 no3 pp 285ndash311 2000
[8] R E Ewing T Lin andY Lin ldquoOn the accuracy of the finite vol-ume element method based on piecewise linear polynomialsrdquoSIAM Journal on Numerical Analysis vol 39 no 6 pp 1865ndash1888 2002
[9] R K Sinha and J Geiser ldquoError estimates for finite volumeelement methods for convection-diffusion-reaction equationsrdquoApplied Numerical Mathematics vol 57 no 1 pp 59ndash72 2007
[10] S H Chou ldquoAnalysis and convergence of a covolume methodfor the generalized Stokes problemrdquo Mathematics of Computa-tion vol 66 no 217 pp 85ndash104 1997
[11] M Berggren ldquoA vertex-centered dual discontinuous Galerkinmethodrdquo Journal of Computational and Applied Mathematicsvol 192 no 1 pp 175ndash181 2006
[12] S H Chou and D Y Kwak ldquoMultigrid algorithms for a vertex-centered covolume method for elliptic problemsrdquo NumerischeMathematik vol 90 no 3 pp 441ndash458 2002
[13] R Eymard T Gallouet and R Herbin Finite Volume MethodsHandbook of Numerical Analysis North-Holland AmsterdamThe Netherlands 2000
[14] V R Voller Basic Control Volume Finite Element Methods forFluids and Solids World Scientific Publishing 2009
[15] J Huang and S Xi ldquoOn the finite volume element method forgeneral self-adjoint elliptic problemsrdquo SIAM Journal on Numer-ical Analysis vol 35 no 5 pp 1762ndash1774 1998
[16] X Ma S Shu and A Zhou ldquoSymmetric finite volume discreti-zations for parabolic problemsrdquo Computer Methods in AppliedMechanics and Engineering vol 192 no 39-40 pp 4467ndash44852003
[17] R D Lazarov and S Z Tomov ldquoAdaptive finite volume elementmethod for convection-diffusion-reaction problems in 3-Drdquo inScientific Computing and Applications vol 7 of Advances inComputation Theory and Practice pp 91ndash106 Nova SciencePublishers Huntington NY USA 2001
[18] I DMishevFinite volume and finite volume elementmethods fornon-symmetric problems [PhD thesis] Texas AampM University1997 Technical Report ISC-96-04-MATH
Journal of Mathematics 13
[19] C Chen and T Shih Finite Element Methods for Integrodifferen-tial Equations World Scientific Publishing Singapore 1998
[20] Y P Lin V Thomee and L B Wahlbin ldquoRitz-Volterra pro-jections to finite-element spaces and applications to integrod-ifferential and related equationsrdquo SIAM Journal on NumericalAnalysis vol 28 no 4 pp 1047ndash1070 1991
[21] VThomeeGalerkin Finite Element Methods for Parabolic Prob-lems Springer Series in Computational Mathematics SpringerNew York NY USA 2006
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Differential EquationsInternational Journal of
Volume 2014
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Mathematical PhysicsAdvances in
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OptimizationJournal of
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CombinatoricsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Function Spaces
Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of Mathematics and Mathematical Sciences
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Algebra
Discrete Dynamics in Nature and Society
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Decision SciencesAdvances in
Discrete MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
Volume 2014 Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Stochastic AnalysisInternational Journal of
Journal of Mathematics 3
z
Vz
(a)
z
K
Kz
zK
(b)
Figure 1 (a) A sample region with blue lines indicating the corresponding control volume 119881119911 (b) A triangle 119870 partitioned into three
subregions119870119911
Kz
qs1 qs2
qe
zK
z
Figure 2 A tetrahedron 119870 partitioned into twelve subregions119870119911
22 Construction of the FVE Scheme We formulate the FVEmethod for the problem (1) as follows Given a 119911 isin 119885
0
ℎ
integrating (1)1 over the associated control volume 119881119911and
applying Greenrsquos formula we obtain an integral conservationas follows form
int119881119911
119906119905minus int
120597119881119911
119860 (119909 119905) nabla119906 sdot 119899119889119904 minus int120597119881119911
119861 (119909 119905 119904) nabla119906 sdot 119899119889119904
= int119881119911
119891 (119909 119905)
(8)
where 119899 denotes the unit outer normal vector to 120597119881119911
Let 119868lowastℎ C(Ω) rarr 119878
lowast
ℎbe the transfer operator defined by
119868lowast
ℎV = sum
119911isin1198850
ℎ
V (119911) 120594119911 forallV isin 119878
ℎ (9)
where
119878lowast
ℎ= V isin 119871
2(Ω) V
119894
1003816100381610038161003816119881119911is constant forall119911 isin 119885
0
ℎ (10)
and 120594119911is the characteristic function of the control volume119881
119911
Now for 119905 gt 0 and for an arbitrary 119868lowastℎV we multiply (8)
by V(119911) and sum over all 119911 isin 1198850
ℎ Then the semidiscrete FVE
approximation119906ℎof (1) is a solution to the following problem
find 119906ℎ(119905) isin 119878
ℎfor 119905 gt 0 such that
(119906ℎ119905 V
ℎ) + 119860 (119905 119906
ℎ V
ℎ) + int
119905
0
119861 (119905 119904 119906ℎ(119904) V
ℎ) 119889119904
= (119891 Vℎ) V
ℎisin 119878
lowast
ℎ
119906ℎ(0) = 119906
0ℎisin 119878
ℎ
(11)
Here the bilinear forms 119860(119905 119906 V) and 119861(119905 119904 119906 V) aredefined by
119860(119905 119906 V)
=
minussum
119911isin1198850
ℎ
V119894 int120597119881119911
119860(119909 119905) nabla119906 sdot 119899119889119904 (119906 V) isin ((1198671
0cap 1198672) cup 119878ℎ) times 119878
lowast
ℎ
int
Ω
119860(119909) nabla119906 sdot nablaV119889119909 (119906 V) isin 1198671
0times 1198671
0
119861 (119905 119904 119906 V)
=
minussum
119911isin1198850
ℎ
V119911 int120597119881119911
119861 (119909 119905 119904) nabla119906 sdot 119899119889119904 (119906 V) isin ((1198671
0cap 1198672) cup 119878ℎ) times 119878
lowast
ℎ
int
Ω
119861 (119909 119905 119904) nabla119906 sdot nablaV119889119909 (119906 V) isin 1198671
0times 1198671
0
(12)
Let
119906ℎ=
119873ℎ
sum
119895=1
120572119911(119905) 120593
119911(119909)
120572 (119905) = (1205721(119905) 120572
2(119905) 120572
119873ℎ(119905))
119879
(13)
Then we can rewrite scheme (11)1 as systems of ordinarydifferential equations as follows
119872ℎ1205721015840(119905) + 119860
ℎ(119905) 120572 (119905) + int
119905
0
119861ℎ(119905 119904) 120572 (119904) 119889119904 = 119865
ℎ(119905) (14)
4 Journal of Mathematics
z
Vz
(a)
z
K
Kz
zK
(b)
Figure 3 119911119870is the barycenter of 119870 and 119902
119890is to be the midpoint of the edge 119890
Kz
zK
z
Figure 4 119902119890is the midpoint of the edge 119890 and 119902
119878119894is the barycenter
of the face 119878119894
Here 119865ℎ(119905) = (119891
1(119905) 119891
2(119905) 119891
119873ℎ(119905))
119879 the mass matrix119872
ℎ= 119872
ℎ119894119895 = (120593
119894 120594
119895) is tridiagonal and both 119860
ℎ(119905) =
119860(119905 120593119894 120594
119895) and 119861
ℎ(119905 119904) = 119861(119905 119904 120593
119894 120594
119895) are positive
definitesIn order to describe features of the bilinear forms defined
in (11) we introduce some discrete norms on 119878ℎin the same
way as in [7]1003817100381710038171003817Vℎ
1003817100381710038171003817
2
0ℎ= (V
ℎ V
ℎ)0ℎ
= (119868lowast
ℎVℎ 119868
lowast
ℎVℎ)
1003816100381610038161003816Vℎ1003816100381610038161003816
2
1ℎ= sum
119909119894isin1198850
ℎ
sum
119909119895isinΠ(119894)
meas (119881119894) (
V119894minus V
119895
119889119894119895
)
2
1003817100381710038171003817Vℎ1003817100381710038171003817
2
1ℎ=1003817100381710038171003817Vℎ
1003817100381710038171003817
2
0ℎ+1003816100381610038161003816Vℎ
1003816100381610038161003816
2
1ℎ
1003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816Vℎ1003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816
2
= (Vℎ 119868
lowast
ℎVℎ)
(15)
where 119889119894119895
= 119889(119909119894 119909
119895) the distance between 119909
119894and 119909
119895
Obviously these norms are well defined for Vℎisin 119878
lowast
ℎas well
and Vℎ0ℎ
= |||Vℎ|||
Hereafter we state the equivalence of discrete norms sdot
0ℎand sdot
1ℎwith usual norms sdot and sdot
1on 119878
ℎ
respectively
Lemma 1 (see [7]) There exist two positive constants 1198620and
1198621such that for all V
ℎisin 119878
ℎ we have
1198620
1003817100381710038171003817Vℎ10038171003817100381710038170ℎ
le1003817100381710038171003817Vℎ
1003817100381710038171003817 le 1198621
1003817100381710038171003817Vℎ10038171003817100381710038170ℎ
forallVℎisin 119878
ℎ
1198620
1003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816Vℎ1003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816 le1003817100381710038171003817Vℎ
1003817100381710038171003817 le 1198621
1003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816Vℎ1003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816 forallVℎisin 119878
ℎ
1198620
1003817100381710038171003817Vℎ10038171003817100381710038171ℎ
le1003817100381710038171003817Vℎ
10038171003817100381710038171le 119862
1
1003817100381710038171003817Vℎ10038171003817100381710038171ℎ
forallVℎisin 119878
ℎ
(16)
Next we recall some properties of the bilinear forms (see[7 18])
Lemma 2 (see [7]) There exist two positive constants 119862 and119862
0such that for all 119906
ℎ V
ℎisin 119878
ℎ we have
119860 (119906ℎ 119868
lowast
ℎVℎ) le 119862
1003817100381710038171003817119906ℎ
10038171003817100381710038171
1003817100381710038171003817Vℎ10038171003817100381710038171 forall119906
ℎ V
ℎisin 119878
ℎ
119860 (Vℎ 119868
lowast
ℎVℎ) ge 119862
0
1003817100381710038171003817Vℎ1003817100381710038171003817
2
1 forallV
ℎisin 119878
ℎ
(17)
The following lemmas are proved in [3 7] which give thekey feature of the bilinear forms in the FVE method
Lemma 3 (see [3]) Assume that 120593 isin 1198821119901
0 Then one has
119860 (119905 120593 Vℎ) minus 119860 (119905 120593 119868
lowast
ℎVℎ)
= sum
119870isin120591ℎ
int120597119870
(119860 (119905) nabla120593 sdot n) (Vℎminus 119868
lowast
ℎVℎ) 119889119904
minus sum
119870isin120591ℎ
int119870
(nabla sdot 119860 (119905) nabla120593) (Vℎminus 119868
lowast
ℎVℎ) 119889119904 forallV
ℎisin 119878
ℎ
(18)
The aforementioned identity holds true when 119860(sdot sdot) is replacedby 119861(119905 119904 sdot sdot)
Lemma 4 (see [3]) Assume that 120593 isin 119878ℎ Then one has
119860 (119905 120593 120594) minus 119860 (119905 120593 119868lowast
ℎ120594) le 119862ℎ
100381610038161003816100381612059310038161003816100381610038161119901
100381610038161003816100381612059410038161003816100381610038161119902
(19)
Furthermore for 120593 isin 1198821119901
0cap119882
2119901 we have
119860 (119905 120593 120594) minus 119860 (119905 120593 119868lowast
ℎ120594) le 119862ℎ
100381710038171003817100381712059310038171003817100381710038172119901
100381710038171003817100381712059410038171003817100381710038171119902
(20)
Journal of Mathematics 5
3 Ritz-Volterra Projection andRelated Estimates
Following [7 19 20] we define the Ritz-Volterra projection119881ℎ(119905) 119867
1
0rarr 119878
ℎas follows
119860 (119905 119906 minus 119881ℎ119906 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 119906 (119904) minus 119881ℎ119906 (119904) 119868
lowast
ℎVℎ) 119889119904 = 0
119905 gt 0 forallVℎisin 119878
ℎ
(21)
This 119881ℎ(119905) is an elliptic projection with memory of 119906
into 119878lowast
ℎ It is easy to see that (21) is actually a system of
integral equations of Volterra type In fact if 119881ℎ(119905)119906 =
sum119873ℎ
119895=1120572119895(119905)120593
119895(119909) then (21) can be rewritten as
119860ℎ(119905) 120572 (119905) + int
119905
0
119861ℎ(119905 119904) 120572 (119904) 119889119904 = 119865
ℎ(119905) (22)
where 119860ℎ(119905) 119861
ℎ(119905 119904) are matrices and 120572(119905) 119865
ℎ(119905) are vectors
defined via
120572 (119905) = (1205721(119905) 120572
2(119905) 120572
119873ℎ(119905))
119879
119865ℎ119896(119905) = 119860 (119905 119906 120594
119896) + int
119905
0
119861 (119905 119904 119906 (119904) 120594119896) 119889119904
119896 = 1 2 119873ℎ
119860ℎ(119905) = 119860 (119905 120593
119896(119909) 120594
119897) 119861
ℎ(119905 119904) = 119861 (119905 119904 120593
119896(119909) 120594
119897)
(23)
From the positivity of 119860 (Lemma 2) and the linearity of(22) we see that the system (22) possesses a unique solution120572(119905) Consequently 119881
ℎ(119905)119906 in (21) is well defined
Set 120588 = 119906 minus 119881ℎ(119905)119906 The following lemma was proved in
[7] which shows the1198671 error estimate for 120588 and its temporalderivative
Lemma 5 (see [7]) Assume that 119863119899
119905119906 isin 119871
infin(119867
1
0cap 119867
2) for all
0 le 119899 le 119896 for some integer 119896 ge 0 Then for 119879 gt 0 fixed thereis a constant 119862 = 119862(119879 119896) gt 0 independent of ℎ and 119906 suchthat for all 0 le 119899 le 119896 and 0 lt 119905 lt 119879
1003817100381710038171003817120588 (119905)10038171003817100381710038171
le 119862ℎ(1199062 + int
119905
0
1199062119889119904)
1003817100381710038171003817119863119899
119905120588 (119905)
10038171003817100381710038171le 119862ℎ(
119899
sum
119894=0
10038171003817100381710038171003817119863
119894
119905119906100381710038171003817100381710038172
+ int
119905
0
1199062119889119904)
(24)
Now we establish 1198712 error estimate for 120588 and its temporalderivative which improves Theorem 22 in [7] This estimateis optimal with respect to the order
Lemma 6 Assume that for some integer 119896 ge 0 119863119899
119905119906 isin
119871infin(119867
1
0cap 119867
2) for all 0 le 119899 le 119896 Then for 119879 gt 0 fixed there is
a constant 119862 = 119862(119879 119896) gt 0 independent of ℎ and 119906 such thatfor all 0 le 119899 le 119896 and 0 lt 119905 lt 119879
1003817100381710038171003817120588 (119905)1003817100381710038171003817 le 119862ℎ
2(1199062 + int
119905
0
1199062119889119904)
1003817100381710038171003817119863119899
119905120588 (119905)
1003817100381710038171003817 le 119862ℎ2(
119899
sum
119894=0
10038171003817100381710038171003817119863
119894
119905119906100381710038171003817100381710038172
+ int
119905
0
1199062119889119904)
(25)
Proof The proof will proceed by duality argument Let 120595 isin
1198672(Ω) cap 119867
1
0(Ω) be the solution of
119860lowast(119905) 120595 = 120588 in Ω
120595 = 0 in 120597Ω
(26)
The solution 120595 isin 1198672(Ω) cap 119867
1
0(Ω) satisfies the following
regularity estimate1003817100381710038171003817120595
10038171003817100381710038172le 119862
10038171003817100381710038171205881003817100381710038171003817 (27)
Multiplying this equation by 120588 and then taking 1198712 innerprod-uct overΩ we obtain the following
10038171003817100381710038171205881003817100381710038171003817
2
= 119860 (119905 120588 120595)
= 119860 (119905 120588 120595 minus 119877ℎ120595) + 119860 (119905 120588 119877
ℎ120595 minus 119868
lowast
ℎ(119877
ℎ120595))
minus int
119905
0
119861 (119905 119904 120588 (119904) 119868lowast
ℎ119877ℎ120595 minus 119877
ℎ120595) 119889119904
minus int
119905
0
119861 (119905 119904 120588 (119904) 119877ℎ120595 minus 120595) 119889119904
minus int
119905
0
119861 (119905 119904 120588 (119904) 120595) 119889119904 = 1198681+ 119868
2+ 119868
3+ 119868
4+ 119868
5
(28)
We have
100381610038161003816100381611986811003816100381610038161003816 +
100381610038161003816100381611986841003816100381610038161003816 le 119862ℎ
2(1199062 + int
119905
0
1199062119889119904)1003817100381710038171003817120595
10038171003817100381710038172 (29)
Applying Lemma 4 we obtain
100381610038161003816100381611986821003816100381610038161003816 +
100381610038161003816100381611986831003816100381610038161003816 le 119862ℎ
2(1199062 + int
119905
0
1199062119889119904)1003817100381710038171003817120595
10038171003817100381710038172 (30)
Finally we have
100381610038161003816100381611986851003816100381610038161003816 le int
119905
0
(120588 (119904) 119861lowast(119905 119904) 120595) 119889119904 le 119862(int
119905
0
10038171003817100381710038171205881003817100381710038171003817 119889119904)
100381710038171003817100381712059510038171003817100381710038172 (31)
then we have
10038171003817100381710038171205881003817100381710038171003817 le 119862ℎ
2(1199062 + int
119905
0
1199062119889119904) + 119862(int
119905
0
10038171003817100381710038171205881003817100381710038171003817 119889119904) (32)
Finally an application of Gronwallrsquos lemma yields the firstestimate
The second inequality follows in a similar fashion
6 Journal of Mathematics
Lemma7 There exists a constant119862 independent of ℎ such that
100381710038171003817100381712058810038171003817100381710038170119901
+ ℎ100381710038171003817100381712058810038171003817100381710038171119901
le 119862ℎ2(1199062119901 + int
119905
0
1199062119901119889119904) (33)
Proof Let 120588119909be an arbitrary component of nabla120588 with 119901 and
119902 conjugate indices we have 120588119909119901
= sup(120588119909 120593) 120593 isin
Cinfin
0(Ω) 120593
119902= 1
For any such 120593 let 120595 be the solution of
119860lowast(119905 120595 V) = minus (120593
119909 V) forallV isin 119867
1
0(Ω)
120595 = 0 on 120597Ω
(34)
It follows from the regularity theory for the elliptic problemthat
100381710038171003817100381712059510038171003817100381710038171119902
le 119862119901
10038171003817100381710038171205931003817100381710038171003817119902
= 119862119901 (35)
We then have by application of (21) that
(120588119909 120593) = 119860 (119905 120588 120595) = 119860 (119905 120588 120595 minus 119877
ℎ120595)
+ 119860 (119905 120588 119877ℎ120595 minus 119868
lowast
ℎ(119877
ℎ120595))
+ int
119905
0
119861 (119905 119904 120588 (119904) 119868lowast
ℎ(119877
ℎ120595)) 119889119904
= 1198681+ 119868
2+ 119868
3
119860 (119905 120588 120595 minus 119877ℎ120595) = 119860 (119905 119877
ℎ119906 minus 119906 120595)
= minus ((119877ℎ119906 minus 119906)
119909 120593) le 119862ℎ1199062119901
(36)
Applying Lemma 4 we have
1198682= 119860 (119905 119906 119877
ℎ120595 minus 119868
lowast
ℎ(119877
ℎ120595)) minus 119860 (119905 119881
ℎ119906 119877
ℎ120595 minus 119868
lowast
ℎ(119877
ℎ120595))
le 119862ℎ1199062119901
(37)
Finally 1198683is estimated as follows
1198683= int
119905
0
119861 (119905 119904 120588 (119904) 119868lowast
ℎ(119877
ℎ120595)) 119889119904 le 119862
119901int
119905
0
100381710038171003817100381712058810038171003817100381710038171119901
119889119904 (38)
Combining these estimates we get
100381710038171003817100381712058810038171003817100381710038171119901
le 119862ℎ1199062119901 + 119862119901int
119905
0
100381710038171003817100381712058810038171003817100381710038171119901
119889119904 (39)
hence by Gronwallrsquos lemma
100381710038171003817100381712058810038171003817100381710038171119901
le 119862ℎ(1199062119901 + int
119905
0
1199062119901119889119904) (40)
The derivation of the error estimate in 119871119901 is similar to the casewhen 119901 = 2
4 Error Estimates forSemidiscrete Approximations
We split the error 119890(119905) = 119906(119905) minus 119906ℎ(119905) as follows
119890 (119905) = (119906 (119905) minus 119881ℎ119906 (119905)) + (119881
ℎ119906 (119905) minus 119906
ℎ(119905)) = 120588 + 120579 (41)
It is easy to see that 120579 = 119881ℎ119906(119905) minus 119906
ℎ(119905) isin 119878
ℎsatisfies an
error equation of the form
(120579119905 119868
lowast
ℎVℎ) + 119860 (119905 120579 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎVℎ) 119889119904
= minus (120588119905 119868
lowast
ℎVℎ) V
ℎisin 119878
ℎ
(42)
Since the estimates of 120588 are already known it is enoughto have estimates for 120579
We will prove a sequence of lemmas which lead to thefollowing result
Lemma8 There is a positive constant119862 independent of ℎ suchthat
|||120579 (119905)||| le 119862(|||120579 (0)|||2+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817 119889119904) (43)
Proof Since 120579 isin 119878ℎwe may take V
ℎ= 120579 in (42) to obtain
1
2
119889
119889119905|||120579 (119905)|||
2+ 119888120579
2
1le
10038171003817100381710038171205881199051003817100381710038171003817 120579 + 119862int
119905
0
12057911198891199041205791
le1003817100381710038171003817120588119905
1003817100381710038171003817 120579 +1
2119888120579
2
1+ 119862int
119905
0
1205792
1119889119904
(44)
and hence by integration and Lemma 1 we have
||120579 (119905)||2+ int
119905
0
1205792
1119889119904
le 119862(|||120579 (0)|||2+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817 120579 119889119904 + int
119905
0
int
119904
0
120579 (120591)2
1119889120591119889119904)
(45)
Gronwallrsquos lemma now implies the following
|||120579 (119905)|||2+ int
119905
0
1205792
1119889119904 le 119862(|||120579 (0)|||
2+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817 120579 119889119904)
le 119862|||120579 (0)|||2+1
2sup119904le119905
120579 (119904)2
+ (int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817 119889119904)
2
(46)
Since this holds for all isin 119869 we may conclude that
||120579 (119905)|| le 119862(|||120579 (0)||| + int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817 119889119904) (47)
Journal of Mathematics 7
Remark 9 If the initial value was chosen so that 1199060ℎminus 119906
0 le
119862ℎ2119906
02 then 120579(0) le 119906
0ℎminus119906
0+119881
ℎ1199060minus119906
0 le 119862ℎ
2119906
02
One can derive
|||120579 (119905)||| le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (48)
Lemma 10 There is a positive constant 119862 independent of ℎsuch that
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
119889119904 + 1205792
1le 119862(120579 (0)
2
1+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
2
119889119904) (49)
Proof Set Vℎ= 120579
119905in (42) to get
10038171003817100381710038171205791199051003817100381710038171003817
2
+1
2
119889
119889119905119860 (119905 120579 119868
lowast
ℎ120579)
= minus (120588119905 119868
lowast
ℎ120579119905) minus int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579119905(119905)) 119889119904
+1
2119860
119905(119905 120579 119868
lowast
ℎ120579)
+1
2[119860 (119905 120579
119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)]
le1
2
10038171003817100381710038171205881199051003817100381710038171003817
2
+1
2
1003816100381610038161003816
1003816100381610038161003816
10038161003816100381610038161205791199051003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816
2
+ 119860119905(119905 120579 119868
lowast
ℎ120579)
+1
2[119860 (119905 120579
119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)]
minus119889
119889119905int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579 (119905)) 119889119904
+ 119861 (119905 119905 120579 (119905) 119868lowast
ℎ120579 (119905)) + int
119905
0
119861119905(119905 119904 120579 (119904) 119868
lowast
ℎ120579 (119905)) 119889119904
(50)
Then
10038171003817100381710038171205791199051003817100381710038171003817
2
+119889
119889119905119860 (119905 120579 119868
lowast
ℎ120579)
le1003817100381710038171003817120588119905
1003817100381710038171003817
2
minus119889
119889119905int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579) 119889119904
+ 119862(1205792
1+ int
119905
0
120579 (119904)2
1119889119904)
+1
2[119860 (119905 120579
119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)]
(51)
In addition recall that
119860 (119905 119906ℎ 119868
lowast
ℎVℎ) minus 119860 (119905 V
ℎ 119868
lowast
ℎ119906ℎ) le 119862ℎ
1003817100381710038171003817119906ℎ
10038171003817100381710038171
1003817100381710038171003817Vℎ10038171003817100381710038171
forall119906ℎ V
ℎisin 119878
ℎ
(52)
then applying an inverse inequality and using kickbackargument we obtain
[119860 (119905 120579119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)] le 119862ℎ
100381710038171003817100381712057911990510038171003817100381710038171
1205791 le 1198621003817100381710038171003817120579119905
1003817100381710038171003817 1205791
le 1205761003817100381710038171003817120579119905
1003817100381710038171003817
2
+ 1198621205792
1
(53)
Combining these estimates we derive
10038171003817100381710038171205791199051003817100381710038171003817
2
+119889
119889119905119860 (119905 120579 119868
lowast
ℎ120579)
le1003817100381710038171003817120588119905
1003817100381710038171003817
2
minus119889
119889119905int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579) 119889119904
+ 119862(1205792
1+ int
119905
0
120579 (119904)2
1119889119904)
(54)
So after integration in time and using the weak coercivity of119860(119905 120579 119868
lowast
ℎ120579) we get
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
119889119904 + 1198880120579
2
1
le 1198880120579 (0)
2
1+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
2
119889119904
+ int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579) 119889119904 + 119862int
119905
0
120579 (119904)2
1119889119904
le 1198880120579 (0)
2
1+119888
2120579
2
1+ 119862(int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
2
+ 120579 (119904)2
1119889119904)
(55)
and by Gronwallrsquos lemma
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
119889119904 + 1198881205792
1le 119862(120579 (0)
2
1+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
2
119889119904) (56)
Remark 11 If 120579(0) = 0 then
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
119889119904 + 1198881205792
1le 119862ℎ
2(int
119905
0
1003817100381710038171003817119906119905
1003817100381710038171003817
2
2119889119904) (57)
Theorem 12 (error estimates in 1198712 and1198671-norms) Let 119906 119906
ℎ
be the solutions of (2) and (11) respectively Assume that 119906 119906119905isin
119871infin(119867
1
0cap 119867
2)
(a) Let 1199060ℎ
be chosen so that 1199060ℎ
minus 1199060 le 119862ℎ
2119906
02
Then for 119879 gt 0 fixed there is a constant 119862 = 119862(119879)
independent of ℎ such that for all 0 lt 119905 lt 119879
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905)
1003817100381710038171003817 le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (58)
(b) Let 1199060ℎ
be chosen so that 1199060ℎminus 119906
01
le 119862ℎ11990602
Then for 119879 gt 0 fixed there is a constant 119862 = 119862(119879)
independent of ℎ such that for all 0 lt 119905 lt 119879
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905))
10038171003817100381710038171le 119862ℎ(
10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (59)
We now prove error estimates for FVE approximations in119871119901 and119882
1119901-norms
8 Journal of Mathematics
Theorem 13 (error estimates in 119871119901 and 119882
1119901-norms) Let119906 119906
ℎbe the solutions of (2) and (11) respectively and 119906
0ℎ=
119881ℎ1199060 Assume that 119906 119906
119905isin 119871
infin(119867
1
0cap 119882
2119901) For ℎ sufficiently
small we have
1003817100381710038171003817119906 minus 119906ℎ
10038171003817100381710038170119901le 119862ℎ
2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
1003817100381710038171003817119906 minus 119906ℎ
10038171003817100381710038171119901le 119862ℎ(
10038171003817100381710038171199060
10038171003817100381710038172+ 1199062119901 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
(60)
Proof If 2 le 119901 lt infin by the following Sobolev embeddinginequality
1205790119901 le 1198621205791 (61)
then the first desired estimate follows from Lemmas 7 and 10Given 120593 isin Cinfin
0(Ω) find 120595 isin 119867
1
0(Ω) such that
119860(119905)lowast120595 = minus120593
119909 in Ω
120595 = 0 on 120597Ω
100381710038171003817100381712059510038171003817100381710038171119902
le100381710038171003817100381712059310038171003817100381710038170119902
(62)
We have
((119906 minus 119906ℎ)119909 120593) = 119860 (119905 119906 minus 119906
ℎ 120595) = 119860 (119905 119906 minus 119906
ℎ 120595 minus 119877
ℎ120595)
+ 119860 (119905 119906 minus 119906ℎ 119877
ℎ120595 minus 119868
lowast
ℎ119877ℎ120595)
minus int
119905
0
119861 (119905 119904 (119906 minus 119906ℎ) (119904) 119868
lowast
ℎ119877ℎ120595) 119889119904
minus ((119906 minus 119906ℎ)119905 119868
lowast
ℎ119877ℎ120595)
= 1198681+ 119868
2+ 119868
3+ 119868
4
100381610038161003816100381611986811003816100381610038161003816 le
1003816100381610038161003816119860 (119905 119906 minus 119877ℎ119906 120595)
1003816100381610038161003816 le 1198621003817100381710038171003817119906 minus 119877
ℎ11990610038171003817100381710038171119901
100381710038171003817100381712059510038171003817100381710038171119902
le 119862ℎ11990621199011003817100381710038171003817120595
10038171003817100381710038171119902
(63)
By Lemma 4
100381610038161003816100381611986821003816100381610038161003816 le 119860 (119905 119906 minus 119906
ℎ 119877
ℎ120595 minus 119868
lowast
ℎ119877ℎ120595)
le 119862ℎ (1003816100381610038161003816119906 minus 119906
ℎ
10038161003816100381610038161119901+ |119906|2119901)
100381710038171003817100381712059510038171003817100381710038171119902
100381610038161003816100381611986831003816100381610038161003816 le int
119905
0
1003817100381710038171003817119906 minus 119906ℎ
100381710038171003817100381711199011198891199041003817100381710038171003817120595
10038171003817100381710038171119902
100381610038161003816100381611986841003816100381610038161003816 le (
1003817100381710038171003817119906 minus 119906ℎ
1003817100381710038171003817)1003817100381710038171003817120595
1003817100381710038171003817 le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
100381710038171003817100381712059510038171003817100381710038171119902
(64)
where we have used the fact 120595 le 1205951119903 119903 gt 1 Combining
these estimates we get
1003816100381610038161003816((119906 minus 119906ℎ)119909 120593)
1003816100381610038161003816 le 119862ℎ(10038171003817100381710038171199060
10038171003817100381710038172+ 1199062119901 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
100381710038171003817100381712059510038171003817100381710038171119902
1003817100381710038171003817(119906 minus 119906ℎ)119909
10038171003817100381710038170119901= sup
((119906 minus 119906ℎ)119909 120593)
100381710038171003817100381712059310038171003817100381710038170119902
le 119862ℎ1003816100381610038161003816119906 minus 119906
ℎ
10038161003816100381610038161119901
+ 119862ℎ(10038171003817100381710038171199060
10038171003817100381710038172+ 1199062119901 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
(65)
Hence using the Poincare inequality we have for ℎ sufficientlysmall
1003817100381710038171003817119906 minus 119906ℎ
10038171003817100381710038171119901le 119862ℎ(
10038171003817100381710038171199060
10038171003817100381710038172+ 1199062119901 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (66)
We compare the relationship between covolume solutionand the Galerkin finite element solution
Corollary 14 Let ℎbe the finite element solution to (2) that
is
(ℎ119905 V
ℎ) + 119860 (119905
ℎ V
ℎ)
+ int
119905
0
119861 (119905 119904 ℎ(119904) V
ℎ) 119889119904 = (119891 V
ℎ) V
ℎisin 119878
ℎ
ℎ(0) = 119877
ℎ1199060
(67)
For ℎ sufficiently small we have
1003817100381710038171003817(ℎminus 119906
ℎ)10038171003817100381710038171119901
le 119862(
ℎ1003817100381710038171003817119906 minus 119906
ℎ
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus 119906
ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817
+int
119905
0
(1003817100381710038171003817(119906 minus 119906
ℎ) (119904)
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus
ℎ) (119904)
10038171003817100381710038171119901) 119889119904
)
le 119862 (119906) ℎ
(68)
Proof By (2) and (67)
((ℎminus 119906)
119905 V
ℎ) + 119860 (119905
ℎminus 119906 V
ℎ)
+ int
119905
0
119861 (119905 119904 (ℎminus 119906) (119904) V
ℎ) 119889119904 = 0 V
ℎisin 119878
ℎ
(69)
Consider the following auxiliary problem For any such 120593 let120595 be the solution of the following
119860(119905)lowast120595 = minus120593
119909 in Ω
120595 = 0 on 120597Ω
(70)
Journal of Mathematics 9
with1003817100381710038171003817120595
10038171003817100381710038171119902le100381710038171003817100381712059310038171003817100381710038170119902
((ℎminus 119906
ℎ)119909 120593)
= 119860 (119905 ℎminus 119906
ℎ 120595)
= 119860 (119905 ℎminus 119906
ℎ 120595 minus 119877
ℎ120595) + 119860 (119905 119906 minus 119906
ℎ 119877
ℎ120595)
minus 119860 (119905 119906 minus 119906ℎ 119868
lowast
ℎ119877ℎ120595) minus ((119906 minus 119906
ℎ)119905 119868
lowast
ℎ119877ℎ120595)
minus int
119905
0
119861 (119905 119904 (119906 minus 119906ℎ) (119904) 119868
lowast
ℎ119877ℎ120595) 119889119904
+ 119860 (119905 ℎminus 119906 119877
ℎ120595)
= [119860 (119905 119906 minus 119906ℎ 119877
ℎ120595) minus 119860 (119905 119906 minus 119906
ℎ 119868
lowast
ℎ119877ℎ120595)]
minus ((119906 minus 119906ℎ)119905 119868
lowast
ℎ119877ℎ120595) minus ((
ℎminus 119906)
119905 119877
ℎ120595)
minus int
119905
0
119861 (119905 119904 (119906 minus 119906ℎ) (119904) 119868
lowast
ℎ119877ℎ120595) 119889119904
minus int
119905
0
119861 (119905 119904 (ℎminus 119906) (119904) 119877
ℎ120595) 119889119904
= 1198681+ 119868
2+ 119868
3
(71)
On the other hand10038161003816100381610038161198681
1003816100381610038161003816 le 119862ℎ1003817100381710038171003817119906 minus 119906
ℎ
10038171003817100381710038171119901
100381710038171003817100381712059510038171003817100381710038171119902
100381610038161003816100381611986821003816100381610038161003816 le 119862 (
1003817100381710038171003817(119906 minus 119906ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817)1003817100381710038171003817120595
1003817100381710038171003817
le 119862 (1003817100381710038171003817(119906 minus 119906
ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817)1003817100381710038171003817120595
10038171003817100381710038171119902
(72)
where we have used the fact 120595 le 1205951119903 119903 gt 1
100381610038161003816100381611986831003816100381610038161003816 le int
119905
0
(1003817100381710038171003817(119906 minus 119906
ℎ) (119904)
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus
ℎ) (119904)
10038171003817100381710038171119901) 119889119904
100381710038171003817100381712059510038171003817100381710038171119902
1003817100381710038171003817(ℎminus 119906
ℎ)119909
10038171003817100381710038170119901
= sup120593isinCinfin0
((ℎminus 119906
ℎ)119909 120593)
100381710038171003817100381712059310038171003817100381710038170119902
le 119862(
ℎ1003817100381710038171003817119906 minus 119906
ℎ
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus 119906
ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817
+int
119905
0
(1003817100381710038171003817(119906 minus 119906
ℎ) (119904)
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus
ℎ) (119904)
10038171003817100381710038171119901) 119889119904
)
(73)
We deduce the result from the known finite element esti-mates
Remark 15 In order to estimate (119906 minus 119906ℎ)119905 by differentiating
(42) with respect to 119905 we obtain
(120579119905119905 119868
lowast
ℎVℎ) + 119860 (119905 120579
119905 119868
lowast
ℎVℎ) + 119860
119905(119905 120579
119905 119868
lowast
ℎVℎ)
+ 119861 (119905 119905 120579 119868lowast
ℎVℎ) + int
119905
0
119861119905(119905 119904 120579 (119904) 119868
lowast
ℎVℎ) 119889119904
= minus (120588119905119905 119868
lowast
ℎVℎ)
(74)
Setting Vℎ= 120579
119905 we obtain
1
2
119889
119889119905
1003816100381610038161003816
1003816100381610038161003816
10038161003816100381610038161205791199051003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816
2
+ 1198881003817100381710038171003817120579119905
1003817100381710038171003817
2
1le1003817100381710038171003817120588119905119905
1003817100381710038171003817
10038171003817100381710038171205791199051003817100381710038171003817
+1
21198881003817100381710038171003817120579119905
1003817100381710038171003817
2
1+ 119862120579
2
1+ int
119905
0
1205792
1119889119904
le1003817100381710038171003817120588119905119905
1003817100381710038171003817
10038171003817100381710038171205791199051003817100381710038171003817 +
1
21198881003817100381710038171003817120579119905
1003817100381710038171003817
2
1+ 119862int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
1119889119904
(75)
Using kickback argument integrating and applying Gron-wallrsquos lemma we deduce
10038171003817100381710038171205791199051003817100381710038171003817 le 119862(
1003817100381710038171003817120579119905 (0)1003817100381710038171003817 + int
119905
0
100381710038171003817100381712058811990511990510038171003817100381710038171119889119904)
le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+10038171003817100381710038171199061
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904)
(76)
5 The Lumped Mass Finite VolumeElement Method
In this section we restrict our study to the 2D case A simpleway to define the lumped mass scheme [21] is to replace themass matrix 119872
ℎin (14) by the diagonal matrix 119872
ℎobtained
by taking for its diagonal elements the numbers 119872ℎ119894119894
=
sum119873ℎ
119895=1119872
ℎ119894119895or by lumping all masses in one row into the
diagonal entryThismakes the inversion of thematrix in frontof1205721015840
(119905) a trivialityWewill therefore study thematrix problem
119872ℎ1205721015840(119905) + 119860
ℎ(119905) 120572 (119905) + int
119905
0
119861ℎ(119905 119904) 120572 (119904) 119889119904 = 119865
ℎ(119905) (77)
We know that the lumped mass method defined by (77)above is equivalent to
(119868lowast
ℎ119906ℎ119905 119868
lowast
ℎVℎ) + 119860 (119905 119906
ℎ 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 119906ℎ(119904) 119868
lowast
ℎVℎ) 119889119904
= (119891 119868lowast
ℎVℎ) V
ℎisin 119878
ℎ
(78)
Our alternative interpretation of this procedure will beto think of (77) as being obtained by evaluating the firstterm in (78) by numerical quadrature Let 119870 be a triangle ofthe triangulation 119879
ℎ let 119909
119895 119895 = 1 2 3 be its vertices and
consider the quadrature formula
119876119870ℎ
(119891) =1
3area119870
3
sum
119895=1
119891 (119909119895) ≃ int
119870
119891119889119909 (79)
We may then define the associated bilinear form in 119878ℎtimes
119878lowast
ℎ using the quadrature scheme by the following
(Vℎ 120578
ℎ)ℎ= sum
119870isin119879ℎ
119876119870ℎ
(Vℎ120578ℎ) = sum
119909119894isin119873119886
ℎ
Vℎ(119909
119894) 120578
ℎ(119909
119894)10038161003816100381610038161003816119881119909119894
10038161003816100381610038161003816
forallVℎisin 119878
ℎ 120578
ℎisin 119878
lowast
ℎ
(80)
10 Journal of Mathematics
We note that Vℎ2
ℎ= (V
ℎ 119868
lowast
ℎVℎ)ℎis a norm in 119878
ℎwhich is
equivalent to the 1198712-norm uniformly in ℎ that is there existtwo positive constants 119862
1and 119862
2such that for all V
ℎisin 119878
ℎ we
have
1198620
1003817100381710038171003817Vℎ1003817100381710038171003817 le
1003817100381710038171003817Vℎ1003817100381710038171003817ℎ
le 1198621
1003817100381710038171003817Vℎ1003817100381710038171003817 forallV
ℎisin 119878
ℎ (81)
We note that the aforementioned definition (Vℎ 120578
ℎ)ℎmay
be used also for 120578ℎisin 119878
ℎand that (V
ℎ 119908
ℎ)ℎ= (V
ℎ 119868
lowast
ℎ119908
ℎ)ℎfor
Vℎ 119908
ℎisin 119878
ℎ
The lumpedmass method defined by (78) is equivalent to
(119906ℎ119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 119906
ℎ 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 119906ℎ(119904) 119868
lowast
ℎVℎ) 119889119904
= (119891 119868lowast
ℎVℎ) V
ℎisin 119878
ℎ
(82)
We introduce the quadrature error
120576ℎ(V
ℎ 119908
ℎ) = (V
ℎ 119908
ℎ)ℎminus (V
ℎ 119908
ℎ) (83)
Lemma 16 (see [21]) Let Vℎ 119908
ℎisin 119878
ℎ Then
1003816100381610038161003816120576ℎ (Vℎ 119908ℎ)1003816100381610038161003816 le 119862ℎ
2 1003817100381710038171003817nablaVℎ1003817100381710038171003817
1003817100381710038171003817nabla119908ℎ
1003817100381710038171003817 (84)
Theorem 17 Let 119906ℎand 119906 be the solutions of (82) and (2)
respectively and assume 119906ℎ(0) = 119877
ℎ1199060 Then we have for the
error in the lumped mass semidiscrete method for 119905 ge 0 thefollowing
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905)
1003817100381710038171003817 le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ 1199062 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (85)
Proof In order to estimate 120579 we write
(120579119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 120579 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎVℎ) 119889119904
= (119906ℎ119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 119906
ℎ 119868
lowast
ℎVℎ)
+ int
119905
0
119861 (119905 119904 119906ℎ(119904) 119868
lowast
ℎVℎ) 119889119904
minus ((119881ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus 119860 (119905 119881
ℎ119906 119868
lowast
ℎVℎ)
minus int
119905
0
119861 (119905 119904 119881ℎ119906 (119904) 119868
lowast
ℎVℎ) 119889119904
= (119891 119868lowast
ℎVℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus 119860 (119905 119906 119868
lowast
ℎVℎ)
minus int
119905
0
119861 (119905 119904 119906 (119904) 119868lowast
ℎVℎ)
= (119906119905 119868
lowast
ℎVℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)ℎ
= minus (120588119905 119868
lowast
ℎVℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)ℎ+ ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
(86)
We rewrite
((119881ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
= ((119881ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus ((119881
ℎ119906)
119905 V
ℎ)
+ ((119881ℎ119906)
119905 V
ℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
= 120576ℎ((119881
ℎ119906)
119905 V
ℎ) + ((119881
ℎ119906)
119905 V
ℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
(120579119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 120579 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎVℎ) 119889119904
= minus (120588119905 119868
lowast
ℎVℎ) + 120576
ℎ((119881
ℎ119906)
119905 V
ℎ)
+ ((119881ℎ119906)
119905 V
ℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
(87)
Setting Vℎ= 120579 in (87) we obtain
1
2
119889
119889119905120579
2
ℎ+ 119888
01205792
1
le1003817100381710038171003817120588119905
1003817100381710038171003817 120579 +1
21198880120579
2
1+ 119862int
119905
0
1205792
1119889119904
+ 120576ℎ((119881
ℎ119906)
119905 120579) + ((119881
ℎ119906)
119905 120579) minus ((119881
ℎ119906)
119905 119868
lowast
ℎ120579)
(88)
Using Lemma 16 and the inverse estimate we get1003816100381610038161003816120576ℎ (119881ℎ
119906119905 120579)
1003816100381610038161003816 le 119862ℎ2 1003817100381710038171003817nabla(119881ℎ
119906)119905
1003817100381710038171003817 nabla120579
le 119862ℎ2 1003817100381710038171003817nabla119906119905
1003817100381710038171003817 nabla120579
le 119862ℎ1003817100381710038171003817nabla119906119905
1003817100381710038171003817 120579
(89)
we have1003816100381610038161003816((119881ℎ
119906)119905 120579) minus ((119881
ℎ119906)
119905 119868
lowast
ℎ120579)1003816100381610038161003816 le 119862ℎ
1003817100381710038171003817nabla119906119905
1003817100381710038171003817 120579 (90)
Using Youngrsquos inequality and Gronwallrsquos lemma to eliminate120579
1on the right-hand side and using integration in 119905 we get
the result
1
2
119889
119889119905120579
2
ℎ+ 119888
0 120579 le1003817100381710038171003817120588119905
1003817100381710038171003817 120579 + 119862ℎ1003817100381710038171003817nabla119906119905
1003817100381710038171003817 120579 (91)
Using Youngrsquos inequality to eliminate 120579 on the right handside it becomes
Using integration in 119905 we get the result
We will now show that the 1198671-norm error bound of
theorem remains valid for the lumped mass method (82)
Theorem 18 Let 119906ℎand 119906 be the solutions of (82) and (2)
respectively and assume
119906ℎ(0) = 119877
ℎ1199060
10038171003817100381710038171199061ℎ(0) minus 119906
1
1003817100381710038171003817 le 119862ℎ210038171003817100381710038171199061
10038171003817100381710038172 (92)
Then we have for the error in the lumped mass semidiscretemethod for 119905 ge 0 the following
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905)
10038171003817100381710038171le 119862ℎ
2(10038171003817100381710038171199060
10038171003817100381710038172+10038171003817100381710038171199061
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904)
(93)
Journal of Mathematics 11
Proof Setting Vℎ= 120579
119905in (87) we obtain
10038171003817100381710038171205791199051003817100381710038171003817
2
ℎ+1
2
119889
119889119905119860 (119905 120579 119868
lowast
ℎ120579)
=1
2119860
119905(119905 120579 119868
lowast
ℎ120579) +
1
2[119860 (119905 120579
119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)]
119861 (119905 119905 120579 (119905) 119868lowast
ℎ120579 (119905)) + int
119905
0
119861119905(119905 119904 120579 (119904) 119868
lowast
ℎ120579 (119905)) 119889119904
minus119889
119889119905int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579 (119905)) 119889119904 minus (120588
119905 119868
lowast
ℎ120579119905)
minus 120576ℎ((119881
ℎ119906)
119905 120579
119905) + ((119881
ℎ119906)
119905 120579) minus ((119881
ℎ119906)
119905 119868
lowast
ℎ120579)
(94)
It follows thus that using integration in 119905 and Gronwallrsquoslemma we have
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
ℎ+ 120579
2
1le 119862nabla120579 (0)
2+ 119862int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
10038171003817100381710038171205791199051003817100381710038171003817 119889119904
+ 119862ℎ2int
119905
0
1003817100381710038171003817119906119905
1003817100381710038171003817
2
1119889119904
(95)
6 Full Discretization
Let 120597119880119899= (119880
119899minus119880
119899minus1)119896 be the backward difference quotient
of 119880119899 assume that 119860ℎ
= 119875ℎ119860 is a discrete analogue of 119860
(similarly 119861ℎ
= 119875ℎ119861) where 119875
ℎ 119871
2(Ω) rarr 119878
lowast
ℎthe 119871
2
projection is defined by
(119875ℎV 119868lowast
ℎVℎ) = (V 119868lowast
ℎVℎ) V isin 119871
2(Ω) V
ℎisin 119878
ℎ (96)
In order to define fully discrete approximation of (11) wediscretize the time by taking 119905
119899= 119899119896 119896 gt 0 119899 = 1 2 and
use the numerical quadrature
int
119905119899minus12
0
119892 (119904) 119889119904 asymp
119899
sum
119896=1
120596119899119896119892 (119905
119896minus12) 119905
119899minus12= (119899 minus
1
2) 119896
(97)
Here 120596119899119896 are the integrationweights andwe assume that
the following error estimate is valid
119902119899(119892) = int
119905119899minus12
0
119892 (119904) 119889119904minus
119899
sum
119896=1
120596119899119896119892 (119905
119896minus12)
le 1198621198962int
119905119899
0
(10038161003816100381610038161003816119892101584010038161003816100381610038161003816+100381610038161003816100381610038161198921015840101584010038161003816100381610038161003816) 119889119904
(98)
Now define our complete discrete FVE approximation of(11) by the following find 119880
119899isin 119878
ℎfor 119899 = 1 2 such that
for all Vℎisin 119878
ℎ
(120597119880119899 119868
lowast
ℎVℎ) + 119860 (119905
119899minus12 119880
119899minus12 119868
lowast
ℎVℎ)
+
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12 119880
119896minus12 119868
lowast
ℎVℎ)
= (119891119899minus12
119868lowast
ℎVℎ)
1198800 in 119878
ℎ
(99)
where 119880119899minus12= (119880
119899+ 119880
119899minus1)2
Theorem 19 Let 119906(119905) and 119880119899 be the solutions of problem (2)
and its complete discrete scheme (99) respectively Then forany 119879 gt 0 there exists a positive constant 119862 = 119862(119879) gt 0independent of ℎ such that for 0 lt 119905
119899le 119879
1003817100381710038171003817119906 (119905119899) minus 1198801198991003817100381710038171003817
le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905119899
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
+ 1198621198962(int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905119905
1003817100381710038171003817) 119889119904)
(100)
Proof Let us split the error into two parts 119906(119905119899) minus 119880
119899= 120588
119899+
120579119899 where 120588
119899= 119906(119905
119899)minus119881
ℎ119906(119905
119899) and 120579119899 = 119881
ℎ119906(119905
119899)minus119880
119899 and let119882 = 119881
ℎ119906(119905) isin 119878
ℎbe the Ritz-Volterra projection of 119906 Then
from (2) and (99) we have for all Vℎisin 119878
ℎthe following
(120597120579119899 119868
lowast
ℎVℎ) + 119860 (119905
119899minus12 120579
119899minus12 119868
lowast
ℎVℎ)
+
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12 120579
119896minus12 119868
lowast
ℎVℎ)
= minus (119903119899 119868
lowast
ℎVℎ) forallV
ℎisin 119878
ℎ
(101)
where
119903119899= 119903
1
119899+ 119903
2
119899+ 119903
3
119899+ 119903
4
119899
1199031
119899= 120597120588
119899
1199032
119899= 120597119906 (119905
119899) minus 119906
119905(119905
119899minus12)
1199033
119899= 119860(119905
119899minus12(119906 (119905
119899) + 119906 (119905
119899minus1))
2minus 119906 (119905
119899minus12))
1199034
119899= 119902
119899(119861
ℎ119882)
=
119899
sum
119896=1
120596119899119896119861ℎ(119905
119899minus12 119905
119896minus12119882
119896minus12 119868
lowast
ℎVℎ)
minus int
119905119899minus12
0
119861 (119905119899 119904119882 (119904) 119868
lowast
ℎVℎ) 119889119904
(102)
In fact by Taylor expansion
119906119899+1
= 119906119899+ 119896119906
1015840(119905
119899) + int
119905119899+1
119905119899
11990610158401015840(119904) (119905
119899+1minus 119904) 119889119904
= 119906119899+ 119896119906
1015840(119905
119899) +
1198962
211990610158401015840(119905
119899) +
1198963
6119906(3)
(119905119899)
+1
6int
119905119899+1
119905119899
119906(4)
(119904) (119905119899+1
minus 119904)3
119889119904
(103)
12 Journal of Mathematics
we have100381710038171003817100381710038171199031
119899
10038171003817100381710038171003817=
10038171003817100381710038171003817120597120588
11989910038171003817100381710038171003817le
1
119896int
119905119899
119905119899minus1
10038171003817100381710038171205881199051003817100381710038171003817 119889119904 le 119862
ℎ2
119896int
119905119899
119905119899minus1
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
100381710038171003817100381710038171199032
119899
10038171003817100381710038171003817=
10038171003817100381710038171003817120597119906 (119905
119899) minus 119906
119905(119905
119899minus12)10038171003817100381710038171003817
=1
119896
100381710038171003817100381710038171003817100381710038171003817
int
119905119899
119905119899minus1
(119906119905(119904) minus 119906
119905(119905
119899minus12)) 119889119904
100381710038171003817100381710038171003817100381710038171003817
le 119862119896int
119905119899
119905119899minus1
10038171003817100381710038171003817119906(3)
(119904)10038171003817100381710038171003817119889119904
100381710038171003817100381710038171199033
119899
10038171003817100381710038171003817=
100381710038171003817100381710038171003817100381710038171003817
119860(119905119899minus12
119906 (119905
119899) + 119906 (119905
119899minus1)
2minus 119906 (119905
119899minus12) 119868
lowast
ℎVℎ)
100381710038171003817100381710038171003817100381710038171003817
le 119862119896int
119905119899
119905119899minus1
1003817100381710038171003817119860119906119905119905(119904)
1003817100381710038171003817 119889119904 le 119862119896int
119905119899
119905119899minus1
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
(104)
In addition the quadrature error satisfies100381710038171003817100381710038171199034
119899
10038171003817100381710038171003817= 119902
119899minus12(119861
ℎ119882)
=
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12119882
119896minus12 119868
lowast
ℎVℎ)
minus int
119905119899minus12
0
119861 (119905119899 119904119882 (119904) 119868
lowast
ℎVℎ) 119889119904
le 1198621198962int
119905119899
0
1003817100381710038171003817(119861ℎ119882)
119904119904
1003817100381710038171003817 119889119904
le 1198621198962int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172) 119889119904
119896
119873
sum
119899=1
10038171003817100381710038171199031198991003817100381710038171003817 le 119862ℎ
2int
119905119899
0
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
+ 1198621198962int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172+10038171003817100381710038171003817119906(3)10038171003817100381710038171003817
) 119889119904
(105)
Taking Vℎ= 120579
119899minus12 in (101) and noting that (120597120579119899 119868lowastℎ120579119899minus12
) =
(12)120597|||120579119899|||
2 there is1003816100381610038161003816
1003816100381610038161003816
10038161003816100381610038161205791198991003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816
2
minus10038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus110038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
+ 211989611988810038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus1210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
1
le 1198621198962
119899
sum
119896=1
10038171003817100381710038171003817120579119896minus12100381710038171003817100381710038171
10038171003817100381710038171003817120579119899minus12100381710038171003817100381710038171
+ 1198621198961003817100381710038171003817119903119899
1003817100381710038171003817
10038171003817100381710038171003817120579119899minus1210038171003817100381710038171003817
le11989611988810038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus1210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
1+ 119862119896
2
119899
sum
119896=1
10038171003817100381710038171003817120579119896minus1210038171003817100381710038171003817
2
1+ 119862119896
10038171003817100381710038171199031198991003817100381710038171003817
10038171003817100381710038171003817120579119899minus1210038171003817100381710038171003817
(106)
Summing from 119899 = 1 to 119873 and then after cancelling thecommon factor and using Gronwallrsquos lemma we obtain
10038161003816100381610038161003816
10038161003816100381610038161003816
1003816100381610038161003816100381612057911987310038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
le 11986210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579010038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
+ 119862119896
119873
sum
119896=1
10038171003817100381710038171199031198991003817100381710038171003817 (
1003817100381710038171003817100381712057911989610038171003817100381710038171003817
+10038171003817100381710038171003817120579119896minus1210038171003817100381710038171003817
) (107)
and then
10038161003816100381610038161003816
10038161003816100381610038161003816
1003816100381610038161003816100381612057911987310038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816le 119862
10038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579010038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816+ 119862119896
119873
sum
119899=1
10038171003817100381710038171199031198991003817100381710038171003817
(108)
the theorem follows from the estimates of 120588119899 and 119903119899
References
[1] Z Q Cai ldquoOn the finite volume element methodrdquo NumerischeMathematik vol 58 no 7 pp 713ndash735 1991
[2] S H Chou and D Y Kwak ldquoAnalysis and convergence of aMAC-like scheme for the generalized Stokes problemrdquo Numer-ical Methods for Partial Differential Equations vol 13 no 2 pp147ndash162 1997
[3] P Chatzipantelidis ldquoA finite volume method based on theCrouzeix-Raviart element for elliptic PDErsquos in two dimensionsrdquoNumerische Mathematik vol 82 no 3 pp 409ndash432 1999
[4] P Chatzipantelidis ldquoFinite volumemethods for elliptic PDErsquos anew approachrdquo Mathematical Modelling and Numerical Analy-sis vol 36 no 2 pp 307ndash324 2002
[5] P Chatzipantelidis R D Lazarov and V Thomee ldquoErrorestimates for a finite volume element method for parabolicequations in convex polygonal domainsrdquoNumericalMethods forPartial Differential Equations vol 20 no 5 pp 650ndash674 2004
[6] R E Ewing R D Lazarov and Y Lin ldquoFinite volume elementapproximations of nonlocal in time one-dimensional flows inporous mediardquo Computing vol 64 no 2 pp 157ndash182 2000
[7] R Ewing R Lazarov and Y Lin ldquoFinite volume elementapproximations of nonlocal reactive flows in porous mediardquoNumericalMethods for Partial Differential Equations vol 16 no3 pp 285ndash311 2000
[8] R E Ewing T Lin andY Lin ldquoOn the accuracy of the finite vol-ume element method based on piecewise linear polynomialsrdquoSIAM Journal on Numerical Analysis vol 39 no 6 pp 1865ndash1888 2002
[9] R K Sinha and J Geiser ldquoError estimates for finite volumeelement methods for convection-diffusion-reaction equationsrdquoApplied Numerical Mathematics vol 57 no 1 pp 59ndash72 2007
[10] S H Chou ldquoAnalysis and convergence of a covolume methodfor the generalized Stokes problemrdquo Mathematics of Computa-tion vol 66 no 217 pp 85ndash104 1997
[11] M Berggren ldquoA vertex-centered dual discontinuous Galerkinmethodrdquo Journal of Computational and Applied Mathematicsvol 192 no 1 pp 175ndash181 2006
[12] S H Chou and D Y Kwak ldquoMultigrid algorithms for a vertex-centered covolume method for elliptic problemsrdquo NumerischeMathematik vol 90 no 3 pp 441ndash458 2002
[13] R Eymard T Gallouet and R Herbin Finite Volume MethodsHandbook of Numerical Analysis North-Holland AmsterdamThe Netherlands 2000
[14] V R Voller Basic Control Volume Finite Element Methods forFluids and Solids World Scientific Publishing 2009
[15] J Huang and S Xi ldquoOn the finite volume element method forgeneral self-adjoint elliptic problemsrdquo SIAM Journal on Numer-ical Analysis vol 35 no 5 pp 1762ndash1774 1998
[16] X Ma S Shu and A Zhou ldquoSymmetric finite volume discreti-zations for parabolic problemsrdquo Computer Methods in AppliedMechanics and Engineering vol 192 no 39-40 pp 4467ndash44852003
[17] R D Lazarov and S Z Tomov ldquoAdaptive finite volume elementmethod for convection-diffusion-reaction problems in 3-Drdquo inScientific Computing and Applications vol 7 of Advances inComputation Theory and Practice pp 91ndash106 Nova SciencePublishers Huntington NY USA 2001
[18] I DMishevFinite volume and finite volume elementmethods fornon-symmetric problems [PhD thesis] Texas AampM University1997 Technical Report ISC-96-04-MATH
Journal of Mathematics 13
[19] C Chen and T Shih Finite Element Methods for Integrodifferen-tial Equations World Scientific Publishing Singapore 1998
[20] Y P Lin V Thomee and L B Wahlbin ldquoRitz-Volterra pro-jections to finite-element spaces and applications to integrod-ifferential and related equationsrdquo SIAM Journal on NumericalAnalysis vol 28 no 4 pp 1047ndash1070 1991
[21] VThomeeGalerkin Finite Element Methods for Parabolic Prob-lems Springer Series in Computational Mathematics SpringerNew York NY USA 2006
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Differential EquationsInternational Journal of
Volume 2014
Applied MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical PhysicsAdvances in
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OptimizationJournal of
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CombinatoricsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
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Function Spaces
Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of Mathematics and Mathematical Sciences
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Algebra
Discrete Dynamics in Nature and Society
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Decision SciencesAdvances in
Discrete MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
Volume 2014 Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Stochastic AnalysisInternational Journal of
4 Journal of Mathematics
z
Vz
(a)
z
K
Kz
zK
(b)
Figure 3 119911119870is the barycenter of 119870 and 119902
119890is to be the midpoint of the edge 119890
Kz
zK
z
Figure 4 119902119890is the midpoint of the edge 119890 and 119902
119878119894is the barycenter
of the face 119878119894
Here 119865ℎ(119905) = (119891
1(119905) 119891
2(119905) 119891
119873ℎ(119905))
119879 the mass matrix119872
ℎ= 119872
ℎ119894119895 = (120593
119894 120594
119895) is tridiagonal and both 119860
ℎ(119905) =
119860(119905 120593119894 120594
119895) and 119861
ℎ(119905 119904) = 119861(119905 119904 120593
119894 120594
119895) are positive
definitesIn order to describe features of the bilinear forms defined
in (11) we introduce some discrete norms on 119878ℎin the same
way as in [7]1003817100381710038171003817Vℎ
1003817100381710038171003817
2
0ℎ= (V
ℎ V
ℎ)0ℎ
= (119868lowast
ℎVℎ 119868
lowast
ℎVℎ)
1003816100381610038161003816Vℎ1003816100381610038161003816
2
1ℎ= sum
119909119894isin1198850
ℎ
sum
119909119895isinΠ(119894)
meas (119881119894) (
V119894minus V
119895
119889119894119895
)
2
1003817100381710038171003817Vℎ1003817100381710038171003817
2
1ℎ=1003817100381710038171003817Vℎ
1003817100381710038171003817
2
0ℎ+1003816100381610038161003816Vℎ
1003816100381610038161003816
2
1ℎ
1003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816Vℎ1003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816
2
= (Vℎ 119868
lowast
ℎVℎ)
(15)
where 119889119894119895
= 119889(119909119894 119909
119895) the distance between 119909
119894and 119909
119895
Obviously these norms are well defined for Vℎisin 119878
lowast
ℎas well
and Vℎ0ℎ
= |||Vℎ|||
Hereafter we state the equivalence of discrete norms sdot
0ℎand sdot
1ℎwith usual norms sdot and sdot
1on 119878
ℎ
respectively
Lemma 1 (see [7]) There exist two positive constants 1198620and
1198621such that for all V
ℎisin 119878
ℎ we have
1198620
1003817100381710038171003817Vℎ10038171003817100381710038170ℎ
le1003817100381710038171003817Vℎ
1003817100381710038171003817 le 1198621
1003817100381710038171003817Vℎ10038171003817100381710038170ℎ
forallVℎisin 119878
ℎ
1198620
1003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816Vℎ1003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816 le1003817100381710038171003817Vℎ
1003817100381710038171003817 le 1198621
1003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816Vℎ1003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816 forallVℎisin 119878
ℎ
1198620
1003817100381710038171003817Vℎ10038171003817100381710038171ℎ
le1003817100381710038171003817Vℎ
10038171003817100381710038171le 119862
1
1003817100381710038171003817Vℎ10038171003817100381710038171ℎ
forallVℎisin 119878
ℎ
(16)
Next we recall some properties of the bilinear forms (see[7 18])
Lemma 2 (see [7]) There exist two positive constants 119862 and119862
0such that for all 119906
ℎ V
ℎisin 119878
ℎ we have
119860 (119906ℎ 119868
lowast
ℎVℎ) le 119862
1003817100381710038171003817119906ℎ
10038171003817100381710038171
1003817100381710038171003817Vℎ10038171003817100381710038171 forall119906
ℎ V
ℎisin 119878
ℎ
119860 (Vℎ 119868
lowast
ℎVℎ) ge 119862
0
1003817100381710038171003817Vℎ1003817100381710038171003817
2
1 forallV
ℎisin 119878
ℎ
(17)
The following lemmas are proved in [3 7] which give thekey feature of the bilinear forms in the FVE method
Lemma 3 (see [3]) Assume that 120593 isin 1198821119901
0 Then one has
119860 (119905 120593 Vℎ) minus 119860 (119905 120593 119868
lowast
ℎVℎ)
= sum
119870isin120591ℎ
int120597119870
(119860 (119905) nabla120593 sdot n) (Vℎminus 119868
lowast
ℎVℎ) 119889119904
minus sum
119870isin120591ℎ
int119870
(nabla sdot 119860 (119905) nabla120593) (Vℎminus 119868
lowast
ℎVℎ) 119889119904 forallV
ℎisin 119878
ℎ
(18)
The aforementioned identity holds true when 119860(sdot sdot) is replacedby 119861(119905 119904 sdot sdot)
Lemma 4 (see [3]) Assume that 120593 isin 119878ℎ Then one has
119860 (119905 120593 120594) minus 119860 (119905 120593 119868lowast
ℎ120594) le 119862ℎ
100381610038161003816100381612059310038161003816100381610038161119901
100381610038161003816100381612059410038161003816100381610038161119902
(19)
Furthermore for 120593 isin 1198821119901
0cap119882
2119901 we have
119860 (119905 120593 120594) minus 119860 (119905 120593 119868lowast
ℎ120594) le 119862ℎ
100381710038171003817100381712059310038171003817100381710038172119901
100381710038171003817100381712059410038171003817100381710038171119902
(20)
Journal of Mathematics 5
3 Ritz-Volterra Projection andRelated Estimates
Following [7 19 20] we define the Ritz-Volterra projection119881ℎ(119905) 119867
1
0rarr 119878
ℎas follows
119860 (119905 119906 minus 119881ℎ119906 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 119906 (119904) minus 119881ℎ119906 (119904) 119868
lowast
ℎVℎ) 119889119904 = 0
119905 gt 0 forallVℎisin 119878
ℎ
(21)
This 119881ℎ(119905) is an elliptic projection with memory of 119906
into 119878lowast
ℎ It is easy to see that (21) is actually a system of
integral equations of Volterra type In fact if 119881ℎ(119905)119906 =
sum119873ℎ
119895=1120572119895(119905)120593
119895(119909) then (21) can be rewritten as
119860ℎ(119905) 120572 (119905) + int
119905
0
119861ℎ(119905 119904) 120572 (119904) 119889119904 = 119865
ℎ(119905) (22)
where 119860ℎ(119905) 119861
ℎ(119905 119904) are matrices and 120572(119905) 119865
ℎ(119905) are vectors
defined via
120572 (119905) = (1205721(119905) 120572
2(119905) 120572
119873ℎ(119905))
119879
119865ℎ119896(119905) = 119860 (119905 119906 120594
119896) + int
119905
0
119861 (119905 119904 119906 (119904) 120594119896) 119889119904
119896 = 1 2 119873ℎ
119860ℎ(119905) = 119860 (119905 120593
119896(119909) 120594
119897) 119861
ℎ(119905 119904) = 119861 (119905 119904 120593
119896(119909) 120594
119897)
(23)
From the positivity of 119860 (Lemma 2) and the linearity of(22) we see that the system (22) possesses a unique solution120572(119905) Consequently 119881
ℎ(119905)119906 in (21) is well defined
Set 120588 = 119906 minus 119881ℎ(119905)119906 The following lemma was proved in
[7] which shows the1198671 error estimate for 120588 and its temporalderivative
Lemma 5 (see [7]) Assume that 119863119899
119905119906 isin 119871
infin(119867
1
0cap 119867
2) for all
0 le 119899 le 119896 for some integer 119896 ge 0 Then for 119879 gt 0 fixed thereis a constant 119862 = 119862(119879 119896) gt 0 independent of ℎ and 119906 suchthat for all 0 le 119899 le 119896 and 0 lt 119905 lt 119879
1003817100381710038171003817120588 (119905)10038171003817100381710038171
le 119862ℎ(1199062 + int
119905
0
1199062119889119904)
1003817100381710038171003817119863119899
119905120588 (119905)
10038171003817100381710038171le 119862ℎ(
119899
sum
119894=0
10038171003817100381710038171003817119863
119894
119905119906100381710038171003817100381710038172
+ int
119905
0
1199062119889119904)
(24)
Now we establish 1198712 error estimate for 120588 and its temporalderivative which improves Theorem 22 in [7] This estimateis optimal with respect to the order
Lemma 6 Assume that for some integer 119896 ge 0 119863119899
119905119906 isin
119871infin(119867
1
0cap 119867
2) for all 0 le 119899 le 119896 Then for 119879 gt 0 fixed there is
a constant 119862 = 119862(119879 119896) gt 0 independent of ℎ and 119906 such thatfor all 0 le 119899 le 119896 and 0 lt 119905 lt 119879
1003817100381710038171003817120588 (119905)1003817100381710038171003817 le 119862ℎ
2(1199062 + int
119905
0
1199062119889119904)
1003817100381710038171003817119863119899
119905120588 (119905)
1003817100381710038171003817 le 119862ℎ2(
119899
sum
119894=0
10038171003817100381710038171003817119863
119894
119905119906100381710038171003817100381710038172
+ int
119905
0
1199062119889119904)
(25)
Proof The proof will proceed by duality argument Let 120595 isin
1198672(Ω) cap 119867
1
0(Ω) be the solution of
119860lowast(119905) 120595 = 120588 in Ω
120595 = 0 in 120597Ω
(26)
The solution 120595 isin 1198672(Ω) cap 119867
1
0(Ω) satisfies the following
regularity estimate1003817100381710038171003817120595
10038171003817100381710038172le 119862
10038171003817100381710038171205881003817100381710038171003817 (27)
Multiplying this equation by 120588 and then taking 1198712 innerprod-uct overΩ we obtain the following
10038171003817100381710038171205881003817100381710038171003817
2
= 119860 (119905 120588 120595)
= 119860 (119905 120588 120595 minus 119877ℎ120595) + 119860 (119905 120588 119877
ℎ120595 minus 119868
lowast
ℎ(119877
ℎ120595))
minus int
119905
0
119861 (119905 119904 120588 (119904) 119868lowast
ℎ119877ℎ120595 minus 119877
ℎ120595) 119889119904
minus int
119905
0
119861 (119905 119904 120588 (119904) 119877ℎ120595 minus 120595) 119889119904
minus int
119905
0
119861 (119905 119904 120588 (119904) 120595) 119889119904 = 1198681+ 119868
2+ 119868
3+ 119868
4+ 119868
5
(28)
We have
100381610038161003816100381611986811003816100381610038161003816 +
100381610038161003816100381611986841003816100381610038161003816 le 119862ℎ
2(1199062 + int
119905
0
1199062119889119904)1003817100381710038171003817120595
10038171003817100381710038172 (29)
Applying Lemma 4 we obtain
100381610038161003816100381611986821003816100381610038161003816 +
100381610038161003816100381611986831003816100381610038161003816 le 119862ℎ
2(1199062 + int
119905
0
1199062119889119904)1003817100381710038171003817120595
10038171003817100381710038172 (30)
Finally we have
100381610038161003816100381611986851003816100381610038161003816 le int
119905
0
(120588 (119904) 119861lowast(119905 119904) 120595) 119889119904 le 119862(int
119905
0
10038171003817100381710038171205881003817100381710038171003817 119889119904)
100381710038171003817100381712059510038171003817100381710038172 (31)
then we have
10038171003817100381710038171205881003817100381710038171003817 le 119862ℎ
2(1199062 + int
119905
0
1199062119889119904) + 119862(int
119905
0
10038171003817100381710038171205881003817100381710038171003817 119889119904) (32)
Finally an application of Gronwallrsquos lemma yields the firstestimate
The second inequality follows in a similar fashion
6 Journal of Mathematics
Lemma7 There exists a constant119862 independent of ℎ such that
100381710038171003817100381712058810038171003817100381710038170119901
+ ℎ100381710038171003817100381712058810038171003817100381710038171119901
le 119862ℎ2(1199062119901 + int
119905
0
1199062119901119889119904) (33)
Proof Let 120588119909be an arbitrary component of nabla120588 with 119901 and
119902 conjugate indices we have 120588119909119901
= sup(120588119909 120593) 120593 isin
Cinfin
0(Ω) 120593
119902= 1
For any such 120593 let 120595 be the solution of
119860lowast(119905 120595 V) = minus (120593
119909 V) forallV isin 119867
1
0(Ω)
120595 = 0 on 120597Ω
(34)
It follows from the regularity theory for the elliptic problemthat
100381710038171003817100381712059510038171003817100381710038171119902
le 119862119901
10038171003817100381710038171205931003817100381710038171003817119902
= 119862119901 (35)
We then have by application of (21) that
(120588119909 120593) = 119860 (119905 120588 120595) = 119860 (119905 120588 120595 minus 119877
ℎ120595)
+ 119860 (119905 120588 119877ℎ120595 minus 119868
lowast
ℎ(119877
ℎ120595))
+ int
119905
0
119861 (119905 119904 120588 (119904) 119868lowast
ℎ(119877
ℎ120595)) 119889119904
= 1198681+ 119868
2+ 119868
3
119860 (119905 120588 120595 minus 119877ℎ120595) = 119860 (119905 119877
ℎ119906 minus 119906 120595)
= minus ((119877ℎ119906 minus 119906)
119909 120593) le 119862ℎ1199062119901
(36)
Applying Lemma 4 we have
1198682= 119860 (119905 119906 119877
ℎ120595 minus 119868
lowast
ℎ(119877
ℎ120595)) minus 119860 (119905 119881
ℎ119906 119877
ℎ120595 minus 119868
lowast
ℎ(119877
ℎ120595))
le 119862ℎ1199062119901
(37)
Finally 1198683is estimated as follows
1198683= int
119905
0
119861 (119905 119904 120588 (119904) 119868lowast
ℎ(119877
ℎ120595)) 119889119904 le 119862
119901int
119905
0
100381710038171003817100381712058810038171003817100381710038171119901
119889119904 (38)
Combining these estimates we get
100381710038171003817100381712058810038171003817100381710038171119901
le 119862ℎ1199062119901 + 119862119901int
119905
0
100381710038171003817100381712058810038171003817100381710038171119901
119889119904 (39)
hence by Gronwallrsquos lemma
100381710038171003817100381712058810038171003817100381710038171119901
le 119862ℎ(1199062119901 + int
119905
0
1199062119901119889119904) (40)
The derivation of the error estimate in 119871119901 is similar to the casewhen 119901 = 2
4 Error Estimates forSemidiscrete Approximations
We split the error 119890(119905) = 119906(119905) minus 119906ℎ(119905) as follows
119890 (119905) = (119906 (119905) minus 119881ℎ119906 (119905)) + (119881
ℎ119906 (119905) minus 119906
ℎ(119905)) = 120588 + 120579 (41)
It is easy to see that 120579 = 119881ℎ119906(119905) minus 119906
ℎ(119905) isin 119878
ℎsatisfies an
error equation of the form
(120579119905 119868
lowast
ℎVℎ) + 119860 (119905 120579 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎVℎ) 119889119904
= minus (120588119905 119868
lowast
ℎVℎ) V
ℎisin 119878
ℎ
(42)
Since the estimates of 120588 are already known it is enoughto have estimates for 120579
We will prove a sequence of lemmas which lead to thefollowing result
Lemma8 There is a positive constant119862 independent of ℎ suchthat
|||120579 (119905)||| le 119862(|||120579 (0)|||2+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817 119889119904) (43)
Proof Since 120579 isin 119878ℎwe may take V
ℎ= 120579 in (42) to obtain
1
2
119889
119889119905|||120579 (119905)|||
2+ 119888120579
2
1le
10038171003817100381710038171205881199051003817100381710038171003817 120579 + 119862int
119905
0
12057911198891199041205791
le1003817100381710038171003817120588119905
1003817100381710038171003817 120579 +1
2119888120579
2
1+ 119862int
119905
0
1205792
1119889119904
(44)
and hence by integration and Lemma 1 we have
||120579 (119905)||2+ int
119905
0
1205792
1119889119904
le 119862(|||120579 (0)|||2+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817 120579 119889119904 + int
119905
0
int
119904
0
120579 (120591)2
1119889120591119889119904)
(45)
Gronwallrsquos lemma now implies the following
|||120579 (119905)|||2+ int
119905
0
1205792
1119889119904 le 119862(|||120579 (0)|||
2+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817 120579 119889119904)
le 119862|||120579 (0)|||2+1
2sup119904le119905
120579 (119904)2
+ (int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817 119889119904)
2
(46)
Since this holds for all isin 119869 we may conclude that
||120579 (119905)|| le 119862(|||120579 (0)||| + int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817 119889119904) (47)
Journal of Mathematics 7
Remark 9 If the initial value was chosen so that 1199060ℎminus 119906
0 le
119862ℎ2119906
02 then 120579(0) le 119906
0ℎminus119906
0+119881
ℎ1199060minus119906
0 le 119862ℎ
2119906
02
One can derive
|||120579 (119905)||| le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (48)
Lemma 10 There is a positive constant 119862 independent of ℎsuch that
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
119889119904 + 1205792
1le 119862(120579 (0)
2
1+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
2
119889119904) (49)
Proof Set Vℎ= 120579
119905in (42) to get
10038171003817100381710038171205791199051003817100381710038171003817
2
+1
2
119889
119889119905119860 (119905 120579 119868
lowast
ℎ120579)
= minus (120588119905 119868
lowast
ℎ120579119905) minus int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579119905(119905)) 119889119904
+1
2119860
119905(119905 120579 119868
lowast
ℎ120579)
+1
2[119860 (119905 120579
119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)]
le1
2
10038171003817100381710038171205881199051003817100381710038171003817
2
+1
2
1003816100381610038161003816
1003816100381610038161003816
10038161003816100381610038161205791199051003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816
2
+ 119860119905(119905 120579 119868
lowast
ℎ120579)
+1
2[119860 (119905 120579
119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)]
minus119889
119889119905int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579 (119905)) 119889119904
+ 119861 (119905 119905 120579 (119905) 119868lowast
ℎ120579 (119905)) + int
119905
0
119861119905(119905 119904 120579 (119904) 119868
lowast
ℎ120579 (119905)) 119889119904
(50)
Then
10038171003817100381710038171205791199051003817100381710038171003817
2
+119889
119889119905119860 (119905 120579 119868
lowast
ℎ120579)
le1003817100381710038171003817120588119905
1003817100381710038171003817
2
minus119889
119889119905int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579) 119889119904
+ 119862(1205792
1+ int
119905
0
120579 (119904)2
1119889119904)
+1
2[119860 (119905 120579
119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)]
(51)
In addition recall that
119860 (119905 119906ℎ 119868
lowast
ℎVℎ) minus 119860 (119905 V
ℎ 119868
lowast
ℎ119906ℎ) le 119862ℎ
1003817100381710038171003817119906ℎ
10038171003817100381710038171
1003817100381710038171003817Vℎ10038171003817100381710038171
forall119906ℎ V
ℎisin 119878
ℎ
(52)
then applying an inverse inequality and using kickbackargument we obtain
[119860 (119905 120579119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)] le 119862ℎ
100381710038171003817100381712057911990510038171003817100381710038171
1205791 le 1198621003817100381710038171003817120579119905
1003817100381710038171003817 1205791
le 1205761003817100381710038171003817120579119905
1003817100381710038171003817
2
+ 1198621205792
1
(53)
Combining these estimates we derive
10038171003817100381710038171205791199051003817100381710038171003817
2
+119889
119889119905119860 (119905 120579 119868
lowast
ℎ120579)
le1003817100381710038171003817120588119905
1003817100381710038171003817
2
minus119889
119889119905int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579) 119889119904
+ 119862(1205792
1+ int
119905
0
120579 (119904)2
1119889119904)
(54)
So after integration in time and using the weak coercivity of119860(119905 120579 119868
lowast
ℎ120579) we get
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
119889119904 + 1198880120579
2
1
le 1198880120579 (0)
2
1+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
2
119889119904
+ int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579) 119889119904 + 119862int
119905
0
120579 (119904)2
1119889119904
le 1198880120579 (0)
2
1+119888
2120579
2
1+ 119862(int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
2
+ 120579 (119904)2
1119889119904)
(55)
and by Gronwallrsquos lemma
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
119889119904 + 1198881205792
1le 119862(120579 (0)
2
1+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
2
119889119904) (56)
Remark 11 If 120579(0) = 0 then
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
119889119904 + 1198881205792
1le 119862ℎ
2(int
119905
0
1003817100381710038171003817119906119905
1003817100381710038171003817
2
2119889119904) (57)
Theorem 12 (error estimates in 1198712 and1198671-norms) Let 119906 119906
ℎ
be the solutions of (2) and (11) respectively Assume that 119906 119906119905isin
119871infin(119867
1
0cap 119867
2)
(a) Let 1199060ℎ
be chosen so that 1199060ℎ
minus 1199060 le 119862ℎ
2119906
02
Then for 119879 gt 0 fixed there is a constant 119862 = 119862(119879)
independent of ℎ such that for all 0 lt 119905 lt 119879
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905)
1003817100381710038171003817 le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (58)
(b) Let 1199060ℎ
be chosen so that 1199060ℎminus 119906
01
le 119862ℎ11990602
Then for 119879 gt 0 fixed there is a constant 119862 = 119862(119879)
independent of ℎ such that for all 0 lt 119905 lt 119879
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905))
10038171003817100381710038171le 119862ℎ(
10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (59)
We now prove error estimates for FVE approximations in119871119901 and119882
1119901-norms
8 Journal of Mathematics
Theorem 13 (error estimates in 119871119901 and 119882
1119901-norms) Let119906 119906
ℎbe the solutions of (2) and (11) respectively and 119906
0ℎ=
119881ℎ1199060 Assume that 119906 119906
119905isin 119871
infin(119867
1
0cap 119882
2119901) For ℎ sufficiently
small we have
1003817100381710038171003817119906 minus 119906ℎ
10038171003817100381710038170119901le 119862ℎ
2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
1003817100381710038171003817119906 minus 119906ℎ
10038171003817100381710038171119901le 119862ℎ(
10038171003817100381710038171199060
10038171003817100381710038172+ 1199062119901 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
(60)
Proof If 2 le 119901 lt infin by the following Sobolev embeddinginequality
1205790119901 le 1198621205791 (61)
then the first desired estimate follows from Lemmas 7 and 10Given 120593 isin Cinfin
0(Ω) find 120595 isin 119867
1
0(Ω) such that
119860(119905)lowast120595 = minus120593
119909 in Ω
120595 = 0 on 120597Ω
100381710038171003817100381712059510038171003817100381710038171119902
le100381710038171003817100381712059310038171003817100381710038170119902
(62)
We have
((119906 minus 119906ℎ)119909 120593) = 119860 (119905 119906 minus 119906
ℎ 120595) = 119860 (119905 119906 minus 119906
ℎ 120595 minus 119877
ℎ120595)
+ 119860 (119905 119906 minus 119906ℎ 119877
ℎ120595 minus 119868
lowast
ℎ119877ℎ120595)
minus int
119905
0
119861 (119905 119904 (119906 minus 119906ℎ) (119904) 119868
lowast
ℎ119877ℎ120595) 119889119904
minus ((119906 minus 119906ℎ)119905 119868
lowast
ℎ119877ℎ120595)
= 1198681+ 119868
2+ 119868
3+ 119868
4
100381610038161003816100381611986811003816100381610038161003816 le
1003816100381610038161003816119860 (119905 119906 minus 119877ℎ119906 120595)
1003816100381610038161003816 le 1198621003817100381710038171003817119906 minus 119877
ℎ11990610038171003817100381710038171119901
100381710038171003817100381712059510038171003817100381710038171119902
le 119862ℎ11990621199011003817100381710038171003817120595
10038171003817100381710038171119902
(63)
By Lemma 4
100381610038161003816100381611986821003816100381610038161003816 le 119860 (119905 119906 minus 119906
ℎ 119877
ℎ120595 minus 119868
lowast
ℎ119877ℎ120595)
le 119862ℎ (1003816100381610038161003816119906 minus 119906
ℎ
10038161003816100381610038161119901+ |119906|2119901)
100381710038171003817100381712059510038171003817100381710038171119902
100381610038161003816100381611986831003816100381610038161003816 le int
119905
0
1003817100381710038171003817119906 minus 119906ℎ
100381710038171003817100381711199011198891199041003817100381710038171003817120595
10038171003817100381710038171119902
100381610038161003816100381611986841003816100381610038161003816 le (
1003817100381710038171003817119906 minus 119906ℎ
1003817100381710038171003817)1003817100381710038171003817120595
1003817100381710038171003817 le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
100381710038171003817100381712059510038171003817100381710038171119902
(64)
where we have used the fact 120595 le 1205951119903 119903 gt 1 Combining
these estimates we get
1003816100381610038161003816((119906 minus 119906ℎ)119909 120593)
1003816100381610038161003816 le 119862ℎ(10038171003817100381710038171199060
10038171003817100381710038172+ 1199062119901 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
100381710038171003817100381712059510038171003817100381710038171119902
1003817100381710038171003817(119906 minus 119906ℎ)119909
10038171003817100381710038170119901= sup
((119906 minus 119906ℎ)119909 120593)
100381710038171003817100381712059310038171003817100381710038170119902
le 119862ℎ1003816100381610038161003816119906 minus 119906
ℎ
10038161003816100381610038161119901
+ 119862ℎ(10038171003817100381710038171199060
10038171003817100381710038172+ 1199062119901 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
(65)
Hence using the Poincare inequality we have for ℎ sufficientlysmall
1003817100381710038171003817119906 minus 119906ℎ
10038171003817100381710038171119901le 119862ℎ(
10038171003817100381710038171199060
10038171003817100381710038172+ 1199062119901 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (66)
We compare the relationship between covolume solutionand the Galerkin finite element solution
Corollary 14 Let ℎbe the finite element solution to (2) that
is
(ℎ119905 V
ℎ) + 119860 (119905
ℎ V
ℎ)
+ int
119905
0
119861 (119905 119904 ℎ(119904) V
ℎ) 119889119904 = (119891 V
ℎ) V
ℎisin 119878
ℎ
ℎ(0) = 119877
ℎ1199060
(67)
For ℎ sufficiently small we have
1003817100381710038171003817(ℎminus 119906
ℎ)10038171003817100381710038171119901
le 119862(
ℎ1003817100381710038171003817119906 minus 119906
ℎ
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus 119906
ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817
+int
119905
0
(1003817100381710038171003817(119906 minus 119906
ℎ) (119904)
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus
ℎ) (119904)
10038171003817100381710038171119901) 119889119904
)
le 119862 (119906) ℎ
(68)
Proof By (2) and (67)
((ℎminus 119906)
119905 V
ℎ) + 119860 (119905
ℎminus 119906 V
ℎ)
+ int
119905
0
119861 (119905 119904 (ℎminus 119906) (119904) V
ℎ) 119889119904 = 0 V
ℎisin 119878
ℎ
(69)
Consider the following auxiliary problem For any such 120593 let120595 be the solution of the following
119860(119905)lowast120595 = minus120593
119909 in Ω
120595 = 0 on 120597Ω
(70)
Journal of Mathematics 9
with1003817100381710038171003817120595
10038171003817100381710038171119902le100381710038171003817100381712059310038171003817100381710038170119902
((ℎminus 119906
ℎ)119909 120593)
= 119860 (119905 ℎminus 119906
ℎ 120595)
= 119860 (119905 ℎminus 119906
ℎ 120595 minus 119877
ℎ120595) + 119860 (119905 119906 minus 119906
ℎ 119877
ℎ120595)
minus 119860 (119905 119906 minus 119906ℎ 119868
lowast
ℎ119877ℎ120595) minus ((119906 minus 119906
ℎ)119905 119868
lowast
ℎ119877ℎ120595)
minus int
119905
0
119861 (119905 119904 (119906 minus 119906ℎ) (119904) 119868
lowast
ℎ119877ℎ120595) 119889119904
+ 119860 (119905 ℎminus 119906 119877
ℎ120595)
= [119860 (119905 119906 minus 119906ℎ 119877
ℎ120595) minus 119860 (119905 119906 minus 119906
ℎ 119868
lowast
ℎ119877ℎ120595)]
minus ((119906 minus 119906ℎ)119905 119868
lowast
ℎ119877ℎ120595) minus ((
ℎminus 119906)
119905 119877
ℎ120595)
minus int
119905
0
119861 (119905 119904 (119906 minus 119906ℎ) (119904) 119868
lowast
ℎ119877ℎ120595) 119889119904
minus int
119905
0
119861 (119905 119904 (ℎminus 119906) (119904) 119877
ℎ120595) 119889119904
= 1198681+ 119868
2+ 119868
3
(71)
On the other hand10038161003816100381610038161198681
1003816100381610038161003816 le 119862ℎ1003817100381710038171003817119906 minus 119906
ℎ
10038171003817100381710038171119901
100381710038171003817100381712059510038171003817100381710038171119902
100381610038161003816100381611986821003816100381610038161003816 le 119862 (
1003817100381710038171003817(119906 minus 119906ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817)1003817100381710038171003817120595
1003817100381710038171003817
le 119862 (1003817100381710038171003817(119906 minus 119906
ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817)1003817100381710038171003817120595
10038171003817100381710038171119902
(72)
where we have used the fact 120595 le 1205951119903 119903 gt 1
100381610038161003816100381611986831003816100381610038161003816 le int
119905
0
(1003817100381710038171003817(119906 minus 119906
ℎ) (119904)
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus
ℎ) (119904)
10038171003817100381710038171119901) 119889119904
100381710038171003817100381712059510038171003817100381710038171119902
1003817100381710038171003817(ℎminus 119906
ℎ)119909
10038171003817100381710038170119901
= sup120593isinCinfin0
((ℎminus 119906
ℎ)119909 120593)
100381710038171003817100381712059310038171003817100381710038170119902
le 119862(
ℎ1003817100381710038171003817119906 minus 119906
ℎ
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus 119906
ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817
+int
119905
0
(1003817100381710038171003817(119906 minus 119906
ℎ) (119904)
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus
ℎ) (119904)
10038171003817100381710038171119901) 119889119904
)
(73)
We deduce the result from the known finite element esti-mates
Remark 15 In order to estimate (119906 minus 119906ℎ)119905 by differentiating
(42) with respect to 119905 we obtain
(120579119905119905 119868
lowast
ℎVℎ) + 119860 (119905 120579
119905 119868
lowast
ℎVℎ) + 119860
119905(119905 120579
119905 119868
lowast
ℎVℎ)
+ 119861 (119905 119905 120579 119868lowast
ℎVℎ) + int
119905
0
119861119905(119905 119904 120579 (119904) 119868
lowast
ℎVℎ) 119889119904
= minus (120588119905119905 119868
lowast
ℎVℎ)
(74)
Setting Vℎ= 120579
119905 we obtain
1
2
119889
119889119905
1003816100381610038161003816
1003816100381610038161003816
10038161003816100381610038161205791199051003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816
2
+ 1198881003817100381710038171003817120579119905
1003817100381710038171003817
2
1le1003817100381710038171003817120588119905119905
1003817100381710038171003817
10038171003817100381710038171205791199051003817100381710038171003817
+1
21198881003817100381710038171003817120579119905
1003817100381710038171003817
2
1+ 119862120579
2
1+ int
119905
0
1205792
1119889119904
le1003817100381710038171003817120588119905119905
1003817100381710038171003817
10038171003817100381710038171205791199051003817100381710038171003817 +
1
21198881003817100381710038171003817120579119905
1003817100381710038171003817
2
1+ 119862int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
1119889119904
(75)
Using kickback argument integrating and applying Gron-wallrsquos lemma we deduce
10038171003817100381710038171205791199051003817100381710038171003817 le 119862(
1003817100381710038171003817120579119905 (0)1003817100381710038171003817 + int
119905
0
100381710038171003817100381712058811990511990510038171003817100381710038171119889119904)
le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+10038171003817100381710038171199061
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904)
(76)
5 The Lumped Mass Finite VolumeElement Method
In this section we restrict our study to the 2D case A simpleway to define the lumped mass scheme [21] is to replace themass matrix 119872
ℎin (14) by the diagonal matrix 119872
ℎobtained
by taking for its diagonal elements the numbers 119872ℎ119894119894
=
sum119873ℎ
119895=1119872
ℎ119894119895or by lumping all masses in one row into the
diagonal entryThismakes the inversion of thematrix in frontof1205721015840
(119905) a trivialityWewill therefore study thematrix problem
119872ℎ1205721015840(119905) + 119860
ℎ(119905) 120572 (119905) + int
119905
0
119861ℎ(119905 119904) 120572 (119904) 119889119904 = 119865
ℎ(119905) (77)
We know that the lumped mass method defined by (77)above is equivalent to
(119868lowast
ℎ119906ℎ119905 119868
lowast
ℎVℎ) + 119860 (119905 119906
ℎ 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 119906ℎ(119904) 119868
lowast
ℎVℎ) 119889119904
= (119891 119868lowast
ℎVℎ) V
ℎisin 119878
ℎ
(78)
Our alternative interpretation of this procedure will beto think of (77) as being obtained by evaluating the firstterm in (78) by numerical quadrature Let 119870 be a triangle ofthe triangulation 119879
ℎ let 119909
119895 119895 = 1 2 3 be its vertices and
consider the quadrature formula
119876119870ℎ
(119891) =1
3area119870
3
sum
119895=1
119891 (119909119895) ≃ int
119870
119891119889119909 (79)
We may then define the associated bilinear form in 119878ℎtimes
119878lowast
ℎ using the quadrature scheme by the following
(Vℎ 120578
ℎ)ℎ= sum
119870isin119879ℎ
119876119870ℎ
(Vℎ120578ℎ) = sum
119909119894isin119873119886
ℎ
Vℎ(119909
119894) 120578
ℎ(119909
119894)10038161003816100381610038161003816119881119909119894
10038161003816100381610038161003816
forallVℎisin 119878
ℎ 120578
ℎisin 119878
lowast
ℎ
(80)
10 Journal of Mathematics
We note that Vℎ2
ℎ= (V
ℎ 119868
lowast
ℎVℎ)ℎis a norm in 119878
ℎwhich is
equivalent to the 1198712-norm uniformly in ℎ that is there existtwo positive constants 119862
1and 119862
2such that for all V
ℎisin 119878
ℎ we
have
1198620
1003817100381710038171003817Vℎ1003817100381710038171003817 le
1003817100381710038171003817Vℎ1003817100381710038171003817ℎ
le 1198621
1003817100381710038171003817Vℎ1003817100381710038171003817 forallV
ℎisin 119878
ℎ (81)
We note that the aforementioned definition (Vℎ 120578
ℎ)ℎmay
be used also for 120578ℎisin 119878
ℎand that (V
ℎ 119908
ℎ)ℎ= (V
ℎ 119868
lowast
ℎ119908
ℎ)ℎfor
Vℎ 119908
ℎisin 119878
ℎ
The lumpedmass method defined by (78) is equivalent to
(119906ℎ119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 119906
ℎ 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 119906ℎ(119904) 119868
lowast
ℎVℎ) 119889119904
= (119891 119868lowast
ℎVℎ) V
ℎisin 119878
ℎ
(82)
We introduce the quadrature error
120576ℎ(V
ℎ 119908
ℎ) = (V
ℎ 119908
ℎ)ℎminus (V
ℎ 119908
ℎ) (83)
Lemma 16 (see [21]) Let Vℎ 119908
ℎisin 119878
ℎ Then
1003816100381610038161003816120576ℎ (Vℎ 119908ℎ)1003816100381610038161003816 le 119862ℎ
2 1003817100381710038171003817nablaVℎ1003817100381710038171003817
1003817100381710038171003817nabla119908ℎ
1003817100381710038171003817 (84)
Theorem 17 Let 119906ℎand 119906 be the solutions of (82) and (2)
respectively and assume 119906ℎ(0) = 119877
ℎ1199060 Then we have for the
error in the lumped mass semidiscrete method for 119905 ge 0 thefollowing
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905)
1003817100381710038171003817 le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ 1199062 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (85)
Proof In order to estimate 120579 we write
(120579119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 120579 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎVℎ) 119889119904
= (119906ℎ119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 119906
ℎ 119868
lowast
ℎVℎ)
+ int
119905
0
119861 (119905 119904 119906ℎ(119904) 119868
lowast
ℎVℎ) 119889119904
minus ((119881ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus 119860 (119905 119881
ℎ119906 119868
lowast
ℎVℎ)
minus int
119905
0
119861 (119905 119904 119881ℎ119906 (119904) 119868
lowast
ℎVℎ) 119889119904
= (119891 119868lowast
ℎVℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus 119860 (119905 119906 119868
lowast
ℎVℎ)
minus int
119905
0
119861 (119905 119904 119906 (119904) 119868lowast
ℎVℎ)
= (119906119905 119868
lowast
ℎVℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)ℎ
= minus (120588119905 119868
lowast
ℎVℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)ℎ+ ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
(86)
We rewrite
((119881ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
= ((119881ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus ((119881
ℎ119906)
119905 V
ℎ)
+ ((119881ℎ119906)
119905 V
ℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
= 120576ℎ((119881
ℎ119906)
119905 V
ℎ) + ((119881
ℎ119906)
119905 V
ℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
(120579119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 120579 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎVℎ) 119889119904
= minus (120588119905 119868
lowast
ℎVℎ) + 120576
ℎ((119881
ℎ119906)
119905 V
ℎ)
+ ((119881ℎ119906)
119905 V
ℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
(87)
Setting Vℎ= 120579 in (87) we obtain
1
2
119889
119889119905120579
2
ℎ+ 119888
01205792
1
le1003817100381710038171003817120588119905
1003817100381710038171003817 120579 +1
21198880120579
2
1+ 119862int
119905
0
1205792
1119889119904
+ 120576ℎ((119881
ℎ119906)
119905 120579) + ((119881
ℎ119906)
119905 120579) minus ((119881
ℎ119906)
119905 119868
lowast
ℎ120579)
(88)
Using Lemma 16 and the inverse estimate we get1003816100381610038161003816120576ℎ (119881ℎ
119906119905 120579)
1003816100381610038161003816 le 119862ℎ2 1003817100381710038171003817nabla(119881ℎ
119906)119905
1003817100381710038171003817 nabla120579
le 119862ℎ2 1003817100381710038171003817nabla119906119905
1003817100381710038171003817 nabla120579
le 119862ℎ1003817100381710038171003817nabla119906119905
1003817100381710038171003817 120579
(89)
we have1003816100381610038161003816((119881ℎ
119906)119905 120579) minus ((119881
ℎ119906)
119905 119868
lowast
ℎ120579)1003816100381610038161003816 le 119862ℎ
1003817100381710038171003817nabla119906119905
1003817100381710038171003817 120579 (90)
Using Youngrsquos inequality and Gronwallrsquos lemma to eliminate120579
1on the right-hand side and using integration in 119905 we get
the result
1
2
119889
119889119905120579
2
ℎ+ 119888
0 120579 le1003817100381710038171003817120588119905
1003817100381710038171003817 120579 + 119862ℎ1003817100381710038171003817nabla119906119905
1003817100381710038171003817 120579 (91)
Using Youngrsquos inequality to eliminate 120579 on the right handside it becomes
Using integration in 119905 we get the result
We will now show that the 1198671-norm error bound of
theorem remains valid for the lumped mass method (82)
Theorem 18 Let 119906ℎand 119906 be the solutions of (82) and (2)
respectively and assume
119906ℎ(0) = 119877
ℎ1199060
10038171003817100381710038171199061ℎ(0) minus 119906
1
1003817100381710038171003817 le 119862ℎ210038171003817100381710038171199061
10038171003817100381710038172 (92)
Then we have for the error in the lumped mass semidiscretemethod for 119905 ge 0 the following
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905)
10038171003817100381710038171le 119862ℎ
2(10038171003817100381710038171199060
10038171003817100381710038172+10038171003817100381710038171199061
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904)
(93)
Journal of Mathematics 11
Proof Setting Vℎ= 120579
119905in (87) we obtain
10038171003817100381710038171205791199051003817100381710038171003817
2
ℎ+1
2
119889
119889119905119860 (119905 120579 119868
lowast
ℎ120579)
=1
2119860
119905(119905 120579 119868
lowast
ℎ120579) +
1
2[119860 (119905 120579
119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)]
119861 (119905 119905 120579 (119905) 119868lowast
ℎ120579 (119905)) + int
119905
0
119861119905(119905 119904 120579 (119904) 119868
lowast
ℎ120579 (119905)) 119889119904
minus119889
119889119905int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579 (119905)) 119889119904 minus (120588
119905 119868
lowast
ℎ120579119905)
minus 120576ℎ((119881
ℎ119906)
119905 120579
119905) + ((119881
ℎ119906)
119905 120579) minus ((119881
ℎ119906)
119905 119868
lowast
ℎ120579)
(94)
It follows thus that using integration in 119905 and Gronwallrsquoslemma we have
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
ℎ+ 120579
2
1le 119862nabla120579 (0)
2+ 119862int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
10038171003817100381710038171205791199051003817100381710038171003817 119889119904
+ 119862ℎ2int
119905
0
1003817100381710038171003817119906119905
1003817100381710038171003817
2
1119889119904
(95)
6 Full Discretization
Let 120597119880119899= (119880
119899minus119880
119899minus1)119896 be the backward difference quotient
of 119880119899 assume that 119860ℎ
= 119875ℎ119860 is a discrete analogue of 119860
(similarly 119861ℎ
= 119875ℎ119861) where 119875
ℎ 119871
2(Ω) rarr 119878
lowast
ℎthe 119871
2
projection is defined by
(119875ℎV 119868lowast
ℎVℎ) = (V 119868lowast
ℎVℎ) V isin 119871
2(Ω) V
ℎisin 119878
ℎ (96)
In order to define fully discrete approximation of (11) wediscretize the time by taking 119905
119899= 119899119896 119896 gt 0 119899 = 1 2 and
use the numerical quadrature
int
119905119899minus12
0
119892 (119904) 119889119904 asymp
119899
sum
119896=1
120596119899119896119892 (119905
119896minus12) 119905
119899minus12= (119899 minus
1
2) 119896
(97)
Here 120596119899119896 are the integrationweights andwe assume that
the following error estimate is valid
119902119899(119892) = int
119905119899minus12
0
119892 (119904) 119889119904minus
119899
sum
119896=1
120596119899119896119892 (119905
119896minus12)
le 1198621198962int
119905119899
0
(10038161003816100381610038161003816119892101584010038161003816100381610038161003816+100381610038161003816100381610038161198921015840101584010038161003816100381610038161003816) 119889119904
(98)
Now define our complete discrete FVE approximation of(11) by the following find 119880
119899isin 119878
ℎfor 119899 = 1 2 such that
for all Vℎisin 119878
ℎ
(120597119880119899 119868
lowast
ℎVℎ) + 119860 (119905
119899minus12 119880
119899minus12 119868
lowast
ℎVℎ)
+
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12 119880
119896minus12 119868
lowast
ℎVℎ)
= (119891119899minus12
119868lowast
ℎVℎ)
1198800 in 119878
ℎ
(99)
where 119880119899minus12= (119880
119899+ 119880
119899minus1)2
Theorem 19 Let 119906(119905) and 119880119899 be the solutions of problem (2)
and its complete discrete scheme (99) respectively Then forany 119879 gt 0 there exists a positive constant 119862 = 119862(119879) gt 0independent of ℎ such that for 0 lt 119905
119899le 119879
1003817100381710038171003817119906 (119905119899) minus 1198801198991003817100381710038171003817
le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905119899
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
+ 1198621198962(int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905119905
1003817100381710038171003817) 119889119904)
(100)
Proof Let us split the error into two parts 119906(119905119899) minus 119880
119899= 120588
119899+
120579119899 where 120588
119899= 119906(119905
119899)minus119881
ℎ119906(119905
119899) and 120579119899 = 119881
ℎ119906(119905
119899)minus119880
119899 and let119882 = 119881
ℎ119906(119905) isin 119878
ℎbe the Ritz-Volterra projection of 119906 Then
from (2) and (99) we have for all Vℎisin 119878
ℎthe following
(120597120579119899 119868
lowast
ℎVℎ) + 119860 (119905
119899minus12 120579
119899minus12 119868
lowast
ℎVℎ)
+
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12 120579
119896minus12 119868
lowast
ℎVℎ)
= minus (119903119899 119868
lowast
ℎVℎ) forallV
ℎisin 119878
ℎ
(101)
where
119903119899= 119903
1
119899+ 119903
2
119899+ 119903
3
119899+ 119903
4
119899
1199031
119899= 120597120588
119899
1199032
119899= 120597119906 (119905
119899) minus 119906
119905(119905
119899minus12)
1199033
119899= 119860(119905
119899minus12(119906 (119905
119899) + 119906 (119905
119899minus1))
2minus 119906 (119905
119899minus12))
1199034
119899= 119902
119899(119861
ℎ119882)
=
119899
sum
119896=1
120596119899119896119861ℎ(119905
119899minus12 119905
119896minus12119882
119896minus12 119868
lowast
ℎVℎ)
minus int
119905119899minus12
0
119861 (119905119899 119904119882 (119904) 119868
lowast
ℎVℎ) 119889119904
(102)
In fact by Taylor expansion
119906119899+1
= 119906119899+ 119896119906
1015840(119905
119899) + int
119905119899+1
119905119899
11990610158401015840(119904) (119905
119899+1minus 119904) 119889119904
= 119906119899+ 119896119906
1015840(119905
119899) +
1198962
211990610158401015840(119905
119899) +
1198963
6119906(3)
(119905119899)
+1
6int
119905119899+1
119905119899
119906(4)
(119904) (119905119899+1
minus 119904)3
119889119904
(103)
12 Journal of Mathematics
we have100381710038171003817100381710038171199031
119899
10038171003817100381710038171003817=
10038171003817100381710038171003817120597120588
11989910038171003817100381710038171003817le
1
119896int
119905119899
119905119899minus1
10038171003817100381710038171205881199051003817100381710038171003817 119889119904 le 119862
ℎ2
119896int
119905119899
119905119899minus1
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
100381710038171003817100381710038171199032
119899
10038171003817100381710038171003817=
10038171003817100381710038171003817120597119906 (119905
119899) minus 119906
119905(119905
119899minus12)10038171003817100381710038171003817
=1
119896
100381710038171003817100381710038171003817100381710038171003817
int
119905119899
119905119899minus1
(119906119905(119904) minus 119906
119905(119905
119899minus12)) 119889119904
100381710038171003817100381710038171003817100381710038171003817
le 119862119896int
119905119899
119905119899minus1
10038171003817100381710038171003817119906(3)
(119904)10038171003817100381710038171003817119889119904
100381710038171003817100381710038171199033
119899
10038171003817100381710038171003817=
100381710038171003817100381710038171003817100381710038171003817
119860(119905119899minus12
119906 (119905
119899) + 119906 (119905
119899minus1)
2minus 119906 (119905
119899minus12) 119868
lowast
ℎVℎ)
100381710038171003817100381710038171003817100381710038171003817
le 119862119896int
119905119899
119905119899minus1
1003817100381710038171003817119860119906119905119905(119904)
1003817100381710038171003817 119889119904 le 119862119896int
119905119899
119905119899minus1
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
(104)
In addition the quadrature error satisfies100381710038171003817100381710038171199034
119899
10038171003817100381710038171003817= 119902
119899minus12(119861
ℎ119882)
=
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12119882
119896minus12 119868
lowast
ℎVℎ)
minus int
119905119899minus12
0
119861 (119905119899 119904119882 (119904) 119868
lowast
ℎVℎ) 119889119904
le 1198621198962int
119905119899
0
1003817100381710038171003817(119861ℎ119882)
119904119904
1003817100381710038171003817 119889119904
le 1198621198962int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172) 119889119904
119896
119873
sum
119899=1
10038171003817100381710038171199031198991003817100381710038171003817 le 119862ℎ
2int
119905119899
0
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
+ 1198621198962int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172+10038171003817100381710038171003817119906(3)10038171003817100381710038171003817
) 119889119904
(105)
Taking Vℎ= 120579
119899minus12 in (101) and noting that (120597120579119899 119868lowastℎ120579119899minus12
) =
(12)120597|||120579119899|||
2 there is1003816100381610038161003816
1003816100381610038161003816
10038161003816100381610038161205791198991003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816
2
minus10038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus110038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
+ 211989611988810038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus1210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
1
le 1198621198962
119899
sum
119896=1
10038171003817100381710038171003817120579119896minus12100381710038171003817100381710038171
10038171003817100381710038171003817120579119899minus12100381710038171003817100381710038171
+ 1198621198961003817100381710038171003817119903119899
1003817100381710038171003817
10038171003817100381710038171003817120579119899minus1210038171003817100381710038171003817
le11989611988810038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus1210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
1+ 119862119896
2
119899
sum
119896=1
10038171003817100381710038171003817120579119896minus1210038171003817100381710038171003817
2
1+ 119862119896
10038171003817100381710038171199031198991003817100381710038171003817
10038171003817100381710038171003817120579119899minus1210038171003817100381710038171003817
(106)
Summing from 119899 = 1 to 119873 and then after cancelling thecommon factor and using Gronwallrsquos lemma we obtain
10038161003816100381610038161003816
10038161003816100381610038161003816
1003816100381610038161003816100381612057911987310038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
le 11986210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579010038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
+ 119862119896
119873
sum
119896=1
10038171003817100381710038171199031198991003817100381710038171003817 (
1003817100381710038171003817100381712057911989610038171003817100381710038171003817
+10038171003817100381710038171003817120579119896minus1210038171003817100381710038171003817
) (107)
and then
10038161003816100381610038161003816
10038161003816100381610038161003816
1003816100381610038161003816100381612057911987310038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816le 119862
10038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579010038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816+ 119862119896
119873
sum
119899=1
10038171003817100381710038171199031198991003817100381710038171003817
(108)
the theorem follows from the estimates of 120588119899 and 119903119899
References
[1] Z Q Cai ldquoOn the finite volume element methodrdquo NumerischeMathematik vol 58 no 7 pp 713ndash735 1991
[2] S H Chou and D Y Kwak ldquoAnalysis and convergence of aMAC-like scheme for the generalized Stokes problemrdquo Numer-ical Methods for Partial Differential Equations vol 13 no 2 pp147ndash162 1997
[3] P Chatzipantelidis ldquoA finite volume method based on theCrouzeix-Raviart element for elliptic PDErsquos in two dimensionsrdquoNumerische Mathematik vol 82 no 3 pp 409ndash432 1999
[4] P Chatzipantelidis ldquoFinite volumemethods for elliptic PDErsquos anew approachrdquo Mathematical Modelling and Numerical Analy-sis vol 36 no 2 pp 307ndash324 2002
[5] P Chatzipantelidis R D Lazarov and V Thomee ldquoErrorestimates for a finite volume element method for parabolicequations in convex polygonal domainsrdquoNumericalMethods forPartial Differential Equations vol 20 no 5 pp 650ndash674 2004
[6] R E Ewing R D Lazarov and Y Lin ldquoFinite volume elementapproximations of nonlocal in time one-dimensional flows inporous mediardquo Computing vol 64 no 2 pp 157ndash182 2000
[7] R Ewing R Lazarov and Y Lin ldquoFinite volume elementapproximations of nonlocal reactive flows in porous mediardquoNumericalMethods for Partial Differential Equations vol 16 no3 pp 285ndash311 2000
[8] R E Ewing T Lin andY Lin ldquoOn the accuracy of the finite vol-ume element method based on piecewise linear polynomialsrdquoSIAM Journal on Numerical Analysis vol 39 no 6 pp 1865ndash1888 2002
[9] R K Sinha and J Geiser ldquoError estimates for finite volumeelement methods for convection-diffusion-reaction equationsrdquoApplied Numerical Mathematics vol 57 no 1 pp 59ndash72 2007
[10] S H Chou ldquoAnalysis and convergence of a covolume methodfor the generalized Stokes problemrdquo Mathematics of Computa-tion vol 66 no 217 pp 85ndash104 1997
[11] M Berggren ldquoA vertex-centered dual discontinuous Galerkinmethodrdquo Journal of Computational and Applied Mathematicsvol 192 no 1 pp 175ndash181 2006
[12] S H Chou and D Y Kwak ldquoMultigrid algorithms for a vertex-centered covolume method for elliptic problemsrdquo NumerischeMathematik vol 90 no 3 pp 441ndash458 2002
[13] R Eymard T Gallouet and R Herbin Finite Volume MethodsHandbook of Numerical Analysis North-Holland AmsterdamThe Netherlands 2000
[14] V R Voller Basic Control Volume Finite Element Methods forFluids and Solids World Scientific Publishing 2009
[15] J Huang and S Xi ldquoOn the finite volume element method forgeneral self-adjoint elliptic problemsrdquo SIAM Journal on Numer-ical Analysis vol 35 no 5 pp 1762ndash1774 1998
[16] X Ma S Shu and A Zhou ldquoSymmetric finite volume discreti-zations for parabolic problemsrdquo Computer Methods in AppliedMechanics and Engineering vol 192 no 39-40 pp 4467ndash44852003
[17] R D Lazarov and S Z Tomov ldquoAdaptive finite volume elementmethod for convection-diffusion-reaction problems in 3-Drdquo inScientific Computing and Applications vol 7 of Advances inComputation Theory and Practice pp 91ndash106 Nova SciencePublishers Huntington NY USA 2001
[18] I DMishevFinite volume and finite volume elementmethods fornon-symmetric problems [PhD thesis] Texas AampM University1997 Technical Report ISC-96-04-MATH
Journal of Mathematics 13
[19] C Chen and T Shih Finite Element Methods for Integrodifferen-tial Equations World Scientific Publishing Singapore 1998
[20] Y P Lin V Thomee and L B Wahlbin ldquoRitz-Volterra pro-jections to finite-element spaces and applications to integrod-ifferential and related equationsrdquo SIAM Journal on NumericalAnalysis vol 28 no 4 pp 1047ndash1070 1991
[21] VThomeeGalerkin Finite Element Methods for Parabolic Prob-lems Springer Series in Computational Mathematics SpringerNew York NY USA 2006
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Differential EquationsInternational Journal of
Volume 2014
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International Journal of
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Function Spaces
Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Algebra
Discrete Dynamics in Nature and Society
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Decision SciencesAdvances in
Discrete MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
Volume 2014 Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Stochastic AnalysisInternational Journal of
Journal of Mathematics 5
3 Ritz-Volterra Projection andRelated Estimates
Following [7 19 20] we define the Ritz-Volterra projection119881ℎ(119905) 119867
1
0rarr 119878
ℎas follows
119860 (119905 119906 minus 119881ℎ119906 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 119906 (119904) minus 119881ℎ119906 (119904) 119868
lowast
ℎVℎ) 119889119904 = 0
119905 gt 0 forallVℎisin 119878
ℎ
(21)
This 119881ℎ(119905) is an elliptic projection with memory of 119906
into 119878lowast
ℎ It is easy to see that (21) is actually a system of
integral equations of Volterra type In fact if 119881ℎ(119905)119906 =
sum119873ℎ
119895=1120572119895(119905)120593
119895(119909) then (21) can be rewritten as
119860ℎ(119905) 120572 (119905) + int
119905
0
119861ℎ(119905 119904) 120572 (119904) 119889119904 = 119865
ℎ(119905) (22)
where 119860ℎ(119905) 119861
ℎ(119905 119904) are matrices and 120572(119905) 119865
ℎ(119905) are vectors
defined via
120572 (119905) = (1205721(119905) 120572
2(119905) 120572
119873ℎ(119905))
119879
119865ℎ119896(119905) = 119860 (119905 119906 120594
119896) + int
119905
0
119861 (119905 119904 119906 (119904) 120594119896) 119889119904
119896 = 1 2 119873ℎ
119860ℎ(119905) = 119860 (119905 120593
119896(119909) 120594
119897) 119861
ℎ(119905 119904) = 119861 (119905 119904 120593
119896(119909) 120594
119897)
(23)
From the positivity of 119860 (Lemma 2) and the linearity of(22) we see that the system (22) possesses a unique solution120572(119905) Consequently 119881
ℎ(119905)119906 in (21) is well defined
Set 120588 = 119906 minus 119881ℎ(119905)119906 The following lemma was proved in
[7] which shows the1198671 error estimate for 120588 and its temporalderivative
Lemma 5 (see [7]) Assume that 119863119899
119905119906 isin 119871
infin(119867
1
0cap 119867
2) for all
0 le 119899 le 119896 for some integer 119896 ge 0 Then for 119879 gt 0 fixed thereis a constant 119862 = 119862(119879 119896) gt 0 independent of ℎ and 119906 suchthat for all 0 le 119899 le 119896 and 0 lt 119905 lt 119879
1003817100381710038171003817120588 (119905)10038171003817100381710038171
le 119862ℎ(1199062 + int
119905
0
1199062119889119904)
1003817100381710038171003817119863119899
119905120588 (119905)
10038171003817100381710038171le 119862ℎ(
119899
sum
119894=0
10038171003817100381710038171003817119863
119894
119905119906100381710038171003817100381710038172
+ int
119905
0
1199062119889119904)
(24)
Now we establish 1198712 error estimate for 120588 and its temporalderivative which improves Theorem 22 in [7] This estimateis optimal with respect to the order
Lemma 6 Assume that for some integer 119896 ge 0 119863119899
119905119906 isin
119871infin(119867
1
0cap 119867
2) for all 0 le 119899 le 119896 Then for 119879 gt 0 fixed there is
a constant 119862 = 119862(119879 119896) gt 0 independent of ℎ and 119906 such thatfor all 0 le 119899 le 119896 and 0 lt 119905 lt 119879
1003817100381710038171003817120588 (119905)1003817100381710038171003817 le 119862ℎ
2(1199062 + int
119905
0
1199062119889119904)
1003817100381710038171003817119863119899
119905120588 (119905)
1003817100381710038171003817 le 119862ℎ2(
119899
sum
119894=0
10038171003817100381710038171003817119863
119894
119905119906100381710038171003817100381710038172
+ int
119905
0
1199062119889119904)
(25)
Proof The proof will proceed by duality argument Let 120595 isin
1198672(Ω) cap 119867
1
0(Ω) be the solution of
119860lowast(119905) 120595 = 120588 in Ω
120595 = 0 in 120597Ω
(26)
The solution 120595 isin 1198672(Ω) cap 119867
1
0(Ω) satisfies the following
regularity estimate1003817100381710038171003817120595
10038171003817100381710038172le 119862
10038171003817100381710038171205881003817100381710038171003817 (27)
Multiplying this equation by 120588 and then taking 1198712 innerprod-uct overΩ we obtain the following
10038171003817100381710038171205881003817100381710038171003817
2
= 119860 (119905 120588 120595)
= 119860 (119905 120588 120595 minus 119877ℎ120595) + 119860 (119905 120588 119877
ℎ120595 minus 119868
lowast
ℎ(119877
ℎ120595))
minus int
119905
0
119861 (119905 119904 120588 (119904) 119868lowast
ℎ119877ℎ120595 minus 119877
ℎ120595) 119889119904
minus int
119905
0
119861 (119905 119904 120588 (119904) 119877ℎ120595 minus 120595) 119889119904
minus int
119905
0
119861 (119905 119904 120588 (119904) 120595) 119889119904 = 1198681+ 119868
2+ 119868
3+ 119868
4+ 119868
5
(28)
We have
100381610038161003816100381611986811003816100381610038161003816 +
100381610038161003816100381611986841003816100381610038161003816 le 119862ℎ
2(1199062 + int
119905
0
1199062119889119904)1003817100381710038171003817120595
10038171003817100381710038172 (29)
Applying Lemma 4 we obtain
100381610038161003816100381611986821003816100381610038161003816 +
100381610038161003816100381611986831003816100381610038161003816 le 119862ℎ
2(1199062 + int
119905
0
1199062119889119904)1003817100381710038171003817120595
10038171003817100381710038172 (30)
Finally we have
100381610038161003816100381611986851003816100381610038161003816 le int
119905
0
(120588 (119904) 119861lowast(119905 119904) 120595) 119889119904 le 119862(int
119905
0
10038171003817100381710038171205881003817100381710038171003817 119889119904)
100381710038171003817100381712059510038171003817100381710038172 (31)
then we have
10038171003817100381710038171205881003817100381710038171003817 le 119862ℎ
2(1199062 + int
119905
0
1199062119889119904) + 119862(int
119905
0
10038171003817100381710038171205881003817100381710038171003817 119889119904) (32)
Finally an application of Gronwallrsquos lemma yields the firstestimate
The second inequality follows in a similar fashion
6 Journal of Mathematics
Lemma7 There exists a constant119862 independent of ℎ such that
100381710038171003817100381712058810038171003817100381710038170119901
+ ℎ100381710038171003817100381712058810038171003817100381710038171119901
le 119862ℎ2(1199062119901 + int
119905
0
1199062119901119889119904) (33)
Proof Let 120588119909be an arbitrary component of nabla120588 with 119901 and
119902 conjugate indices we have 120588119909119901
= sup(120588119909 120593) 120593 isin
Cinfin
0(Ω) 120593
119902= 1
For any such 120593 let 120595 be the solution of
119860lowast(119905 120595 V) = minus (120593
119909 V) forallV isin 119867
1
0(Ω)
120595 = 0 on 120597Ω
(34)
It follows from the regularity theory for the elliptic problemthat
100381710038171003817100381712059510038171003817100381710038171119902
le 119862119901
10038171003817100381710038171205931003817100381710038171003817119902
= 119862119901 (35)
We then have by application of (21) that
(120588119909 120593) = 119860 (119905 120588 120595) = 119860 (119905 120588 120595 minus 119877
ℎ120595)
+ 119860 (119905 120588 119877ℎ120595 minus 119868
lowast
ℎ(119877
ℎ120595))
+ int
119905
0
119861 (119905 119904 120588 (119904) 119868lowast
ℎ(119877
ℎ120595)) 119889119904
= 1198681+ 119868
2+ 119868
3
119860 (119905 120588 120595 minus 119877ℎ120595) = 119860 (119905 119877
ℎ119906 minus 119906 120595)
= minus ((119877ℎ119906 minus 119906)
119909 120593) le 119862ℎ1199062119901
(36)
Applying Lemma 4 we have
1198682= 119860 (119905 119906 119877
ℎ120595 minus 119868
lowast
ℎ(119877
ℎ120595)) minus 119860 (119905 119881
ℎ119906 119877
ℎ120595 minus 119868
lowast
ℎ(119877
ℎ120595))
le 119862ℎ1199062119901
(37)
Finally 1198683is estimated as follows
1198683= int
119905
0
119861 (119905 119904 120588 (119904) 119868lowast
ℎ(119877
ℎ120595)) 119889119904 le 119862
119901int
119905
0
100381710038171003817100381712058810038171003817100381710038171119901
119889119904 (38)
Combining these estimates we get
100381710038171003817100381712058810038171003817100381710038171119901
le 119862ℎ1199062119901 + 119862119901int
119905
0
100381710038171003817100381712058810038171003817100381710038171119901
119889119904 (39)
hence by Gronwallrsquos lemma
100381710038171003817100381712058810038171003817100381710038171119901
le 119862ℎ(1199062119901 + int
119905
0
1199062119901119889119904) (40)
The derivation of the error estimate in 119871119901 is similar to the casewhen 119901 = 2
4 Error Estimates forSemidiscrete Approximations
We split the error 119890(119905) = 119906(119905) minus 119906ℎ(119905) as follows
119890 (119905) = (119906 (119905) minus 119881ℎ119906 (119905)) + (119881
ℎ119906 (119905) minus 119906
ℎ(119905)) = 120588 + 120579 (41)
It is easy to see that 120579 = 119881ℎ119906(119905) minus 119906
ℎ(119905) isin 119878
ℎsatisfies an
error equation of the form
(120579119905 119868
lowast
ℎVℎ) + 119860 (119905 120579 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎVℎ) 119889119904
= minus (120588119905 119868
lowast
ℎVℎ) V
ℎisin 119878
ℎ
(42)
Since the estimates of 120588 are already known it is enoughto have estimates for 120579
We will prove a sequence of lemmas which lead to thefollowing result
Lemma8 There is a positive constant119862 independent of ℎ suchthat
|||120579 (119905)||| le 119862(|||120579 (0)|||2+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817 119889119904) (43)
Proof Since 120579 isin 119878ℎwe may take V
ℎ= 120579 in (42) to obtain
1
2
119889
119889119905|||120579 (119905)|||
2+ 119888120579
2
1le
10038171003817100381710038171205881199051003817100381710038171003817 120579 + 119862int
119905
0
12057911198891199041205791
le1003817100381710038171003817120588119905
1003817100381710038171003817 120579 +1
2119888120579
2
1+ 119862int
119905
0
1205792
1119889119904
(44)
and hence by integration and Lemma 1 we have
||120579 (119905)||2+ int
119905
0
1205792
1119889119904
le 119862(|||120579 (0)|||2+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817 120579 119889119904 + int
119905
0
int
119904
0
120579 (120591)2
1119889120591119889119904)
(45)
Gronwallrsquos lemma now implies the following
|||120579 (119905)|||2+ int
119905
0
1205792
1119889119904 le 119862(|||120579 (0)|||
2+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817 120579 119889119904)
le 119862|||120579 (0)|||2+1
2sup119904le119905
120579 (119904)2
+ (int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817 119889119904)
2
(46)
Since this holds for all isin 119869 we may conclude that
||120579 (119905)|| le 119862(|||120579 (0)||| + int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817 119889119904) (47)
Journal of Mathematics 7
Remark 9 If the initial value was chosen so that 1199060ℎminus 119906
0 le
119862ℎ2119906
02 then 120579(0) le 119906
0ℎminus119906
0+119881
ℎ1199060minus119906
0 le 119862ℎ
2119906
02
One can derive
|||120579 (119905)||| le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (48)
Lemma 10 There is a positive constant 119862 independent of ℎsuch that
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
119889119904 + 1205792
1le 119862(120579 (0)
2
1+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
2
119889119904) (49)
Proof Set Vℎ= 120579
119905in (42) to get
10038171003817100381710038171205791199051003817100381710038171003817
2
+1
2
119889
119889119905119860 (119905 120579 119868
lowast
ℎ120579)
= minus (120588119905 119868
lowast
ℎ120579119905) minus int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579119905(119905)) 119889119904
+1
2119860
119905(119905 120579 119868
lowast
ℎ120579)
+1
2[119860 (119905 120579
119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)]
le1
2
10038171003817100381710038171205881199051003817100381710038171003817
2
+1
2
1003816100381610038161003816
1003816100381610038161003816
10038161003816100381610038161205791199051003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816
2
+ 119860119905(119905 120579 119868
lowast
ℎ120579)
+1
2[119860 (119905 120579
119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)]
minus119889
119889119905int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579 (119905)) 119889119904
+ 119861 (119905 119905 120579 (119905) 119868lowast
ℎ120579 (119905)) + int
119905
0
119861119905(119905 119904 120579 (119904) 119868
lowast
ℎ120579 (119905)) 119889119904
(50)
Then
10038171003817100381710038171205791199051003817100381710038171003817
2
+119889
119889119905119860 (119905 120579 119868
lowast
ℎ120579)
le1003817100381710038171003817120588119905
1003817100381710038171003817
2
minus119889
119889119905int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579) 119889119904
+ 119862(1205792
1+ int
119905
0
120579 (119904)2
1119889119904)
+1
2[119860 (119905 120579
119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)]
(51)
In addition recall that
119860 (119905 119906ℎ 119868
lowast
ℎVℎ) minus 119860 (119905 V
ℎ 119868
lowast
ℎ119906ℎ) le 119862ℎ
1003817100381710038171003817119906ℎ
10038171003817100381710038171
1003817100381710038171003817Vℎ10038171003817100381710038171
forall119906ℎ V
ℎisin 119878
ℎ
(52)
then applying an inverse inequality and using kickbackargument we obtain
[119860 (119905 120579119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)] le 119862ℎ
100381710038171003817100381712057911990510038171003817100381710038171
1205791 le 1198621003817100381710038171003817120579119905
1003817100381710038171003817 1205791
le 1205761003817100381710038171003817120579119905
1003817100381710038171003817
2
+ 1198621205792
1
(53)
Combining these estimates we derive
10038171003817100381710038171205791199051003817100381710038171003817
2
+119889
119889119905119860 (119905 120579 119868
lowast
ℎ120579)
le1003817100381710038171003817120588119905
1003817100381710038171003817
2
minus119889
119889119905int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579) 119889119904
+ 119862(1205792
1+ int
119905
0
120579 (119904)2
1119889119904)
(54)
So after integration in time and using the weak coercivity of119860(119905 120579 119868
lowast
ℎ120579) we get
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
119889119904 + 1198880120579
2
1
le 1198880120579 (0)
2
1+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
2
119889119904
+ int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579) 119889119904 + 119862int
119905
0
120579 (119904)2
1119889119904
le 1198880120579 (0)
2
1+119888
2120579
2
1+ 119862(int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
2
+ 120579 (119904)2
1119889119904)
(55)
and by Gronwallrsquos lemma
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
119889119904 + 1198881205792
1le 119862(120579 (0)
2
1+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
2
119889119904) (56)
Remark 11 If 120579(0) = 0 then
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
119889119904 + 1198881205792
1le 119862ℎ
2(int
119905
0
1003817100381710038171003817119906119905
1003817100381710038171003817
2
2119889119904) (57)
Theorem 12 (error estimates in 1198712 and1198671-norms) Let 119906 119906
ℎ
be the solutions of (2) and (11) respectively Assume that 119906 119906119905isin
119871infin(119867
1
0cap 119867
2)
(a) Let 1199060ℎ
be chosen so that 1199060ℎ
minus 1199060 le 119862ℎ
2119906
02
Then for 119879 gt 0 fixed there is a constant 119862 = 119862(119879)
independent of ℎ such that for all 0 lt 119905 lt 119879
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905)
1003817100381710038171003817 le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (58)
(b) Let 1199060ℎ
be chosen so that 1199060ℎminus 119906
01
le 119862ℎ11990602
Then for 119879 gt 0 fixed there is a constant 119862 = 119862(119879)
independent of ℎ such that for all 0 lt 119905 lt 119879
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905))
10038171003817100381710038171le 119862ℎ(
10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (59)
We now prove error estimates for FVE approximations in119871119901 and119882
1119901-norms
8 Journal of Mathematics
Theorem 13 (error estimates in 119871119901 and 119882
1119901-norms) Let119906 119906
ℎbe the solutions of (2) and (11) respectively and 119906
0ℎ=
119881ℎ1199060 Assume that 119906 119906
119905isin 119871
infin(119867
1
0cap 119882
2119901) For ℎ sufficiently
small we have
1003817100381710038171003817119906 minus 119906ℎ
10038171003817100381710038170119901le 119862ℎ
2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
1003817100381710038171003817119906 minus 119906ℎ
10038171003817100381710038171119901le 119862ℎ(
10038171003817100381710038171199060
10038171003817100381710038172+ 1199062119901 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
(60)
Proof If 2 le 119901 lt infin by the following Sobolev embeddinginequality
1205790119901 le 1198621205791 (61)
then the first desired estimate follows from Lemmas 7 and 10Given 120593 isin Cinfin
0(Ω) find 120595 isin 119867
1
0(Ω) such that
119860(119905)lowast120595 = minus120593
119909 in Ω
120595 = 0 on 120597Ω
100381710038171003817100381712059510038171003817100381710038171119902
le100381710038171003817100381712059310038171003817100381710038170119902
(62)
We have
((119906 minus 119906ℎ)119909 120593) = 119860 (119905 119906 minus 119906
ℎ 120595) = 119860 (119905 119906 minus 119906
ℎ 120595 minus 119877
ℎ120595)
+ 119860 (119905 119906 minus 119906ℎ 119877
ℎ120595 minus 119868
lowast
ℎ119877ℎ120595)
minus int
119905
0
119861 (119905 119904 (119906 minus 119906ℎ) (119904) 119868
lowast
ℎ119877ℎ120595) 119889119904
minus ((119906 minus 119906ℎ)119905 119868
lowast
ℎ119877ℎ120595)
= 1198681+ 119868
2+ 119868
3+ 119868
4
100381610038161003816100381611986811003816100381610038161003816 le
1003816100381610038161003816119860 (119905 119906 minus 119877ℎ119906 120595)
1003816100381610038161003816 le 1198621003817100381710038171003817119906 minus 119877
ℎ11990610038171003817100381710038171119901
100381710038171003817100381712059510038171003817100381710038171119902
le 119862ℎ11990621199011003817100381710038171003817120595
10038171003817100381710038171119902
(63)
By Lemma 4
100381610038161003816100381611986821003816100381610038161003816 le 119860 (119905 119906 minus 119906
ℎ 119877
ℎ120595 minus 119868
lowast
ℎ119877ℎ120595)
le 119862ℎ (1003816100381610038161003816119906 minus 119906
ℎ
10038161003816100381610038161119901+ |119906|2119901)
100381710038171003817100381712059510038171003817100381710038171119902
100381610038161003816100381611986831003816100381610038161003816 le int
119905
0
1003817100381710038171003817119906 minus 119906ℎ
100381710038171003817100381711199011198891199041003817100381710038171003817120595
10038171003817100381710038171119902
100381610038161003816100381611986841003816100381610038161003816 le (
1003817100381710038171003817119906 minus 119906ℎ
1003817100381710038171003817)1003817100381710038171003817120595
1003817100381710038171003817 le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
100381710038171003817100381712059510038171003817100381710038171119902
(64)
where we have used the fact 120595 le 1205951119903 119903 gt 1 Combining
these estimates we get
1003816100381610038161003816((119906 minus 119906ℎ)119909 120593)
1003816100381610038161003816 le 119862ℎ(10038171003817100381710038171199060
10038171003817100381710038172+ 1199062119901 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
100381710038171003817100381712059510038171003817100381710038171119902
1003817100381710038171003817(119906 minus 119906ℎ)119909
10038171003817100381710038170119901= sup
((119906 minus 119906ℎ)119909 120593)
100381710038171003817100381712059310038171003817100381710038170119902
le 119862ℎ1003816100381610038161003816119906 minus 119906
ℎ
10038161003816100381610038161119901
+ 119862ℎ(10038171003817100381710038171199060
10038171003817100381710038172+ 1199062119901 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
(65)
Hence using the Poincare inequality we have for ℎ sufficientlysmall
1003817100381710038171003817119906 minus 119906ℎ
10038171003817100381710038171119901le 119862ℎ(
10038171003817100381710038171199060
10038171003817100381710038172+ 1199062119901 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (66)
We compare the relationship between covolume solutionand the Galerkin finite element solution
Corollary 14 Let ℎbe the finite element solution to (2) that
is
(ℎ119905 V
ℎ) + 119860 (119905
ℎ V
ℎ)
+ int
119905
0
119861 (119905 119904 ℎ(119904) V
ℎ) 119889119904 = (119891 V
ℎ) V
ℎisin 119878
ℎ
ℎ(0) = 119877
ℎ1199060
(67)
For ℎ sufficiently small we have
1003817100381710038171003817(ℎminus 119906
ℎ)10038171003817100381710038171119901
le 119862(
ℎ1003817100381710038171003817119906 minus 119906
ℎ
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus 119906
ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817
+int
119905
0
(1003817100381710038171003817(119906 minus 119906
ℎ) (119904)
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus
ℎ) (119904)
10038171003817100381710038171119901) 119889119904
)
le 119862 (119906) ℎ
(68)
Proof By (2) and (67)
((ℎminus 119906)
119905 V
ℎ) + 119860 (119905
ℎminus 119906 V
ℎ)
+ int
119905
0
119861 (119905 119904 (ℎminus 119906) (119904) V
ℎ) 119889119904 = 0 V
ℎisin 119878
ℎ
(69)
Consider the following auxiliary problem For any such 120593 let120595 be the solution of the following
119860(119905)lowast120595 = minus120593
119909 in Ω
120595 = 0 on 120597Ω
(70)
Journal of Mathematics 9
with1003817100381710038171003817120595
10038171003817100381710038171119902le100381710038171003817100381712059310038171003817100381710038170119902
((ℎminus 119906
ℎ)119909 120593)
= 119860 (119905 ℎminus 119906
ℎ 120595)
= 119860 (119905 ℎminus 119906
ℎ 120595 minus 119877
ℎ120595) + 119860 (119905 119906 minus 119906
ℎ 119877
ℎ120595)
minus 119860 (119905 119906 minus 119906ℎ 119868
lowast
ℎ119877ℎ120595) minus ((119906 minus 119906
ℎ)119905 119868
lowast
ℎ119877ℎ120595)
minus int
119905
0
119861 (119905 119904 (119906 minus 119906ℎ) (119904) 119868
lowast
ℎ119877ℎ120595) 119889119904
+ 119860 (119905 ℎminus 119906 119877
ℎ120595)
= [119860 (119905 119906 minus 119906ℎ 119877
ℎ120595) minus 119860 (119905 119906 minus 119906
ℎ 119868
lowast
ℎ119877ℎ120595)]
minus ((119906 minus 119906ℎ)119905 119868
lowast
ℎ119877ℎ120595) minus ((
ℎminus 119906)
119905 119877
ℎ120595)
minus int
119905
0
119861 (119905 119904 (119906 minus 119906ℎ) (119904) 119868
lowast
ℎ119877ℎ120595) 119889119904
minus int
119905
0
119861 (119905 119904 (ℎminus 119906) (119904) 119877
ℎ120595) 119889119904
= 1198681+ 119868
2+ 119868
3
(71)
On the other hand10038161003816100381610038161198681
1003816100381610038161003816 le 119862ℎ1003817100381710038171003817119906 minus 119906
ℎ
10038171003817100381710038171119901
100381710038171003817100381712059510038171003817100381710038171119902
100381610038161003816100381611986821003816100381610038161003816 le 119862 (
1003817100381710038171003817(119906 minus 119906ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817)1003817100381710038171003817120595
1003817100381710038171003817
le 119862 (1003817100381710038171003817(119906 minus 119906
ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817)1003817100381710038171003817120595
10038171003817100381710038171119902
(72)
where we have used the fact 120595 le 1205951119903 119903 gt 1
100381610038161003816100381611986831003816100381610038161003816 le int
119905
0
(1003817100381710038171003817(119906 minus 119906
ℎ) (119904)
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus
ℎ) (119904)
10038171003817100381710038171119901) 119889119904
100381710038171003817100381712059510038171003817100381710038171119902
1003817100381710038171003817(ℎminus 119906
ℎ)119909
10038171003817100381710038170119901
= sup120593isinCinfin0
((ℎminus 119906
ℎ)119909 120593)
100381710038171003817100381712059310038171003817100381710038170119902
le 119862(
ℎ1003817100381710038171003817119906 minus 119906
ℎ
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus 119906
ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817
+int
119905
0
(1003817100381710038171003817(119906 minus 119906
ℎ) (119904)
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus
ℎ) (119904)
10038171003817100381710038171119901) 119889119904
)
(73)
We deduce the result from the known finite element esti-mates
Remark 15 In order to estimate (119906 minus 119906ℎ)119905 by differentiating
(42) with respect to 119905 we obtain
(120579119905119905 119868
lowast
ℎVℎ) + 119860 (119905 120579
119905 119868
lowast
ℎVℎ) + 119860
119905(119905 120579
119905 119868
lowast
ℎVℎ)
+ 119861 (119905 119905 120579 119868lowast
ℎVℎ) + int
119905
0
119861119905(119905 119904 120579 (119904) 119868
lowast
ℎVℎ) 119889119904
= minus (120588119905119905 119868
lowast
ℎVℎ)
(74)
Setting Vℎ= 120579
119905 we obtain
1
2
119889
119889119905
1003816100381610038161003816
1003816100381610038161003816
10038161003816100381610038161205791199051003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816
2
+ 1198881003817100381710038171003817120579119905
1003817100381710038171003817
2
1le1003817100381710038171003817120588119905119905
1003817100381710038171003817
10038171003817100381710038171205791199051003817100381710038171003817
+1
21198881003817100381710038171003817120579119905
1003817100381710038171003817
2
1+ 119862120579
2
1+ int
119905
0
1205792
1119889119904
le1003817100381710038171003817120588119905119905
1003817100381710038171003817
10038171003817100381710038171205791199051003817100381710038171003817 +
1
21198881003817100381710038171003817120579119905
1003817100381710038171003817
2
1+ 119862int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
1119889119904
(75)
Using kickback argument integrating and applying Gron-wallrsquos lemma we deduce
10038171003817100381710038171205791199051003817100381710038171003817 le 119862(
1003817100381710038171003817120579119905 (0)1003817100381710038171003817 + int
119905
0
100381710038171003817100381712058811990511990510038171003817100381710038171119889119904)
le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+10038171003817100381710038171199061
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904)
(76)
5 The Lumped Mass Finite VolumeElement Method
In this section we restrict our study to the 2D case A simpleway to define the lumped mass scheme [21] is to replace themass matrix 119872
ℎin (14) by the diagonal matrix 119872
ℎobtained
by taking for its diagonal elements the numbers 119872ℎ119894119894
=
sum119873ℎ
119895=1119872
ℎ119894119895or by lumping all masses in one row into the
diagonal entryThismakes the inversion of thematrix in frontof1205721015840
(119905) a trivialityWewill therefore study thematrix problem
119872ℎ1205721015840(119905) + 119860
ℎ(119905) 120572 (119905) + int
119905
0
119861ℎ(119905 119904) 120572 (119904) 119889119904 = 119865
ℎ(119905) (77)
We know that the lumped mass method defined by (77)above is equivalent to
(119868lowast
ℎ119906ℎ119905 119868
lowast
ℎVℎ) + 119860 (119905 119906
ℎ 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 119906ℎ(119904) 119868
lowast
ℎVℎ) 119889119904
= (119891 119868lowast
ℎVℎ) V
ℎisin 119878
ℎ
(78)
Our alternative interpretation of this procedure will beto think of (77) as being obtained by evaluating the firstterm in (78) by numerical quadrature Let 119870 be a triangle ofthe triangulation 119879
ℎ let 119909
119895 119895 = 1 2 3 be its vertices and
consider the quadrature formula
119876119870ℎ
(119891) =1
3area119870
3
sum
119895=1
119891 (119909119895) ≃ int
119870
119891119889119909 (79)
We may then define the associated bilinear form in 119878ℎtimes
119878lowast
ℎ using the quadrature scheme by the following
(Vℎ 120578
ℎ)ℎ= sum
119870isin119879ℎ
119876119870ℎ
(Vℎ120578ℎ) = sum
119909119894isin119873119886
ℎ
Vℎ(119909
119894) 120578
ℎ(119909
119894)10038161003816100381610038161003816119881119909119894
10038161003816100381610038161003816
forallVℎisin 119878
ℎ 120578
ℎisin 119878
lowast
ℎ
(80)
10 Journal of Mathematics
We note that Vℎ2
ℎ= (V
ℎ 119868
lowast
ℎVℎ)ℎis a norm in 119878
ℎwhich is
equivalent to the 1198712-norm uniformly in ℎ that is there existtwo positive constants 119862
1and 119862
2such that for all V
ℎisin 119878
ℎ we
have
1198620
1003817100381710038171003817Vℎ1003817100381710038171003817 le
1003817100381710038171003817Vℎ1003817100381710038171003817ℎ
le 1198621
1003817100381710038171003817Vℎ1003817100381710038171003817 forallV
ℎisin 119878
ℎ (81)
We note that the aforementioned definition (Vℎ 120578
ℎ)ℎmay
be used also for 120578ℎisin 119878
ℎand that (V
ℎ 119908
ℎ)ℎ= (V
ℎ 119868
lowast
ℎ119908
ℎ)ℎfor
Vℎ 119908
ℎisin 119878
ℎ
The lumpedmass method defined by (78) is equivalent to
(119906ℎ119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 119906
ℎ 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 119906ℎ(119904) 119868
lowast
ℎVℎ) 119889119904
= (119891 119868lowast
ℎVℎ) V
ℎisin 119878
ℎ
(82)
We introduce the quadrature error
120576ℎ(V
ℎ 119908
ℎ) = (V
ℎ 119908
ℎ)ℎminus (V
ℎ 119908
ℎ) (83)
Lemma 16 (see [21]) Let Vℎ 119908
ℎisin 119878
ℎ Then
1003816100381610038161003816120576ℎ (Vℎ 119908ℎ)1003816100381610038161003816 le 119862ℎ
2 1003817100381710038171003817nablaVℎ1003817100381710038171003817
1003817100381710038171003817nabla119908ℎ
1003817100381710038171003817 (84)
Theorem 17 Let 119906ℎand 119906 be the solutions of (82) and (2)
respectively and assume 119906ℎ(0) = 119877
ℎ1199060 Then we have for the
error in the lumped mass semidiscrete method for 119905 ge 0 thefollowing
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905)
1003817100381710038171003817 le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ 1199062 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (85)
Proof In order to estimate 120579 we write
(120579119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 120579 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎVℎ) 119889119904
= (119906ℎ119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 119906
ℎ 119868
lowast
ℎVℎ)
+ int
119905
0
119861 (119905 119904 119906ℎ(119904) 119868
lowast
ℎVℎ) 119889119904
minus ((119881ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus 119860 (119905 119881
ℎ119906 119868
lowast
ℎVℎ)
minus int
119905
0
119861 (119905 119904 119881ℎ119906 (119904) 119868
lowast
ℎVℎ) 119889119904
= (119891 119868lowast
ℎVℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus 119860 (119905 119906 119868
lowast
ℎVℎ)
minus int
119905
0
119861 (119905 119904 119906 (119904) 119868lowast
ℎVℎ)
= (119906119905 119868
lowast
ℎVℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)ℎ
= minus (120588119905 119868
lowast
ℎVℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)ℎ+ ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
(86)
We rewrite
((119881ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
= ((119881ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus ((119881
ℎ119906)
119905 V
ℎ)
+ ((119881ℎ119906)
119905 V
ℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
= 120576ℎ((119881
ℎ119906)
119905 V
ℎ) + ((119881
ℎ119906)
119905 V
ℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
(120579119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 120579 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎVℎ) 119889119904
= minus (120588119905 119868
lowast
ℎVℎ) + 120576
ℎ((119881
ℎ119906)
119905 V
ℎ)
+ ((119881ℎ119906)
119905 V
ℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
(87)
Setting Vℎ= 120579 in (87) we obtain
1
2
119889
119889119905120579
2
ℎ+ 119888
01205792
1
le1003817100381710038171003817120588119905
1003817100381710038171003817 120579 +1
21198880120579
2
1+ 119862int
119905
0
1205792
1119889119904
+ 120576ℎ((119881
ℎ119906)
119905 120579) + ((119881
ℎ119906)
119905 120579) minus ((119881
ℎ119906)
119905 119868
lowast
ℎ120579)
(88)
Using Lemma 16 and the inverse estimate we get1003816100381610038161003816120576ℎ (119881ℎ
119906119905 120579)
1003816100381610038161003816 le 119862ℎ2 1003817100381710038171003817nabla(119881ℎ
119906)119905
1003817100381710038171003817 nabla120579
le 119862ℎ2 1003817100381710038171003817nabla119906119905
1003817100381710038171003817 nabla120579
le 119862ℎ1003817100381710038171003817nabla119906119905
1003817100381710038171003817 120579
(89)
we have1003816100381610038161003816((119881ℎ
119906)119905 120579) minus ((119881
ℎ119906)
119905 119868
lowast
ℎ120579)1003816100381610038161003816 le 119862ℎ
1003817100381710038171003817nabla119906119905
1003817100381710038171003817 120579 (90)
Using Youngrsquos inequality and Gronwallrsquos lemma to eliminate120579
1on the right-hand side and using integration in 119905 we get
the result
1
2
119889
119889119905120579
2
ℎ+ 119888
0 120579 le1003817100381710038171003817120588119905
1003817100381710038171003817 120579 + 119862ℎ1003817100381710038171003817nabla119906119905
1003817100381710038171003817 120579 (91)
Using Youngrsquos inequality to eliminate 120579 on the right handside it becomes
Using integration in 119905 we get the result
We will now show that the 1198671-norm error bound of
theorem remains valid for the lumped mass method (82)
Theorem 18 Let 119906ℎand 119906 be the solutions of (82) and (2)
respectively and assume
119906ℎ(0) = 119877
ℎ1199060
10038171003817100381710038171199061ℎ(0) minus 119906
1
1003817100381710038171003817 le 119862ℎ210038171003817100381710038171199061
10038171003817100381710038172 (92)
Then we have for the error in the lumped mass semidiscretemethod for 119905 ge 0 the following
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905)
10038171003817100381710038171le 119862ℎ
2(10038171003817100381710038171199060
10038171003817100381710038172+10038171003817100381710038171199061
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904)
(93)
Journal of Mathematics 11
Proof Setting Vℎ= 120579
119905in (87) we obtain
10038171003817100381710038171205791199051003817100381710038171003817
2
ℎ+1
2
119889
119889119905119860 (119905 120579 119868
lowast
ℎ120579)
=1
2119860
119905(119905 120579 119868
lowast
ℎ120579) +
1
2[119860 (119905 120579
119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)]
119861 (119905 119905 120579 (119905) 119868lowast
ℎ120579 (119905)) + int
119905
0
119861119905(119905 119904 120579 (119904) 119868
lowast
ℎ120579 (119905)) 119889119904
minus119889
119889119905int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579 (119905)) 119889119904 minus (120588
119905 119868
lowast
ℎ120579119905)
minus 120576ℎ((119881
ℎ119906)
119905 120579
119905) + ((119881
ℎ119906)
119905 120579) minus ((119881
ℎ119906)
119905 119868
lowast
ℎ120579)
(94)
It follows thus that using integration in 119905 and Gronwallrsquoslemma we have
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
ℎ+ 120579
2
1le 119862nabla120579 (0)
2+ 119862int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
10038171003817100381710038171205791199051003817100381710038171003817 119889119904
+ 119862ℎ2int
119905
0
1003817100381710038171003817119906119905
1003817100381710038171003817
2
1119889119904
(95)
6 Full Discretization
Let 120597119880119899= (119880
119899minus119880
119899minus1)119896 be the backward difference quotient
of 119880119899 assume that 119860ℎ
= 119875ℎ119860 is a discrete analogue of 119860
(similarly 119861ℎ
= 119875ℎ119861) where 119875
ℎ 119871
2(Ω) rarr 119878
lowast
ℎthe 119871
2
projection is defined by
(119875ℎV 119868lowast
ℎVℎ) = (V 119868lowast
ℎVℎ) V isin 119871
2(Ω) V
ℎisin 119878
ℎ (96)
In order to define fully discrete approximation of (11) wediscretize the time by taking 119905
119899= 119899119896 119896 gt 0 119899 = 1 2 and
use the numerical quadrature
int
119905119899minus12
0
119892 (119904) 119889119904 asymp
119899
sum
119896=1
120596119899119896119892 (119905
119896minus12) 119905
119899minus12= (119899 minus
1
2) 119896
(97)
Here 120596119899119896 are the integrationweights andwe assume that
the following error estimate is valid
119902119899(119892) = int
119905119899minus12
0
119892 (119904) 119889119904minus
119899
sum
119896=1
120596119899119896119892 (119905
119896minus12)
le 1198621198962int
119905119899
0
(10038161003816100381610038161003816119892101584010038161003816100381610038161003816+100381610038161003816100381610038161198921015840101584010038161003816100381610038161003816) 119889119904
(98)
Now define our complete discrete FVE approximation of(11) by the following find 119880
119899isin 119878
ℎfor 119899 = 1 2 such that
for all Vℎisin 119878
ℎ
(120597119880119899 119868
lowast
ℎVℎ) + 119860 (119905
119899minus12 119880
119899minus12 119868
lowast
ℎVℎ)
+
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12 119880
119896minus12 119868
lowast
ℎVℎ)
= (119891119899minus12
119868lowast
ℎVℎ)
1198800 in 119878
ℎ
(99)
where 119880119899minus12= (119880
119899+ 119880
119899minus1)2
Theorem 19 Let 119906(119905) and 119880119899 be the solutions of problem (2)
and its complete discrete scheme (99) respectively Then forany 119879 gt 0 there exists a positive constant 119862 = 119862(119879) gt 0independent of ℎ such that for 0 lt 119905
119899le 119879
1003817100381710038171003817119906 (119905119899) minus 1198801198991003817100381710038171003817
le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905119899
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
+ 1198621198962(int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905119905
1003817100381710038171003817) 119889119904)
(100)
Proof Let us split the error into two parts 119906(119905119899) minus 119880
119899= 120588
119899+
120579119899 where 120588
119899= 119906(119905
119899)minus119881
ℎ119906(119905
119899) and 120579119899 = 119881
ℎ119906(119905
119899)minus119880
119899 and let119882 = 119881
ℎ119906(119905) isin 119878
ℎbe the Ritz-Volterra projection of 119906 Then
from (2) and (99) we have for all Vℎisin 119878
ℎthe following
(120597120579119899 119868
lowast
ℎVℎ) + 119860 (119905
119899minus12 120579
119899minus12 119868
lowast
ℎVℎ)
+
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12 120579
119896minus12 119868
lowast
ℎVℎ)
= minus (119903119899 119868
lowast
ℎVℎ) forallV
ℎisin 119878
ℎ
(101)
where
119903119899= 119903
1
119899+ 119903
2
119899+ 119903
3
119899+ 119903
4
119899
1199031
119899= 120597120588
119899
1199032
119899= 120597119906 (119905
119899) minus 119906
119905(119905
119899minus12)
1199033
119899= 119860(119905
119899minus12(119906 (119905
119899) + 119906 (119905
119899minus1))
2minus 119906 (119905
119899minus12))
1199034
119899= 119902
119899(119861
ℎ119882)
=
119899
sum
119896=1
120596119899119896119861ℎ(119905
119899minus12 119905
119896minus12119882
119896minus12 119868
lowast
ℎVℎ)
minus int
119905119899minus12
0
119861 (119905119899 119904119882 (119904) 119868
lowast
ℎVℎ) 119889119904
(102)
In fact by Taylor expansion
119906119899+1
= 119906119899+ 119896119906
1015840(119905
119899) + int
119905119899+1
119905119899
11990610158401015840(119904) (119905
119899+1minus 119904) 119889119904
= 119906119899+ 119896119906
1015840(119905
119899) +
1198962
211990610158401015840(119905
119899) +
1198963
6119906(3)
(119905119899)
+1
6int
119905119899+1
119905119899
119906(4)
(119904) (119905119899+1
minus 119904)3
119889119904
(103)
12 Journal of Mathematics
we have100381710038171003817100381710038171199031
119899
10038171003817100381710038171003817=
10038171003817100381710038171003817120597120588
11989910038171003817100381710038171003817le
1
119896int
119905119899
119905119899minus1
10038171003817100381710038171205881199051003817100381710038171003817 119889119904 le 119862
ℎ2
119896int
119905119899
119905119899minus1
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
100381710038171003817100381710038171199032
119899
10038171003817100381710038171003817=
10038171003817100381710038171003817120597119906 (119905
119899) minus 119906
119905(119905
119899minus12)10038171003817100381710038171003817
=1
119896
100381710038171003817100381710038171003817100381710038171003817
int
119905119899
119905119899minus1
(119906119905(119904) minus 119906
119905(119905
119899minus12)) 119889119904
100381710038171003817100381710038171003817100381710038171003817
le 119862119896int
119905119899
119905119899minus1
10038171003817100381710038171003817119906(3)
(119904)10038171003817100381710038171003817119889119904
100381710038171003817100381710038171199033
119899
10038171003817100381710038171003817=
100381710038171003817100381710038171003817100381710038171003817
119860(119905119899minus12
119906 (119905
119899) + 119906 (119905
119899minus1)
2minus 119906 (119905
119899minus12) 119868
lowast
ℎVℎ)
100381710038171003817100381710038171003817100381710038171003817
le 119862119896int
119905119899
119905119899minus1
1003817100381710038171003817119860119906119905119905(119904)
1003817100381710038171003817 119889119904 le 119862119896int
119905119899
119905119899minus1
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
(104)
In addition the quadrature error satisfies100381710038171003817100381710038171199034
119899
10038171003817100381710038171003817= 119902
119899minus12(119861
ℎ119882)
=
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12119882
119896minus12 119868
lowast
ℎVℎ)
minus int
119905119899minus12
0
119861 (119905119899 119904119882 (119904) 119868
lowast
ℎVℎ) 119889119904
le 1198621198962int
119905119899
0
1003817100381710038171003817(119861ℎ119882)
119904119904
1003817100381710038171003817 119889119904
le 1198621198962int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172) 119889119904
119896
119873
sum
119899=1
10038171003817100381710038171199031198991003817100381710038171003817 le 119862ℎ
2int
119905119899
0
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
+ 1198621198962int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172+10038171003817100381710038171003817119906(3)10038171003817100381710038171003817
) 119889119904
(105)
Taking Vℎ= 120579
119899minus12 in (101) and noting that (120597120579119899 119868lowastℎ120579119899minus12
) =
(12)120597|||120579119899|||
2 there is1003816100381610038161003816
1003816100381610038161003816
10038161003816100381610038161205791198991003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816
2
minus10038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus110038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
+ 211989611988810038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus1210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
1
le 1198621198962
119899
sum
119896=1
10038171003817100381710038171003817120579119896minus12100381710038171003817100381710038171
10038171003817100381710038171003817120579119899minus12100381710038171003817100381710038171
+ 1198621198961003817100381710038171003817119903119899
1003817100381710038171003817
10038171003817100381710038171003817120579119899minus1210038171003817100381710038171003817
le11989611988810038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus1210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
1+ 119862119896
2
119899
sum
119896=1
10038171003817100381710038171003817120579119896minus1210038171003817100381710038171003817
2
1+ 119862119896
10038171003817100381710038171199031198991003817100381710038171003817
10038171003817100381710038171003817120579119899minus1210038171003817100381710038171003817
(106)
Summing from 119899 = 1 to 119873 and then after cancelling thecommon factor and using Gronwallrsquos lemma we obtain
10038161003816100381610038161003816
10038161003816100381610038161003816
1003816100381610038161003816100381612057911987310038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
le 11986210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579010038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
+ 119862119896
119873
sum
119896=1
10038171003817100381710038171199031198991003817100381710038171003817 (
1003817100381710038171003817100381712057911989610038171003817100381710038171003817
+10038171003817100381710038171003817120579119896minus1210038171003817100381710038171003817
) (107)
and then
10038161003816100381610038161003816
10038161003816100381610038161003816
1003816100381610038161003816100381612057911987310038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816le 119862
10038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579010038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816+ 119862119896
119873
sum
119899=1
10038171003817100381710038171199031198991003817100381710038171003817
(108)
the theorem follows from the estimates of 120588119899 and 119903119899
References
[1] Z Q Cai ldquoOn the finite volume element methodrdquo NumerischeMathematik vol 58 no 7 pp 713ndash735 1991
[2] S H Chou and D Y Kwak ldquoAnalysis and convergence of aMAC-like scheme for the generalized Stokes problemrdquo Numer-ical Methods for Partial Differential Equations vol 13 no 2 pp147ndash162 1997
[3] P Chatzipantelidis ldquoA finite volume method based on theCrouzeix-Raviart element for elliptic PDErsquos in two dimensionsrdquoNumerische Mathematik vol 82 no 3 pp 409ndash432 1999
[4] P Chatzipantelidis ldquoFinite volumemethods for elliptic PDErsquos anew approachrdquo Mathematical Modelling and Numerical Analy-sis vol 36 no 2 pp 307ndash324 2002
[5] P Chatzipantelidis R D Lazarov and V Thomee ldquoErrorestimates for a finite volume element method for parabolicequations in convex polygonal domainsrdquoNumericalMethods forPartial Differential Equations vol 20 no 5 pp 650ndash674 2004
[6] R E Ewing R D Lazarov and Y Lin ldquoFinite volume elementapproximations of nonlocal in time one-dimensional flows inporous mediardquo Computing vol 64 no 2 pp 157ndash182 2000
[7] R Ewing R Lazarov and Y Lin ldquoFinite volume elementapproximations of nonlocal reactive flows in porous mediardquoNumericalMethods for Partial Differential Equations vol 16 no3 pp 285ndash311 2000
[8] R E Ewing T Lin andY Lin ldquoOn the accuracy of the finite vol-ume element method based on piecewise linear polynomialsrdquoSIAM Journal on Numerical Analysis vol 39 no 6 pp 1865ndash1888 2002
[9] R K Sinha and J Geiser ldquoError estimates for finite volumeelement methods for convection-diffusion-reaction equationsrdquoApplied Numerical Mathematics vol 57 no 1 pp 59ndash72 2007
[10] S H Chou ldquoAnalysis and convergence of a covolume methodfor the generalized Stokes problemrdquo Mathematics of Computa-tion vol 66 no 217 pp 85ndash104 1997
[11] M Berggren ldquoA vertex-centered dual discontinuous Galerkinmethodrdquo Journal of Computational and Applied Mathematicsvol 192 no 1 pp 175ndash181 2006
[12] S H Chou and D Y Kwak ldquoMultigrid algorithms for a vertex-centered covolume method for elliptic problemsrdquo NumerischeMathematik vol 90 no 3 pp 441ndash458 2002
[13] R Eymard T Gallouet and R Herbin Finite Volume MethodsHandbook of Numerical Analysis North-Holland AmsterdamThe Netherlands 2000
[14] V R Voller Basic Control Volume Finite Element Methods forFluids and Solids World Scientific Publishing 2009
[15] J Huang and S Xi ldquoOn the finite volume element method forgeneral self-adjoint elliptic problemsrdquo SIAM Journal on Numer-ical Analysis vol 35 no 5 pp 1762ndash1774 1998
[16] X Ma S Shu and A Zhou ldquoSymmetric finite volume discreti-zations for parabolic problemsrdquo Computer Methods in AppliedMechanics and Engineering vol 192 no 39-40 pp 4467ndash44852003
[17] R D Lazarov and S Z Tomov ldquoAdaptive finite volume elementmethod for convection-diffusion-reaction problems in 3-Drdquo inScientific Computing and Applications vol 7 of Advances inComputation Theory and Practice pp 91ndash106 Nova SciencePublishers Huntington NY USA 2001
[18] I DMishevFinite volume and finite volume elementmethods fornon-symmetric problems [PhD thesis] Texas AampM University1997 Technical Report ISC-96-04-MATH
Journal of Mathematics 13
[19] C Chen and T Shih Finite Element Methods for Integrodifferen-tial Equations World Scientific Publishing Singapore 1998
[20] Y P Lin V Thomee and L B Wahlbin ldquoRitz-Volterra pro-jections to finite-element spaces and applications to integrod-ifferential and related equationsrdquo SIAM Journal on NumericalAnalysis vol 28 no 4 pp 1047ndash1070 1991
[21] VThomeeGalerkin Finite Element Methods for Parabolic Prob-lems Springer Series in Computational Mathematics SpringerNew York NY USA 2006
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Differential EquationsInternational Journal of
Volume 2014
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Mathematical PhysicsAdvances in
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OptimizationJournal of
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Function Spaces
Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Algebra
Discrete Dynamics in Nature and Society
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Decision SciencesAdvances in
Discrete MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
Volume 2014 Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Stochastic AnalysisInternational Journal of
6 Journal of Mathematics
Lemma7 There exists a constant119862 independent of ℎ such that
100381710038171003817100381712058810038171003817100381710038170119901
+ ℎ100381710038171003817100381712058810038171003817100381710038171119901
le 119862ℎ2(1199062119901 + int
119905
0
1199062119901119889119904) (33)
Proof Let 120588119909be an arbitrary component of nabla120588 with 119901 and
119902 conjugate indices we have 120588119909119901
= sup(120588119909 120593) 120593 isin
Cinfin
0(Ω) 120593
119902= 1
For any such 120593 let 120595 be the solution of
119860lowast(119905 120595 V) = minus (120593
119909 V) forallV isin 119867
1
0(Ω)
120595 = 0 on 120597Ω
(34)
It follows from the regularity theory for the elliptic problemthat
100381710038171003817100381712059510038171003817100381710038171119902
le 119862119901
10038171003817100381710038171205931003817100381710038171003817119902
= 119862119901 (35)
We then have by application of (21) that
(120588119909 120593) = 119860 (119905 120588 120595) = 119860 (119905 120588 120595 minus 119877
ℎ120595)
+ 119860 (119905 120588 119877ℎ120595 minus 119868
lowast
ℎ(119877
ℎ120595))
+ int
119905
0
119861 (119905 119904 120588 (119904) 119868lowast
ℎ(119877
ℎ120595)) 119889119904
= 1198681+ 119868
2+ 119868
3
119860 (119905 120588 120595 minus 119877ℎ120595) = 119860 (119905 119877
ℎ119906 minus 119906 120595)
= minus ((119877ℎ119906 minus 119906)
119909 120593) le 119862ℎ1199062119901
(36)
Applying Lemma 4 we have
1198682= 119860 (119905 119906 119877
ℎ120595 minus 119868
lowast
ℎ(119877
ℎ120595)) minus 119860 (119905 119881
ℎ119906 119877
ℎ120595 minus 119868
lowast
ℎ(119877
ℎ120595))
le 119862ℎ1199062119901
(37)
Finally 1198683is estimated as follows
1198683= int
119905
0
119861 (119905 119904 120588 (119904) 119868lowast
ℎ(119877
ℎ120595)) 119889119904 le 119862
119901int
119905
0
100381710038171003817100381712058810038171003817100381710038171119901
119889119904 (38)
Combining these estimates we get
100381710038171003817100381712058810038171003817100381710038171119901
le 119862ℎ1199062119901 + 119862119901int
119905
0
100381710038171003817100381712058810038171003817100381710038171119901
119889119904 (39)
hence by Gronwallrsquos lemma
100381710038171003817100381712058810038171003817100381710038171119901
le 119862ℎ(1199062119901 + int
119905
0
1199062119901119889119904) (40)
The derivation of the error estimate in 119871119901 is similar to the casewhen 119901 = 2
4 Error Estimates forSemidiscrete Approximations
We split the error 119890(119905) = 119906(119905) minus 119906ℎ(119905) as follows
119890 (119905) = (119906 (119905) minus 119881ℎ119906 (119905)) + (119881
ℎ119906 (119905) minus 119906
ℎ(119905)) = 120588 + 120579 (41)
It is easy to see that 120579 = 119881ℎ119906(119905) minus 119906
ℎ(119905) isin 119878
ℎsatisfies an
error equation of the form
(120579119905 119868
lowast
ℎVℎ) + 119860 (119905 120579 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎVℎ) 119889119904
= minus (120588119905 119868
lowast
ℎVℎ) V
ℎisin 119878
ℎ
(42)
Since the estimates of 120588 are already known it is enoughto have estimates for 120579
We will prove a sequence of lemmas which lead to thefollowing result
Lemma8 There is a positive constant119862 independent of ℎ suchthat
|||120579 (119905)||| le 119862(|||120579 (0)|||2+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817 119889119904) (43)
Proof Since 120579 isin 119878ℎwe may take V
ℎ= 120579 in (42) to obtain
1
2
119889
119889119905|||120579 (119905)|||
2+ 119888120579
2
1le
10038171003817100381710038171205881199051003817100381710038171003817 120579 + 119862int
119905
0
12057911198891199041205791
le1003817100381710038171003817120588119905
1003817100381710038171003817 120579 +1
2119888120579
2
1+ 119862int
119905
0
1205792
1119889119904
(44)
and hence by integration and Lemma 1 we have
||120579 (119905)||2+ int
119905
0
1205792
1119889119904
le 119862(|||120579 (0)|||2+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817 120579 119889119904 + int
119905
0
int
119904
0
120579 (120591)2
1119889120591119889119904)
(45)
Gronwallrsquos lemma now implies the following
|||120579 (119905)|||2+ int
119905
0
1205792
1119889119904 le 119862(|||120579 (0)|||
2+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817 120579 119889119904)
le 119862|||120579 (0)|||2+1
2sup119904le119905
120579 (119904)2
+ (int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817 119889119904)
2
(46)
Since this holds for all isin 119869 we may conclude that
||120579 (119905)|| le 119862(|||120579 (0)||| + int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817 119889119904) (47)
Journal of Mathematics 7
Remark 9 If the initial value was chosen so that 1199060ℎminus 119906
0 le
119862ℎ2119906
02 then 120579(0) le 119906
0ℎminus119906
0+119881
ℎ1199060minus119906
0 le 119862ℎ
2119906
02
One can derive
|||120579 (119905)||| le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (48)
Lemma 10 There is a positive constant 119862 independent of ℎsuch that
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
119889119904 + 1205792
1le 119862(120579 (0)
2
1+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
2
119889119904) (49)
Proof Set Vℎ= 120579
119905in (42) to get
10038171003817100381710038171205791199051003817100381710038171003817
2
+1
2
119889
119889119905119860 (119905 120579 119868
lowast
ℎ120579)
= minus (120588119905 119868
lowast
ℎ120579119905) minus int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579119905(119905)) 119889119904
+1
2119860
119905(119905 120579 119868
lowast
ℎ120579)
+1
2[119860 (119905 120579
119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)]
le1
2
10038171003817100381710038171205881199051003817100381710038171003817
2
+1
2
1003816100381610038161003816
1003816100381610038161003816
10038161003816100381610038161205791199051003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816
2
+ 119860119905(119905 120579 119868
lowast
ℎ120579)
+1
2[119860 (119905 120579
119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)]
minus119889
119889119905int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579 (119905)) 119889119904
+ 119861 (119905 119905 120579 (119905) 119868lowast
ℎ120579 (119905)) + int
119905
0
119861119905(119905 119904 120579 (119904) 119868
lowast
ℎ120579 (119905)) 119889119904
(50)
Then
10038171003817100381710038171205791199051003817100381710038171003817
2
+119889
119889119905119860 (119905 120579 119868
lowast
ℎ120579)
le1003817100381710038171003817120588119905
1003817100381710038171003817
2
minus119889
119889119905int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579) 119889119904
+ 119862(1205792
1+ int
119905
0
120579 (119904)2
1119889119904)
+1
2[119860 (119905 120579
119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)]
(51)
In addition recall that
119860 (119905 119906ℎ 119868
lowast
ℎVℎ) minus 119860 (119905 V
ℎ 119868
lowast
ℎ119906ℎ) le 119862ℎ
1003817100381710038171003817119906ℎ
10038171003817100381710038171
1003817100381710038171003817Vℎ10038171003817100381710038171
forall119906ℎ V
ℎisin 119878
ℎ
(52)
then applying an inverse inequality and using kickbackargument we obtain
[119860 (119905 120579119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)] le 119862ℎ
100381710038171003817100381712057911990510038171003817100381710038171
1205791 le 1198621003817100381710038171003817120579119905
1003817100381710038171003817 1205791
le 1205761003817100381710038171003817120579119905
1003817100381710038171003817
2
+ 1198621205792
1
(53)
Combining these estimates we derive
10038171003817100381710038171205791199051003817100381710038171003817
2
+119889
119889119905119860 (119905 120579 119868
lowast
ℎ120579)
le1003817100381710038171003817120588119905
1003817100381710038171003817
2
minus119889
119889119905int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579) 119889119904
+ 119862(1205792
1+ int
119905
0
120579 (119904)2
1119889119904)
(54)
So after integration in time and using the weak coercivity of119860(119905 120579 119868
lowast
ℎ120579) we get
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
119889119904 + 1198880120579
2
1
le 1198880120579 (0)
2
1+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
2
119889119904
+ int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579) 119889119904 + 119862int
119905
0
120579 (119904)2
1119889119904
le 1198880120579 (0)
2
1+119888
2120579
2
1+ 119862(int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
2
+ 120579 (119904)2
1119889119904)
(55)
and by Gronwallrsquos lemma
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
119889119904 + 1198881205792
1le 119862(120579 (0)
2
1+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
2
119889119904) (56)
Remark 11 If 120579(0) = 0 then
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
119889119904 + 1198881205792
1le 119862ℎ
2(int
119905
0
1003817100381710038171003817119906119905
1003817100381710038171003817
2
2119889119904) (57)
Theorem 12 (error estimates in 1198712 and1198671-norms) Let 119906 119906
ℎ
be the solutions of (2) and (11) respectively Assume that 119906 119906119905isin
119871infin(119867
1
0cap 119867
2)
(a) Let 1199060ℎ
be chosen so that 1199060ℎ
minus 1199060 le 119862ℎ
2119906
02
Then for 119879 gt 0 fixed there is a constant 119862 = 119862(119879)
independent of ℎ such that for all 0 lt 119905 lt 119879
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905)
1003817100381710038171003817 le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (58)
(b) Let 1199060ℎ
be chosen so that 1199060ℎminus 119906
01
le 119862ℎ11990602
Then for 119879 gt 0 fixed there is a constant 119862 = 119862(119879)
independent of ℎ such that for all 0 lt 119905 lt 119879
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905))
10038171003817100381710038171le 119862ℎ(
10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (59)
We now prove error estimates for FVE approximations in119871119901 and119882
1119901-norms
8 Journal of Mathematics
Theorem 13 (error estimates in 119871119901 and 119882
1119901-norms) Let119906 119906
ℎbe the solutions of (2) and (11) respectively and 119906
0ℎ=
119881ℎ1199060 Assume that 119906 119906
119905isin 119871
infin(119867
1
0cap 119882
2119901) For ℎ sufficiently
small we have
1003817100381710038171003817119906 minus 119906ℎ
10038171003817100381710038170119901le 119862ℎ
2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
1003817100381710038171003817119906 minus 119906ℎ
10038171003817100381710038171119901le 119862ℎ(
10038171003817100381710038171199060
10038171003817100381710038172+ 1199062119901 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
(60)
Proof If 2 le 119901 lt infin by the following Sobolev embeddinginequality
1205790119901 le 1198621205791 (61)
then the first desired estimate follows from Lemmas 7 and 10Given 120593 isin Cinfin
0(Ω) find 120595 isin 119867
1
0(Ω) such that
119860(119905)lowast120595 = minus120593
119909 in Ω
120595 = 0 on 120597Ω
100381710038171003817100381712059510038171003817100381710038171119902
le100381710038171003817100381712059310038171003817100381710038170119902
(62)
We have
((119906 minus 119906ℎ)119909 120593) = 119860 (119905 119906 minus 119906
ℎ 120595) = 119860 (119905 119906 minus 119906
ℎ 120595 minus 119877
ℎ120595)
+ 119860 (119905 119906 minus 119906ℎ 119877
ℎ120595 minus 119868
lowast
ℎ119877ℎ120595)
minus int
119905
0
119861 (119905 119904 (119906 minus 119906ℎ) (119904) 119868
lowast
ℎ119877ℎ120595) 119889119904
minus ((119906 minus 119906ℎ)119905 119868
lowast
ℎ119877ℎ120595)
= 1198681+ 119868
2+ 119868
3+ 119868
4
100381610038161003816100381611986811003816100381610038161003816 le
1003816100381610038161003816119860 (119905 119906 minus 119877ℎ119906 120595)
1003816100381610038161003816 le 1198621003817100381710038171003817119906 minus 119877
ℎ11990610038171003817100381710038171119901
100381710038171003817100381712059510038171003817100381710038171119902
le 119862ℎ11990621199011003817100381710038171003817120595
10038171003817100381710038171119902
(63)
By Lemma 4
100381610038161003816100381611986821003816100381610038161003816 le 119860 (119905 119906 minus 119906
ℎ 119877
ℎ120595 minus 119868
lowast
ℎ119877ℎ120595)
le 119862ℎ (1003816100381610038161003816119906 minus 119906
ℎ
10038161003816100381610038161119901+ |119906|2119901)
100381710038171003817100381712059510038171003817100381710038171119902
100381610038161003816100381611986831003816100381610038161003816 le int
119905
0
1003817100381710038171003817119906 minus 119906ℎ
100381710038171003817100381711199011198891199041003817100381710038171003817120595
10038171003817100381710038171119902
100381610038161003816100381611986841003816100381610038161003816 le (
1003817100381710038171003817119906 minus 119906ℎ
1003817100381710038171003817)1003817100381710038171003817120595
1003817100381710038171003817 le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
100381710038171003817100381712059510038171003817100381710038171119902
(64)
where we have used the fact 120595 le 1205951119903 119903 gt 1 Combining
these estimates we get
1003816100381610038161003816((119906 minus 119906ℎ)119909 120593)
1003816100381610038161003816 le 119862ℎ(10038171003817100381710038171199060
10038171003817100381710038172+ 1199062119901 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
100381710038171003817100381712059510038171003817100381710038171119902
1003817100381710038171003817(119906 minus 119906ℎ)119909
10038171003817100381710038170119901= sup
((119906 minus 119906ℎ)119909 120593)
100381710038171003817100381712059310038171003817100381710038170119902
le 119862ℎ1003816100381610038161003816119906 minus 119906
ℎ
10038161003816100381610038161119901
+ 119862ℎ(10038171003817100381710038171199060
10038171003817100381710038172+ 1199062119901 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
(65)
Hence using the Poincare inequality we have for ℎ sufficientlysmall
1003817100381710038171003817119906 minus 119906ℎ
10038171003817100381710038171119901le 119862ℎ(
10038171003817100381710038171199060
10038171003817100381710038172+ 1199062119901 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (66)
We compare the relationship between covolume solutionand the Galerkin finite element solution
Corollary 14 Let ℎbe the finite element solution to (2) that
is
(ℎ119905 V
ℎ) + 119860 (119905
ℎ V
ℎ)
+ int
119905
0
119861 (119905 119904 ℎ(119904) V
ℎ) 119889119904 = (119891 V
ℎ) V
ℎisin 119878
ℎ
ℎ(0) = 119877
ℎ1199060
(67)
For ℎ sufficiently small we have
1003817100381710038171003817(ℎminus 119906
ℎ)10038171003817100381710038171119901
le 119862(
ℎ1003817100381710038171003817119906 minus 119906
ℎ
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus 119906
ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817
+int
119905
0
(1003817100381710038171003817(119906 minus 119906
ℎ) (119904)
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus
ℎ) (119904)
10038171003817100381710038171119901) 119889119904
)
le 119862 (119906) ℎ
(68)
Proof By (2) and (67)
((ℎminus 119906)
119905 V
ℎ) + 119860 (119905
ℎminus 119906 V
ℎ)
+ int
119905
0
119861 (119905 119904 (ℎminus 119906) (119904) V
ℎ) 119889119904 = 0 V
ℎisin 119878
ℎ
(69)
Consider the following auxiliary problem For any such 120593 let120595 be the solution of the following
119860(119905)lowast120595 = minus120593
119909 in Ω
120595 = 0 on 120597Ω
(70)
Journal of Mathematics 9
with1003817100381710038171003817120595
10038171003817100381710038171119902le100381710038171003817100381712059310038171003817100381710038170119902
((ℎminus 119906
ℎ)119909 120593)
= 119860 (119905 ℎminus 119906
ℎ 120595)
= 119860 (119905 ℎminus 119906
ℎ 120595 minus 119877
ℎ120595) + 119860 (119905 119906 minus 119906
ℎ 119877
ℎ120595)
minus 119860 (119905 119906 minus 119906ℎ 119868
lowast
ℎ119877ℎ120595) minus ((119906 minus 119906
ℎ)119905 119868
lowast
ℎ119877ℎ120595)
minus int
119905
0
119861 (119905 119904 (119906 minus 119906ℎ) (119904) 119868
lowast
ℎ119877ℎ120595) 119889119904
+ 119860 (119905 ℎminus 119906 119877
ℎ120595)
= [119860 (119905 119906 minus 119906ℎ 119877
ℎ120595) minus 119860 (119905 119906 minus 119906
ℎ 119868
lowast
ℎ119877ℎ120595)]
minus ((119906 minus 119906ℎ)119905 119868
lowast
ℎ119877ℎ120595) minus ((
ℎminus 119906)
119905 119877
ℎ120595)
minus int
119905
0
119861 (119905 119904 (119906 minus 119906ℎ) (119904) 119868
lowast
ℎ119877ℎ120595) 119889119904
minus int
119905
0
119861 (119905 119904 (ℎminus 119906) (119904) 119877
ℎ120595) 119889119904
= 1198681+ 119868
2+ 119868
3
(71)
On the other hand10038161003816100381610038161198681
1003816100381610038161003816 le 119862ℎ1003817100381710038171003817119906 minus 119906
ℎ
10038171003817100381710038171119901
100381710038171003817100381712059510038171003817100381710038171119902
100381610038161003816100381611986821003816100381610038161003816 le 119862 (
1003817100381710038171003817(119906 minus 119906ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817)1003817100381710038171003817120595
1003817100381710038171003817
le 119862 (1003817100381710038171003817(119906 minus 119906
ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817)1003817100381710038171003817120595
10038171003817100381710038171119902
(72)
where we have used the fact 120595 le 1205951119903 119903 gt 1
100381610038161003816100381611986831003816100381610038161003816 le int
119905
0
(1003817100381710038171003817(119906 minus 119906
ℎ) (119904)
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus
ℎ) (119904)
10038171003817100381710038171119901) 119889119904
100381710038171003817100381712059510038171003817100381710038171119902
1003817100381710038171003817(ℎminus 119906
ℎ)119909
10038171003817100381710038170119901
= sup120593isinCinfin0
((ℎminus 119906
ℎ)119909 120593)
100381710038171003817100381712059310038171003817100381710038170119902
le 119862(
ℎ1003817100381710038171003817119906 minus 119906
ℎ
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus 119906
ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817
+int
119905
0
(1003817100381710038171003817(119906 minus 119906
ℎ) (119904)
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus
ℎ) (119904)
10038171003817100381710038171119901) 119889119904
)
(73)
We deduce the result from the known finite element esti-mates
Remark 15 In order to estimate (119906 minus 119906ℎ)119905 by differentiating
(42) with respect to 119905 we obtain
(120579119905119905 119868
lowast
ℎVℎ) + 119860 (119905 120579
119905 119868
lowast
ℎVℎ) + 119860
119905(119905 120579
119905 119868
lowast
ℎVℎ)
+ 119861 (119905 119905 120579 119868lowast
ℎVℎ) + int
119905
0
119861119905(119905 119904 120579 (119904) 119868
lowast
ℎVℎ) 119889119904
= minus (120588119905119905 119868
lowast
ℎVℎ)
(74)
Setting Vℎ= 120579
119905 we obtain
1
2
119889
119889119905
1003816100381610038161003816
1003816100381610038161003816
10038161003816100381610038161205791199051003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816
2
+ 1198881003817100381710038171003817120579119905
1003817100381710038171003817
2
1le1003817100381710038171003817120588119905119905
1003817100381710038171003817
10038171003817100381710038171205791199051003817100381710038171003817
+1
21198881003817100381710038171003817120579119905
1003817100381710038171003817
2
1+ 119862120579
2
1+ int
119905
0
1205792
1119889119904
le1003817100381710038171003817120588119905119905
1003817100381710038171003817
10038171003817100381710038171205791199051003817100381710038171003817 +
1
21198881003817100381710038171003817120579119905
1003817100381710038171003817
2
1+ 119862int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
1119889119904
(75)
Using kickback argument integrating and applying Gron-wallrsquos lemma we deduce
10038171003817100381710038171205791199051003817100381710038171003817 le 119862(
1003817100381710038171003817120579119905 (0)1003817100381710038171003817 + int
119905
0
100381710038171003817100381712058811990511990510038171003817100381710038171119889119904)
le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+10038171003817100381710038171199061
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904)
(76)
5 The Lumped Mass Finite VolumeElement Method
In this section we restrict our study to the 2D case A simpleway to define the lumped mass scheme [21] is to replace themass matrix 119872
ℎin (14) by the diagonal matrix 119872
ℎobtained
by taking for its diagonal elements the numbers 119872ℎ119894119894
=
sum119873ℎ
119895=1119872
ℎ119894119895or by lumping all masses in one row into the
diagonal entryThismakes the inversion of thematrix in frontof1205721015840
(119905) a trivialityWewill therefore study thematrix problem
119872ℎ1205721015840(119905) + 119860
ℎ(119905) 120572 (119905) + int
119905
0
119861ℎ(119905 119904) 120572 (119904) 119889119904 = 119865
ℎ(119905) (77)
We know that the lumped mass method defined by (77)above is equivalent to
(119868lowast
ℎ119906ℎ119905 119868
lowast
ℎVℎ) + 119860 (119905 119906
ℎ 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 119906ℎ(119904) 119868
lowast
ℎVℎ) 119889119904
= (119891 119868lowast
ℎVℎ) V
ℎisin 119878
ℎ
(78)
Our alternative interpretation of this procedure will beto think of (77) as being obtained by evaluating the firstterm in (78) by numerical quadrature Let 119870 be a triangle ofthe triangulation 119879
ℎ let 119909
119895 119895 = 1 2 3 be its vertices and
consider the quadrature formula
119876119870ℎ
(119891) =1
3area119870
3
sum
119895=1
119891 (119909119895) ≃ int
119870
119891119889119909 (79)
We may then define the associated bilinear form in 119878ℎtimes
119878lowast
ℎ using the quadrature scheme by the following
(Vℎ 120578
ℎ)ℎ= sum
119870isin119879ℎ
119876119870ℎ
(Vℎ120578ℎ) = sum
119909119894isin119873119886
ℎ
Vℎ(119909
119894) 120578
ℎ(119909
119894)10038161003816100381610038161003816119881119909119894
10038161003816100381610038161003816
forallVℎisin 119878
ℎ 120578
ℎisin 119878
lowast
ℎ
(80)
10 Journal of Mathematics
We note that Vℎ2
ℎ= (V
ℎ 119868
lowast
ℎVℎ)ℎis a norm in 119878
ℎwhich is
equivalent to the 1198712-norm uniformly in ℎ that is there existtwo positive constants 119862
1and 119862
2such that for all V
ℎisin 119878
ℎ we
have
1198620
1003817100381710038171003817Vℎ1003817100381710038171003817 le
1003817100381710038171003817Vℎ1003817100381710038171003817ℎ
le 1198621
1003817100381710038171003817Vℎ1003817100381710038171003817 forallV
ℎisin 119878
ℎ (81)
We note that the aforementioned definition (Vℎ 120578
ℎ)ℎmay
be used also for 120578ℎisin 119878
ℎand that (V
ℎ 119908
ℎ)ℎ= (V
ℎ 119868
lowast
ℎ119908
ℎ)ℎfor
Vℎ 119908
ℎisin 119878
ℎ
The lumpedmass method defined by (78) is equivalent to
(119906ℎ119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 119906
ℎ 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 119906ℎ(119904) 119868
lowast
ℎVℎ) 119889119904
= (119891 119868lowast
ℎVℎ) V
ℎisin 119878
ℎ
(82)
We introduce the quadrature error
120576ℎ(V
ℎ 119908
ℎ) = (V
ℎ 119908
ℎ)ℎminus (V
ℎ 119908
ℎ) (83)
Lemma 16 (see [21]) Let Vℎ 119908
ℎisin 119878
ℎ Then
1003816100381610038161003816120576ℎ (Vℎ 119908ℎ)1003816100381610038161003816 le 119862ℎ
2 1003817100381710038171003817nablaVℎ1003817100381710038171003817
1003817100381710038171003817nabla119908ℎ
1003817100381710038171003817 (84)
Theorem 17 Let 119906ℎand 119906 be the solutions of (82) and (2)
respectively and assume 119906ℎ(0) = 119877
ℎ1199060 Then we have for the
error in the lumped mass semidiscrete method for 119905 ge 0 thefollowing
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905)
1003817100381710038171003817 le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ 1199062 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (85)
Proof In order to estimate 120579 we write
(120579119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 120579 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎVℎ) 119889119904
= (119906ℎ119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 119906
ℎ 119868
lowast
ℎVℎ)
+ int
119905
0
119861 (119905 119904 119906ℎ(119904) 119868
lowast
ℎVℎ) 119889119904
minus ((119881ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus 119860 (119905 119881
ℎ119906 119868
lowast
ℎVℎ)
minus int
119905
0
119861 (119905 119904 119881ℎ119906 (119904) 119868
lowast
ℎVℎ) 119889119904
= (119891 119868lowast
ℎVℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus 119860 (119905 119906 119868
lowast
ℎVℎ)
minus int
119905
0
119861 (119905 119904 119906 (119904) 119868lowast
ℎVℎ)
= (119906119905 119868
lowast
ℎVℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)ℎ
= minus (120588119905 119868
lowast
ℎVℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)ℎ+ ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
(86)
We rewrite
((119881ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
= ((119881ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus ((119881
ℎ119906)
119905 V
ℎ)
+ ((119881ℎ119906)
119905 V
ℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
= 120576ℎ((119881
ℎ119906)
119905 V
ℎ) + ((119881
ℎ119906)
119905 V
ℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
(120579119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 120579 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎVℎ) 119889119904
= minus (120588119905 119868
lowast
ℎVℎ) + 120576
ℎ((119881
ℎ119906)
119905 V
ℎ)
+ ((119881ℎ119906)
119905 V
ℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
(87)
Setting Vℎ= 120579 in (87) we obtain
1
2
119889
119889119905120579
2
ℎ+ 119888
01205792
1
le1003817100381710038171003817120588119905
1003817100381710038171003817 120579 +1
21198880120579
2
1+ 119862int
119905
0
1205792
1119889119904
+ 120576ℎ((119881
ℎ119906)
119905 120579) + ((119881
ℎ119906)
119905 120579) minus ((119881
ℎ119906)
119905 119868
lowast
ℎ120579)
(88)
Using Lemma 16 and the inverse estimate we get1003816100381610038161003816120576ℎ (119881ℎ
119906119905 120579)
1003816100381610038161003816 le 119862ℎ2 1003817100381710038171003817nabla(119881ℎ
119906)119905
1003817100381710038171003817 nabla120579
le 119862ℎ2 1003817100381710038171003817nabla119906119905
1003817100381710038171003817 nabla120579
le 119862ℎ1003817100381710038171003817nabla119906119905
1003817100381710038171003817 120579
(89)
we have1003816100381610038161003816((119881ℎ
119906)119905 120579) minus ((119881
ℎ119906)
119905 119868
lowast
ℎ120579)1003816100381610038161003816 le 119862ℎ
1003817100381710038171003817nabla119906119905
1003817100381710038171003817 120579 (90)
Using Youngrsquos inequality and Gronwallrsquos lemma to eliminate120579
1on the right-hand side and using integration in 119905 we get
the result
1
2
119889
119889119905120579
2
ℎ+ 119888
0 120579 le1003817100381710038171003817120588119905
1003817100381710038171003817 120579 + 119862ℎ1003817100381710038171003817nabla119906119905
1003817100381710038171003817 120579 (91)
Using Youngrsquos inequality to eliminate 120579 on the right handside it becomes
Using integration in 119905 we get the result
We will now show that the 1198671-norm error bound of
theorem remains valid for the lumped mass method (82)
Theorem 18 Let 119906ℎand 119906 be the solutions of (82) and (2)
respectively and assume
119906ℎ(0) = 119877
ℎ1199060
10038171003817100381710038171199061ℎ(0) minus 119906
1
1003817100381710038171003817 le 119862ℎ210038171003817100381710038171199061
10038171003817100381710038172 (92)
Then we have for the error in the lumped mass semidiscretemethod for 119905 ge 0 the following
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905)
10038171003817100381710038171le 119862ℎ
2(10038171003817100381710038171199060
10038171003817100381710038172+10038171003817100381710038171199061
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904)
(93)
Journal of Mathematics 11
Proof Setting Vℎ= 120579
119905in (87) we obtain
10038171003817100381710038171205791199051003817100381710038171003817
2
ℎ+1
2
119889
119889119905119860 (119905 120579 119868
lowast
ℎ120579)
=1
2119860
119905(119905 120579 119868
lowast
ℎ120579) +
1
2[119860 (119905 120579
119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)]
119861 (119905 119905 120579 (119905) 119868lowast
ℎ120579 (119905)) + int
119905
0
119861119905(119905 119904 120579 (119904) 119868
lowast
ℎ120579 (119905)) 119889119904
minus119889
119889119905int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579 (119905)) 119889119904 minus (120588
119905 119868
lowast
ℎ120579119905)
minus 120576ℎ((119881
ℎ119906)
119905 120579
119905) + ((119881
ℎ119906)
119905 120579) minus ((119881
ℎ119906)
119905 119868
lowast
ℎ120579)
(94)
It follows thus that using integration in 119905 and Gronwallrsquoslemma we have
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
ℎ+ 120579
2
1le 119862nabla120579 (0)
2+ 119862int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
10038171003817100381710038171205791199051003817100381710038171003817 119889119904
+ 119862ℎ2int
119905
0
1003817100381710038171003817119906119905
1003817100381710038171003817
2
1119889119904
(95)
6 Full Discretization
Let 120597119880119899= (119880
119899minus119880
119899minus1)119896 be the backward difference quotient
of 119880119899 assume that 119860ℎ
= 119875ℎ119860 is a discrete analogue of 119860
(similarly 119861ℎ
= 119875ℎ119861) where 119875
ℎ 119871
2(Ω) rarr 119878
lowast
ℎthe 119871
2
projection is defined by
(119875ℎV 119868lowast
ℎVℎ) = (V 119868lowast
ℎVℎ) V isin 119871
2(Ω) V
ℎisin 119878
ℎ (96)
In order to define fully discrete approximation of (11) wediscretize the time by taking 119905
119899= 119899119896 119896 gt 0 119899 = 1 2 and
use the numerical quadrature
int
119905119899minus12
0
119892 (119904) 119889119904 asymp
119899
sum
119896=1
120596119899119896119892 (119905
119896minus12) 119905
119899minus12= (119899 minus
1
2) 119896
(97)
Here 120596119899119896 are the integrationweights andwe assume that
the following error estimate is valid
119902119899(119892) = int
119905119899minus12
0
119892 (119904) 119889119904minus
119899
sum
119896=1
120596119899119896119892 (119905
119896minus12)
le 1198621198962int
119905119899
0
(10038161003816100381610038161003816119892101584010038161003816100381610038161003816+100381610038161003816100381610038161198921015840101584010038161003816100381610038161003816) 119889119904
(98)
Now define our complete discrete FVE approximation of(11) by the following find 119880
119899isin 119878
ℎfor 119899 = 1 2 such that
for all Vℎisin 119878
ℎ
(120597119880119899 119868
lowast
ℎVℎ) + 119860 (119905
119899minus12 119880
119899minus12 119868
lowast
ℎVℎ)
+
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12 119880
119896minus12 119868
lowast
ℎVℎ)
= (119891119899minus12
119868lowast
ℎVℎ)
1198800 in 119878
ℎ
(99)
where 119880119899minus12= (119880
119899+ 119880
119899minus1)2
Theorem 19 Let 119906(119905) and 119880119899 be the solutions of problem (2)
and its complete discrete scheme (99) respectively Then forany 119879 gt 0 there exists a positive constant 119862 = 119862(119879) gt 0independent of ℎ such that for 0 lt 119905
119899le 119879
1003817100381710038171003817119906 (119905119899) minus 1198801198991003817100381710038171003817
le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905119899
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
+ 1198621198962(int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905119905
1003817100381710038171003817) 119889119904)
(100)
Proof Let us split the error into two parts 119906(119905119899) minus 119880
119899= 120588
119899+
120579119899 where 120588
119899= 119906(119905
119899)minus119881
ℎ119906(119905
119899) and 120579119899 = 119881
ℎ119906(119905
119899)minus119880
119899 and let119882 = 119881
ℎ119906(119905) isin 119878
ℎbe the Ritz-Volterra projection of 119906 Then
from (2) and (99) we have for all Vℎisin 119878
ℎthe following
(120597120579119899 119868
lowast
ℎVℎ) + 119860 (119905
119899minus12 120579
119899minus12 119868
lowast
ℎVℎ)
+
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12 120579
119896minus12 119868
lowast
ℎVℎ)
= minus (119903119899 119868
lowast
ℎVℎ) forallV
ℎisin 119878
ℎ
(101)
where
119903119899= 119903
1
119899+ 119903
2
119899+ 119903
3
119899+ 119903
4
119899
1199031
119899= 120597120588
119899
1199032
119899= 120597119906 (119905
119899) minus 119906
119905(119905
119899minus12)
1199033
119899= 119860(119905
119899minus12(119906 (119905
119899) + 119906 (119905
119899minus1))
2minus 119906 (119905
119899minus12))
1199034
119899= 119902
119899(119861
ℎ119882)
=
119899
sum
119896=1
120596119899119896119861ℎ(119905
119899minus12 119905
119896minus12119882
119896minus12 119868
lowast
ℎVℎ)
minus int
119905119899minus12
0
119861 (119905119899 119904119882 (119904) 119868
lowast
ℎVℎ) 119889119904
(102)
In fact by Taylor expansion
119906119899+1
= 119906119899+ 119896119906
1015840(119905
119899) + int
119905119899+1
119905119899
11990610158401015840(119904) (119905
119899+1minus 119904) 119889119904
= 119906119899+ 119896119906
1015840(119905
119899) +
1198962
211990610158401015840(119905
119899) +
1198963
6119906(3)
(119905119899)
+1
6int
119905119899+1
119905119899
119906(4)
(119904) (119905119899+1
minus 119904)3
119889119904
(103)
12 Journal of Mathematics
we have100381710038171003817100381710038171199031
119899
10038171003817100381710038171003817=
10038171003817100381710038171003817120597120588
11989910038171003817100381710038171003817le
1
119896int
119905119899
119905119899minus1
10038171003817100381710038171205881199051003817100381710038171003817 119889119904 le 119862
ℎ2
119896int
119905119899
119905119899minus1
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
100381710038171003817100381710038171199032
119899
10038171003817100381710038171003817=
10038171003817100381710038171003817120597119906 (119905
119899) minus 119906
119905(119905
119899minus12)10038171003817100381710038171003817
=1
119896
100381710038171003817100381710038171003817100381710038171003817
int
119905119899
119905119899minus1
(119906119905(119904) minus 119906
119905(119905
119899minus12)) 119889119904
100381710038171003817100381710038171003817100381710038171003817
le 119862119896int
119905119899
119905119899minus1
10038171003817100381710038171003817119906(3)
(119904)10038171003817100381710038171003817119889119904
100381710038171003817100381710038171199033
119899
10038171003817100381710038171003817=
100381710038171003817100381710038171003817100381710038171003817
119860(119905119899minus12
119906 (119905
119899) + 119906 (119905
119899minus1)
2minus 119906 (119905
119899minus12) 119868
lowast
ℎVℎ)
100381710038171003817100381710038171003817100381710038171003817
le 119862119896int
119905119899
119905119899minus1
1003817100381710038171003817119860119906119905119905(119904)
1003817100381710038171003817 119889119904 le 119862119896int
119905119899
119905119899minus1
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
(104)
In addition the quadrature error satisfies100381710038171003817100381710038171199034
119899
10038171003817100381710038171003817= 119902
119899minus12(119861
ℎ119882)
=
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12119882
119896minus12 119868
lowast
ℎVℎ)
minus int
119905119899minus12
0
119861 (119905119899 119904119882 (119904) 119868
lowast
ℎVℎ) 119889119904
le 1198621198962int
119905119899
0
1003817100381710038171003817(119861ℎ119882)
119904119904
1003817100381710038171003817 119889119904
le 1198621198962int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172) 119889119904
119896
119873
sum
119899=1
10038171003817100381710038171199031198991003817100381710038171003817 le 119862ℎ
2int
119905119899
0
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
+ 1198621198962int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172+10038171003817100381710038171003817119906(3)10038171003817100381710038171003817
) 119889119904
(105)
Taking Vℎ= 120579
119899minus12 in (101) and noting that (120597120579119899 119868lowastℎ120579119899minus12
) =
(12)120597|||120579119899|||
2 there is1003816100381610038161003816
1003816100381610038161003816
10038161003816100381610038161205791198991003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816
2
minus10038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus110038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
+ 211989611988810038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus1210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
1
le 1198621198962
119899
sum
119896=1
10038171003817100381710038171003817120579119896minus12100381710038171003817100381710038171
10038171003817100381710038171003817120579119899minus12100381710038171003817100381710038171
+ 1198621198961003817100381710038171003817119903119899
1003817100381710038171003817
10038171003817100381710038171003817120579119899minus1210038171003817100381710038171003817
le11989611988810038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus1210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
1+ 119862119896
2
119899
sum
119896=1
10038171003817100381710038171003817120579119896minus1210038171003817100381710038171003817
2
1+ 119862119896
10038171003817100381710038171199031198991003817100381710038171003817
10038171003817100381710038171003817120579119899minus1210038171003817100381710038171003817
(106)
Summing from 119899 = 1 to 119873 and then after cancelling thecommon factor and using Gronwallrsquos lemma we obtain
10038161003816100381610038161003816
10038161003816100381610038161003816
1003816100381610038161003816100381612057911987310038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
le 11986210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579010038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
+ 119862119896
119873
sum
119896=1
10038171003817100381710038171199031198991003817100381710038171003817 (
1003817100381710038171003817100381712057911989610038171003817100381710038171003817
+10038171003817100381710038171003817120579119896minus1210038171003817100381710038171003817
) (107)
and then
10038161003816100381610038161003816
10038161003816100381610038161003816
1003816100381610038161003816100381612057911987310038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816le 119862
10038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579010038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816+ 119862119896
119873
sum
119899=1
10038171003817100381710038171199031198991003817100381710038171003817
(108)
the theorem follows from the estimates of 120588119899 and 119903119899
References
[1] Z Q Cai ldquoOn the finite volume element methodrdquo NumerischeMathematik vol 58 no 7 pp 713ndash735 1991
[2] S H Chou and D Y Kwak ldquoAnalysis and convergence of aMAC-like scheme for the generalized Stokes problemrdquo Numer-ical Methods for Partial Differential Equations vol 13 no 2 pp147ndash162 1997
[3] P Chatzipantelidis ldquoA finite volume method based on theCrouzeix-Raviart element for elliptic PDErsquos in two dimensionsrdquoNumerische Mathematik vol 82 no 3 pp 409ndash432 1999
[4] P Chatzipantelidis ldquoFinite volumemethods for elliptic PDErsquos anew approachrdquo Mathematical Modelling and Numerical Analy-sis vol 36 no 2 pp 307ndash324 2002
[5] P Chatzipantelidis R D Lazarov and V Thomee ldquoErrorestimates for a finite volume element method for parabolicequations in convex polygonal domainsrdquoNumericalMethods forPartial Differential Equations vol 20 no 5 pp 650ndash674 2004
[6] R E Ewing R D Lazarov and Y Lin ldquoFinite volume elementapproximations of nonlocal in time one-dimensional flows inporous mediardquo Computing vol 64 no 2 pp 157ndash182 2000
[7] R Ewing R Lazarov and Y Lin ldquoFinite volume elementapproximations of nonlocal reactive flows in porous mediardquoNumericalMethods for Partial Differential Equations vol 16 no3 pp 285ndash311 2000
[8] R E Ewing T Lin andY Lin ldquoOn the accuracy of the finite vol-ume element method based on piecewise linear polynomialsrdquoSIAM Journal on Numerical Analysis vol 39 no 6 pp 1865ndash1888 2002
[9] R K Sinha and J Geiser ldquoError estimates for finite volumeelement methods for convection-diffusion-reaction equationsrdquoApplied Numerical Mathematics vol 57 no 1 pp 59ndash72 2007
[10] S H Chou ldquoAnalysis and convergence of a covolume methodfor the generalized Stokes problemrdquo Mathematics of Computa-tion vol 66 no 217 pp 85ndash104 1997
[11] M Berggren ldquoA vertex-centered dual discontinuous Galerkinmethodrdquo Journal of Computational and Applied Mathematicsvol 192 no 1 pp 175ndash181 2006
[12] S H Chou and D Y Kwak ldquoMultigrid algorithms for a vertex-centered covolume method for elliptic problemsrdquo NumerischeMathematik vol 90 no 3 pp 441ndash458 2002
[13] R Eymard T Gallouet and R Herbin Finite Volume MethodsHandbook of Numerical Analysis North-Holland AmsterdamThe Netherlands 2000
[14] V R Voller Basic Control Volume Finite Element Methods forFluids and Solids World Scientific Publishing 2009
[15] J Huang and S Xi ldquoOn the finite volume element method forgeneral self-adjoint elliptic problemsrdquo SIAM Journal on Numer-ical Analysis vol 35 no 5 pp 1762ndash1774 1998
[16] X Ma S Shu and A Zhou ldquoSymmetric finite volume discreti-zations for parabolic problemsrdquo Computer Methods in AppliedMechanics and Engineering vol 192 no 39-40 pp 4467ndash44852003
[17] R D Lazarov and S Z Tomov ldquoAdaptive finite volume elementmethod for convection-diffusion-reaction problems in 3-Drdquo inScientific Computing and Applications vol 7 of Advances inComputation Theory and Practice pp 91ndash106 Nova SciencePublishers Huntington NY USA 2001
[18] I DMishevFinite volume and finite volume elementmethods fornon-symmetric problems [PhD thesis] Texas AampM University1997 Technical Report ISC-96-04-MATH
Journal of Mathematics 13
[19] C Chen and T Shih Finite Element Methods for Integrodifferen-tial Equations World Scientific Publishing Singapore 1998
[20] Y P Lin V Thomee and L B Wahlbin ldquoRitz-Volterra pro-jections to finite-element spaces and applications to integrod-ifferential and related equationsrdquo SIAM Journal on NumericalAnalysis vol 28 no 4 pp 1047ndash1070 1991
[21] VThomeeGalerkin Finite Element Methods for Parabolic Prob-lems Springer Series in Computational Mathematics SpringerNew York NY USA 2006
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Hindawi Publishing Corporationhttpwwwhindawicom
Differential EquationsInternational Journal of
Volume 2014
Applied MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Journal of
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Mathematical PhysicsAdvances in
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OptimizationJournal of
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Function Spaces
Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of Mathematics and Mathematical Sciences
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Algebra
Discrete Dynamics in Nature and Society
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Decision SciencesAdvances in
Discrete MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
Volume 2014 Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Stochastic AnalysisInternational Journal of
Journal of Mathematics 7
Remark 9 If the initial value was chosen so that 1199060ℎminus 119906
0 le
119862ℎ2119906
02 then 120579(0) le 119906
0ℎminus119906
0+119881
ℎ1199060minus119906
0 le 119862ℎ
2119906
02
One can derive
|||120579 (119905)||| le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (48)
Lemma 10 There is a positive constant 119862 independent of ℎsuch that
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
119889119904 + 1205792
1le 119862(120579 (0)
2
1+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
2
119889119904) (49)
Proof Set Vℎ= 120579
119905in (42) to get
10038171003817100381710038171205791199051003817100381710038171003817
2
+1
2
119889
119889119905119860 (119905 120579 119868
lowast
ℎ120579)
= minus (120588119905 119868
lowast
ℎ120579119905) minus int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579119905(119905)) 119889119904
+1
2119860
119905(119905 120579 119868
lowast
ℎ120579)
+1
2[119860 (119905 120579
119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)]
le1
2
10038171003817100381710038171205881199051003817100381710038171003817
2
+1
2
1003816100381610038161003816
1003816100381610038161003816
10038161003816100381610038161205791199051003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816
2
+ 119860119905(119905 120579 119868
lowast
ℎ120579)
+1
2[119860 (119905 120579
119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)]
minus119889
119889119905int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579 (119905)) 119889119904
+ 119861 (119905 119905 120579 (119905) 119868lowast
ℎ120579 (119905)) + int
119905
0
119861119905(119905 119904 120579 (119904) 119868
lowast
ℎ120579 (119905)) 119889119904
(50)
Then
10038171003817100381710038171205791199051003817100381710038171003817
2
+119889
119889119905119860 (119905 120579 119868
lowast
ℎ120579)
le1003817100381710038171003817120588119905
1003817100381710038171003817
2
minus119889
119889119905int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579) 119889119904
+ 119862(1205792
1+ int
119905
0
120579 (119904)2
1119889119904)
+1
2[119860 (119905 120579
119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)]
(51)
In addition recall that
119860 (119905 119906ℎ 119868
lowast
ℎVℎ) minus 119860 (119905 V
ℎ 119868
lowast
ℎ119906ℎ) le 119862ℎ
1003817100381710038171003817119906ℎ
10038171003817100381710038171
1003817100381710038171003817Vℎ10038171003817100381710038171
forall119906ℎ V
ℎisin 119878
ℎ
(52)
then applying an inverse inequality and using kickbackargument we obtain
[119860 (119905 120579119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)] le 119862ℎ
100381710038171003817100381712057911990510038171003817100381710038171
1205791 le 1198621003817100381710038171003817120579119905
1003817100381710038171003817 1205791
le 1205761003817100381710038171003817120579119905
1003817100381710038171003817
2
+ 1198621205792
1
(53)
Combining these estimates we derive
10038171003817100381710038171205791199051003817100381710038171003817
2
+119889
119889119905119860 (119905 120579 119868
lowast
ℎ120579)
le1003817100381710038171003817120588119905
1003817100381710038171003817
2
minus119889
119889119905int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579) 119889119904
+ 119862(1205792
1+ int
119905
0
120579 (119904)2
1119889119904)
(54)
So after integration in time and using the weak coercivity of119860(119905 120579 119868
lowast
ℎ120579) we get
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
119889119904 + 1198880120579
2
1
le 1198880120579 (0)
2
1+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
2
119889119904
+ int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579) 119889119904 + 119862int
119905
0
120579 (119904)2
1119889119904
le 1198880120579 (0)
2
1+119888
2120579
2
1+ 119862(int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
2
+ 120579 (119904)2
1119889119904)
(55)
and by Gronwallrsquos lemma
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
119889119904 + 1198881205792
1le 119862(120579 (0)
2
1+ int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
2
119889119904) (56)
Remark 11 If 120579(0) = 0 then
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
119889119904 + 1198881205792
1le 119862ℎ
2(int
119905
0
1003817100381710038171003817119906119905
1003817100381710038171003817
2
2119889119904) (57)
Theorem 12 (error estimates in 1198712 and1198671-norms) Let 119906 119906
ℎ
be the solutions of (2) and (11) respectively Assume that 119906 119906119905isin
119871infin(119867
1
0cap 119867
2)
(a) Let 1199060ℎ
be chosen so that 1199060ℎ
minus 1199060 le 119862ℎ
2119906
02
Then for 119879 gt 0 fixed there is a constant 119862 = 119862(119879)
independent of ℎ such that for all 0 lt 119905 lt 119879
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905)
1003817100381710038171003817 le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (58)
(b) Let 1199060ℎ
be chosen so that 1199060ℎminus 119906
01
le 119862ℎ11990602
Then for 119879 gt 0 fixed there is a constant 119862 = 119862(119879)
independent of ℎ such that for all 0 lt 119905 lt 119879
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905))
10038171003817100381710038171le 119862ℎ(
10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (59)
We now prove error estimates for FVE approximations in119871119901 and119882
1119901-norms
8 Journal of Mathematics
Theorem 13 (error estimates in 119871119901 and 119882
1119901-norms) Let119906 119906
ℎbe the solutions of (2) and (11) respectively and 119906
0ℎ=
119881ℎ1199060 Assume that 119906 119906
119905isin 119871
infin(119867
1
0cap 119882
2119901) For ℎ sufficiently
small we have
1003817100381710038171003817119906 minus 119906ℎ
10038171003817100381710038170119901le 119862ℎ
2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
1003817100381710038171003817119906 minus 119906ℎ
10038171003817100381710038171119901le 119862ℎ(
10038171003817100381710038171199060
10038171003817100381710038172+ 1199062119901 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
(60)
Proof If 2 le 119901 lt infin by the following Sobolev embeddinginequality
1205790119901 le 1198621205791 (61)
then the first desired estimate follows from Lemmas 7 and 10Given 120593 isin Cinfin
0(Ω) find 120595 isin 119867
1
0(Ω) such that
119860(119905)lowast120595 = minus120593
119909 in Ω
120595 = 0 on 120597Ω
100381710038171003817100381712059510038171003817100381710038171119902
le100381710038171003817100381712059310038171003817100381710038170119902
(62)
We have
((119906 minus 119906ℎ)119909 120593) = 119860 (119905 119906 minus 119906
ℎ 120595) = 119860 (119905 119906 minus 119906
ℎ 120595 minus 119877
ℎ120595)
+ 119860 (119905 119906 minus 119906ℎ 119877
ℎ120595 minus 119868
lowast
ℎ119877ℎ120595)
minus int
119905
0
119861 (119905 119904 (119906 minus 119906ℎ) (119904) 119868
lowast
ℎ119877ℎ120595) 119889119904
minus ((119906 minus 119906ℎ)119905 119868
lowast
ℎ119877ℎ120595)
= 1198681+ 119868
2+ 119868
3+ 119868
4
100381610038161003816100381611986811003816100381610038161003816 le
1003816100381610038161003816119860 (119905 119906 minus 119877ℎ119906 120595)
1003816100381610038161003816 le 1198621003817100381710038171003817119906 minus 119877
ℎ11990610038171003817100381710038171119901
100381710038171003817100381712059510038171003817100381710038171119902
le 119862ℎ11990621199011003817100381710038171003817120595
10038171003817100381710038171119902
(63)
By Lemma 4
100381610038161003816100381611986821003816100381610038161003816 le 119860 (119905 119906 minus 119906
ℎ 119877
ℎ120595 minus 119868
lowast
ℎ119877ℎ120595)
le 119862ℎ (1003816100381610038161003816119906 minus 119906
ℎ
10038161003816100381610038161119901+ |119906|2119901)
100381710038171003817100381712059510038171003817100381710038171119902
100381610038161003816100381611986831003816100381610038161003816 le int
119905
0
1003817100381710038171003817119906 minus 119906ℎ
100381710038171003817100381711199011198891199041003817100381710038171003817120595
10038171003817100381710038171119902
100381610038161003816100381611986841003816100381610038161003816 le (
1003817100381710038171003817119906 minus 119906ℎ
1003817100381710038171003817)1003817100381710038171003817120595
1003817100381710038171003817 le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
100381710038171003817100381712059510038171003817100381710038171119902
(64)
where we have used the fact 120595 le 1205951119903 119903 gt 1 Combining
these estimates we get
1003816100381610038161003816((119906 minus 119906ℎ)119909 120593)
1003816100381610038161003816 le 119862ℎ(10038171003817100381710038171199060
10038171003817100381710038172+ 1199062119901 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
100381710038171003817100381712059510038171003817100381710038171119902
1003817100381710038171003817(119906 minus 119906ℎ)119909
10038171003817100381710038170119901= sup
((119906 minus 119906ℎ)119909 120593)
100381710038171003817100381712059310038171003817100381710038170119902
le 119862ℎ1003816100381610038161003816119906 minus 119906
ℎ
10038161003816100381610038161119901
+ 119862ℎ(10038171003817100381710038171199060
10038171003817100381710038172+ 1199062119901 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
(65)
Hence using the Poincare inequality we have for ℎ sufficientlysmall
1003817100381710038171003817119906 minus 119906ℎ
10038171003817100381710038171119901le 119862ℎ(
10038171003817100381710038171199060
10038171003817100381710038172+ 1199062119901 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (66)
We compare the relationship between covolume solutionand the Galerkin finite element solution
Corollary 14 Let ℎbe the finite element solution to (2) that
is
(ℎ119905 V
ℎ) + 119860 (119905
ℎ V
ℎ)
+ int
119905
0
119861 (119905 119904 ℎ(119904) V
ℎ) 119889119904 = (119891 V
ℎ) V
ℎisin 119878
ℎ
ℎ(0) = 119877
ℎ1199060
(67)
For ℎ sufficiently small we have
1003817100381710038171003817(ℎminus 119906
ℎ)10038171003817100381710038171119901
le 119862(
ℎ1003817100381710038171003817119906 minus 119906
ℎ
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus 119906
ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817
+int
119905
0
(1003817100381710038171003817(119906 minus 119906
ℎ) (119904)
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus
ℎ) (119904)
10038171003817100381710038171119901) 119889119904
)
le 119862 (119906) ℎ
(68)
Proof By (2) and (67)
((ℎminus 119906)
119905 V
ℎ) + 119860 (119905
ℎminus 119906 V
ℎ)
+ int
119905
0
119861 (119905 119904 (ℎminus 119906) (119904) V
ℎ) 119889119904 = 0 V
ℎisin 119878
ℎ
(69)
Consider the following auxiliary problem For any such 120593 let120595 be the solution of the following
119860(119905)lowast120595 = minus120593
119909 in Ω
120595 = 0 on 120597Ω
(70)
Journal of Mathematics 9
with1003817100381710038171003817120595
10038171003817100381710038171119902le100381710038171003817100381712059310038171003817100381710038170119902
((ℎminus 119906
ℎ)119909 120593)
= 119860 (119905 ℎminus 119906
ℎ 120595)
= 119860 (119905 ℎminus 119906
ℎ 120595 minus 119877
ℎ120595) + 119860 (119905 119906 minus 119906
ℎ 119877
ℎ120595)
minus 119860 (119905 119906 minus 119906ℎ 119868
lowast
ℎ119877ℎ120595) minus ((119906 minus 119906
ℎ)119905 119868
lowast
ℎ119877ℎ120595)
minus int
119905
0
119861 (119905 119904 (119906 minus 119906ℎ) (119904) 119868
lowast
ℎ119877ℎ120595) 119889119904
+ 119860 (119905 ℎminus 119906 119877
ℎ120595)
= [119860 (119905 119906 minus 119906ℎ 119877
ℎ120595) minus 119860 (119905 119906 minus 119906
ℎ 119868
lowast
ℎ119877ℎ120595)]
minus ((119906 minus 119906ℎ)119905 119868
lowast
ℎ119877ℎ120595) minus ((
ℎminus 119906)
119905 119877
ℎ120595)
minus int
119905
0
119861 (119905 119904 (119906 minus 119906ℎ) (119904) 119868
lowast
ℎ119877ℎ120595) 119889119904
minus int
119905
0
119861 (119905 119904 (ℎminus 119906) (119904) 119877
ℎ120595) 119889119904
= 1198681+ 119868
2+ 119868
3
(71)
On the other hand10038161003816100381610038161198681
1003816100381610038161003816 le 119862ℎ1003817100381710038171003817119906 minus 119906
ℎ
10038171003817100381710038171119901
100381710038171003817100381712059510038171003817100381710038171119902
100381610038161003816100381611986821003816100381610038161003816 le 119862 (
1003817100381710038171003817(119906 minus 119906ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817)1003817100381710038171003817120595
1003817100381710038171003817
le 119862 (1003817100381710038171003817(119906 minus 119906
ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817)1003817100381710038171003817120595
10038171003817100381710038171119902
(72)
where we have used the fact 120595 le 1205951119903 119903 gt 1
100381610038161003816100381611986831003816100381610038161003816 le int
119905
0
(1003817100381710038171003817(119906 minus 119906
ℎ) (119904)
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus
ℎ) (119904)
10038171003817100381710038171119901) 119889119904
100381710038171003817100381712059510038171003817100381710038171119902
1003817100381710038171003817(ℎminus 119906
ℎ)119909
10038171003817100381710038170119901
= sup120593isinCinfin0
((ℎminus 119906
ℎ)119909 120593)
100381710038171003817100381712059310038171003817100381710038170119902
le 119862(
ℎ1003817100381710038171003817119906 minus 119906
ℎ
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus 119906
ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817
+int
119905
0
(1003817100381710038171003817(119906 minus 119906
ℎ) (119904)
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus
ℎ) (119904)
10038171003817100381710038171119901) 119889119904
)
(73)
We deduce the result from the known finite element esti-mates
Remark 15 In order to estimate (119906 minus 119906ℎ)119905 by differentiating
(42) with respect to 119905 we obtain
(120579119905119905 119868
lowast
ℎVℎ) + 119860 (119905 120579
119905 119868
lowast
ℎVℎ) + 119860
119905(119905 120579
119905 119868
lowast
ℎVℎ)
+ 119861 (119905 119905 120579 119868lowast
ℎVℎ) + int
119905
0
119861119905(119905 119904 120579 (119904) 119868
lowast
ℎVℎ) 119889119904
= minus (120588119905119905 119868
lowast
ℎVℎ)
(74)
Setting Vℎ= 120579
119905 we obtain
1
2
119889
119889119905
1003816100381610038161003816
1003816100381610038161003816
10038161003816100381610038161205791199051003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816
2
+ 1198881003817100381710038171003817120579119905
1003817100381710038171003817
2
1le1003817100381710038171003817120588119905119905
1003817100381710038171003817
10038171003817100381710038171205791199051003817100381710038171003817
+1
21198881003817100381710038171003817120579119905
1003817100381710038171003817
2
1+ 119862120579
2
1+ int
119905
0
1205792
1119889119904
le1003817100381710038171003817120588119905119905
1003817100381710038171003817
10038171003817100381710038171205791199051003817100381710038171003817 +
1
21198881003817100381710038171003817120579119905
1003817100381710038171003817
2
1+ 119862int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
1119889119904
(75)
Using kickback argument integrating and applying Gron-wallrsquos lemma we deduce
10038171003817100381710038171205791199051003817100381710038171003817 le 119862(
1003817100381710038171003817120579119905 (0)1003817100381710038171003817 + int
119905
0
100381710038171003817100381712058811990511990510038171003817100381710038171119889119904)
le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+10038171003817100381710038171199061
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904)
(76)
5 The Lumped Mass Finite VolumeElement Method
In this section we restrict our study to the 2D case A simpleway to define the lumped mass scheme [21] is to replace themass matrix 119872
ℎin (14) by the diagonal matrix 119872
ℎobtained
by taking for its diagonal elements the numbers 119872ℎ119894119894
=
sum119873ℎ
119895=1119872
ℎ119894119895or by lumping all masses in one row into the
diagonal entryThismakes the inversion of thematrix in frontof1205721015840
(119905) a trivialityWewill therefore study thematrix problem
119872ℎ1205721015840(119905) + 119860
ℎ(119905) 120572 (119905) + int
119905
0
119861ℎ(119905 119904) 120572 (119904) 119889119904 = 119865
ℎ(119905) (77)
We know that the lumped mass method defined by (77)above is equivalent to
(119868lowast
ℎ119906ℎ119905 119868
lowast
ℎVℎ) + 119860 (119905 119906
ℎ 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 119906ℎ(119904) 119868
lowast
ℎVℎ) 119889119904
= (119891 119868lowast
ℎVℎ) V
ℎisin 119878
ℎ
(78)
Our alternative interpretation of this procedure will beto think of (77) as being obtained by evaluating the firstterm in (78) by numerical quadrature Let 119870 be a triangle ofthe triangulation 119879
ℎ let 119909
119895 119895 = 1 2 3 be its vertices and
consider the quadrature formula
119876119870ℎ
(119891) =1
3area119870
3
sum
119895=1
119891 (119909119895) ≃ int
119870
119891119889119909 (79)
We may then define the associated bilinear form in 119878ℎtimes
119878lowast
ℎ using the quadrature scheme by the following
(Vℎ 120578
ℎ)ℎ= sum
119870isin119879ℎ
119876119870ℎ
(Vℎ120578ℎ) = sum
119909119894isin119873119886
ℎ
Vℎ(119909
119894) 120578
ℎ(119909
119894)10038161003816100381610038161003816119881119909119894
10038161003816100381610038161003816
forallVℎisin 119878
ℎ 120578
ℎisin 119878
lowast
ℎ
(80)
10 Journal of Mathematics
We note that Vℎ2
ℎ= (V
ℎ 119868
lowast
ℎVℎ)ℎis a norm in 119878
ℎwhich is
equivalent to the 1198712-norm uniformly in ℎ that is there existtwo positive constants 119862
1and 119862
2such that for all V
ℎisin 119878
ℎ we
have
1198620
1003817100381710038171003817Vℎ1003817100381710038171003817 le
1003817100381710038171003817Vℎ1003817100381710038171003817ℎ
le 1198621
1003817100381710038171003817Vℎ1003817100381710038171003817 forallV
ℎisin 119878
ℎ (81)
We note that the aforementioned definition (Vℎ 120578
ℎ)ℎmay
be used also for 120578ℎisin 119878
ℎand that (V
ℎ 119908
ℎ)ℎ= (V
ℎ 119868
lowast
ℎ119908
ℎ)ℎfor
Vℎ 119908
ℎisin 119878
ℎ
The lumpedmass method defined by (78) is equivalent to
(119906ℎ119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 119906
ℎ 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 119906ℎ(119904) 119868
lowast
ℎVℎ) 119889119904
= (119891 119868lowast
ℎVℎ) V
ℎisin 119878
ℎ
(82)
We introduce the quadrature error
120576ℎ(V
ℎ 119908
ℎ) = (V
ℎ 119908
ℎ)ℎminus (V
ℎ 119908
ℎ) (83)
Lemma 16 (see [21]) Let Vℎ 119908
ℎisin 119878
ℎ Then
1003816100381610038161003816120576ℎ (Vℎ 119908ℎ)1003816100381610038161003816 le 119862ℎ
2 1003817100381710038171003817nablaVℎ1003817100381710038171003817
1003817100381710038171003817nabla119908ℎ
1003817100381710038171003817 (84)
Theorem 17 Let 119906ℎand 119906 be the solutions of (82) and (2)
respectively and assume 119906ℎ(0) = 119877
ℎ1199060 Then we have for the
error in the lumped mass semidiscrete method for 119905 ge 0 thefollowing
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905)
1003817100381710038171003817 le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ 1199062 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (85)
Proof In order to estimate 120579 we write
(120579119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 120579 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎVℎ) 119889119904
= (119906ℎ119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 119906
ℎ 119868
lowast
ℎVℎ)
+ int
119905
0
119861 (119905 119904 119906ℎ(119904) 119868
lowast
ℎVℎ) 119889119904
minus ((119881ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus 119860 (119905 119881
ℎ119906 119868
lowast
ℎVℎ)
minus int
119905
0
119861 (119905 119904 119881ℎ119906 (119904) 119868
lowast
ℎVℎ) 119889119904
= (119891 119868lowast
ℎVℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus 119860 (119905 119906 119868
lowast
ℎVℎ)
minus int
119905
0
119861 (119905 119904 119906 (119904) 119868lowast
ℎVℎ)
= (119906119905 119868
lowast
ℎVℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)ℎ
= minus (120588119905 119868
lowast
ℎVℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)ℎ+ ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
(86)
We rewrite
((119881ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
= ((119881ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus ((119881
ℎ119906)
119905 V
ℎ)
+ ((119881ℎ119906)
119905 V
ℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
= 120576ℎ((119881
ℎ119906)
119905 V
ℎ) + ((119881
ℎ119906)
119905 V
ℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
(120579119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 120579 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎVℎ) 119889119904
= minus (120588119905 119868
lowast
ℎVℎ) + 120576
ℎ((119881
ℎ119906)
119905 V
ℎ)
+ ((119881ℎ119906)
119905 V
ℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
(87)
Setting Vℎ= 120579 in (87) we obtain
1
2
119889
119889119905120579
2
ℎ+ 119888
01205792
1
le1003817100381710038171003817120588119905
1003817100381710038171003817 120579 +1
21198880120579
2
1+ 119862int
119905
0
1205792
1119889119904
+ 120576ℎ((119881
ℎ119906)
119905 120579) + ((119881
ℎ119906)
119905 120579) minus ((119881
ℎ119906)
119905 119868
lowast
ℎ120579)
(88)
Using Lemma 16 and the inverse estimate we get1003816100381610038161003816120576ℎ (119881ℎ
119906119905 120579)
1003816100381610038161003816 le 119862ℎ2 1003817100381710038171003817nabla(119881ℎ
119906)119905
1003817100381710038171003817 nabla120579
le 119862ℎ2 1003817100381710038171003817nabla119906119905
1003817100381710038171003817 nabla120579
le 119862ℎ1003817100381710038171003817nabla119906119905
1003817100381710038171003817 120579
(89)
we have1003816100381610038161003816((119881ℎ
119906)119905 120579) minus ((119881
ℎ119906)
119905 119868
lowast
ℎ120579)1003816100381610038161003816 le 119862ℎ
1003817100381710038171003817nabla119906119905
1003817100381710038171003817 120579 (90)
Using Youngrsquos inequality and Gronwallrsquos lemma to eliminate120579
1on the right-hand side and using integration in 119905 we get
the result
1
2
119889
119889119905120579
2
ℎ+ 119888
0 120579 le1003817100381710038171003817120588119905
1003817100381710038171003817 120579 + 119862ℎ1003817100381710038171003817nabla119906119905
1003817100381710038171003817 120579 (91)
Using Youngrsquos inequality to eliminate 120579 on the right handside it becomes
Using integration in 119905 we get the result
We will now show that the 1198671-norm error bound of
theorem remains valid for the lumped mass method (82)
Theorem 18 Let 119906ℎand 119906 be the solutions of (82) and (2)
respectively and assume
119906ℎ(0) = 119877
ℎ1199060
10038171003817100381710038171199061ℎ(0) minus 119906
1
1003817100381710038171003817 le 119862ℎ210038171003817100381710038171199061
10038171003817100381710038172 (92)
Then we have for the error in the lumped mass semidiscretemethod for 119905 ge 0 the following
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905)
10038171003817100381710038171le 119862ℎ
2(10038171003817100381710038171199060
10038171003817100381710038172+10038171003817100381710038171199061
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904)
(93)
Journal of Mathematics 11
Proof Setting Vℎ= 120579
119905in (87) we obtain
10038171003817100381710038171205791199051003817100381710038171003817
2
ℎ+1
2
119889
119889119905119860 (119905 120579 119868
lowast
ℎ120579)
=1
2119860
119905(119905 120579 119868
lowast
ℎ120579) +
1
2[119860 (119905 120579
119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)]
119861 (119905 119905 120579 (119905) 119868lowast
ℎ120579 (119905)) + int
119905
0
119861119905(119905 119904 120579 (119904) 119868
lowast
ℎ120579 (119905)) 119889119904
minus119889
119889119905int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579 (119905)) 119889119904 minus (120588
119905 119868
lowast
ℎ120579119905)
minus 120576ℎ((119881
ℎ119906)
119905 120579
119905) + ((119881
ℎ119906)
119905 120579) minus ((119881
ℎ119906)
119905 119868
lowast
ℎ120579)
(94)
It follows thus that using integration in 119905 and Gronwallrsquoslemma we have
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
ℎ+ 120579
2
1le 119862nabla120579 (0)
2+ 119862int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
10038171003817100381710038171205791199051003817100381710038171003817 119889119904
+ 119862ℎ2int
119905
0
1003817100381710038171003817119906119905
1003817100381710038171003817
2
1119889119904
(95)
6 Full Discretization
Let 120597119880119899= (119880
119899minus119880
119899minus1)119896 be the backward difference quotient
of 119880119899 assume that 119860ℎ
= 119875ℎ119860 is a discrete analogue of 119860
(similarly 119861ℎ
= 119875ℎ119861) where 119875
ℎ 119871
2(Ω) rarr 119878
lowast
ℎthe 119871
2
projection is defined by
(119875ℎV 119868lowast
ℎVℎ) = (V 119868lowast
ℎVℎ) V isin 119871
2(Ω) V
ℎisin 119878
ℎ (96)
In order to define fully discrete approximation of (11) wediscretize the time by taking 119905
119899= 119899119896 119896 gt 0 119899 = 1 2 and
use the numerical quadrature
int
119905119899minus12
0
119892 (119904) 119889119904 asymp
119899
sum
119896=1
120596119899119896119892 (119905
119896minus12) 119905
119899minus12= (119899 minus
1
2) 119896
(97)
Here 120596119899119896 are the integrationweights andwe assume that
the following error estimate is valid
119902119899(119892) = int
119905119899minus12
0
119892 (119904) 119889119904minus
119899
sum
119896=1
120596119899119896119892 (119905
119896minus12)
le 1198621198962int
119905119899
0
(10038161003816100381610038161003816119892101584010038161003816100381610038161003816+100381610038161003816100381610038161198921015840101584010038161003816100381610038161003816) 119889119904
(98)
Now define our complete discrete FVE approximation of(11) by the following find 119880
119899isin 119878
ℎfor 119899 = 1 2 such that
for all Vℎisin 119878
ℎ
(120597119880119899 119868
lowast
ℎVℎ) + 119860 (119905
119899minus12 119880
119899minus12 119868
lowast
ℎVℎ)
+
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12 119880
119896minus12 119868
lowast
ℎVℎ)
= (119891119899minus12
119868lowast
ℎVℎ)
1198800 in 119878
ℎ
(99)
where 119880119899minus12= (119880
119899+ 119880
119899minus1)2
Theorem 19 Let 119906(119905) and 119880119899 be the solutions of problem (2)
and its complete discrete scheme (99) respectively Then forany 119879 gt 0 there exists a positive constant 119862 = 119862(119879) gt 0independent of ℎ such that for 0 lt 119905
119899le 119879
1003817100381710038171003817119906 (119905119899) minus 1198801198991003817100381710038171003817
le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905119899
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
+ 1198621198962(int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905119905
1003817100381710038171003817) 119889119904)
(100)
Proof Let us split the error into two parts 119906(119905119899) minus 119880
119899= 120588
119899+
120579119899 where 120588
119899= 119906(119905
119899)minus119881
ℎ119906(119905
119899) and 120579119899 = 119881
ℎ119906(119905
119899)minus119880
119899 and let119882 = 119881
ℎ119906(119905) isin 119878
ℎbe the Ritz-Volterra projection of 119906 Then
from (2) and (99) we have for all Vℎisin 119878
ℎthe following
(120597120579119899 119868
lowast
ℎVℎ) + 119860 (119905
119899minus12 120579
119899minus12 119868
lowast
ℎVℎ)
+
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12 120579
119896minus12 119868
lowast
ℎVℎ)
= minus (119903119899 119868
lowast
ℎVℎ) forallV
ℎisin 119878
ℎ
(101)
where
119903119899= 119903
1
119899+ 119903
2
119899+ 119903
3
119899+ 119903
4
119899
1199031
119899= 120597120588
119899
1199032
119899= 120597119906 (119905
119899) minus 119906
119905(119905
119899minus12)
1199033
119899= 119860(119905
119899minus12(119906 (119905
119899) + 119906 (119905
119899minus1))
2minus 119906 (119905
119899minus12))
1199034
119899= 119902
119899(119861
ℎ119882)
=
119899
sum
119896=1
120596119899119896119861ℎ(119905
119899minus12 119905
119896minus12119882
119896minus12 119868
lowast
ℎVℎ)
minus int
119905119899minus12
0
119861 (119905119899 119904119882 (119904) 119868
lowast
ℎVℎ) 119889119904
(102)
In fact by Taylor expansion
119906119899+1
= 119906119899+ 119896119906
1015840(119905
119899) + int
119905119899+1
119905119899
11990610158401015840(119904) (119905
119899+1minus 119904) 119889119904
= 119906119899+ 119896119906
1015840(119905
119899) +
1198962
211990610158401015840(119905
119899) +
1198963
6119906(3)
(119905119899)
+1
6int
119905119899+1
119905119899
119906(4)
(119904) (119905119899+1
minus 119904)3
119889119904
(103)
12 Journal of Mathematics
we have100381710038171003817100381710038171199031
119899
10038171003817100381710038171003817=
10038171003817100381710038171003817120597120588
11989910038171003817100381710038171003817le
1
119896int
119905119899
119905119899minus1
10038171003817100381710038171205881199051003817100381710038171003817 119889119904 le 119862
ℎ2
119896int
119905119899
119905119899minus1
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
100381710038171003817100381710038171199032
119899
10038171003817100381710038171003817=
10038171003817100381710038171003817120597119906 (119905
119899) minus 119906
119905(119905
119899minus12)10038171003817100381710038171003817
=1
119896
100381710038171003817100381710038171003817100381710038171003817
int
119905119899
119905119899minus1
(119906119905(119904) minus 119906
119905(119905
119899minus12)) 119889119904
100381710038171003817100381710038171003817100381710038171003817
le 119862119896int
119905119899
119905119899minus1
10038171003817100381710038171003817119906(3)
(119904)10038171003817100381710038171003817119889119904
100381710038171003817100381710038171199033
119899
10038171003817100381710038171003817=
100381710038171003817100381710038171003817100381710038171003817
119860(119905119899minus12
119906 (119905
119899) + 119906 (119905
119899minus1)
2minus 119906 (119905
119899minus12) 119868
lowast
ℎVℎ)
100381710038171003817100381710038171003817100381710038171003817
le 119862119896int
119905119899
119905119899minus1
1003817100381710038171003817119860119906119905119905(119904)
1003817100381710038171003817 119889119904 le 119862119896int
119905119899
119905119899minus1
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
(104)
In addition the quadrature error satisfies100381710038171003817100381710038171199034
119899
10038171003817100381710038171003817= 119902
119899minus12(119861
ℎ119882)
=
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12119882
119896minus12 119868
lowast
ℎVℎ)
minus int
119905119899minus12
0
119861 (119905119899 119904119882 (119904) 119868
lowast
ℎVℎ) 119889119904
le 1198621198962int
119905119899
0
1003817100381710038171003817(119861ℎ119882)
119904119904
1003817100381710038171003817 119889119904
le 1198621198962int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172) 119889119904
119896
119873
sum
119899=1
10038171003817100381710038171199031198991003817100381710038171003817 le 119862ℎ
2int
119905119899
0
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
+ 1198621198962int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172+10038171003817100381710038171003817119906(3)10038171003817100381710038171003817
) 119889119904
(105)
Taking Vℎ= 120579
119899minus12 in (101) and noting that (120597120579119899 119868lowastℎ120579119899minus12
) =
(12)120597|||120579119899|||
2 there is1003816100381610038161003816
1003816100381610038161003816
10038161003816100381610038161205791198991003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816
2
minus10038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus110038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
+ 211989611988810038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus1210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
1
le 1198621198962
119899
sum
119896=1
10038171003817100381710038171003817120579119896minus12100381710038171003817100381710038171
10038171003817100381710038171003817120579119899minus12100381710038171003817100381710038171
+ 1198621198961003817100381710038171003817119903119899
1003817100381710038171003817
10038171003817100381710038171003817120579119899minus1210038171003817100381710038171003817
le11989611988810038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus1210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
1+ 119862119896
2
119899
sum
119896=1
10038171003817100381710038171003817120579119896minus1210038171003817100381710038171003817
2
1+ 119862119896
10038171003817100381710038171199031198991003817100381710038171003817
10038171003817100381710038171003817120579119899minus1210038171003817100381710038171003817
(106)
Summing from 119899 = 1 to 119873 and then after cancelling thecommon factor and using Gronwallrsquos lemma we obtain
10038161003816100381610038161003816
10038161003816100381610038161003816
1003816100381610038161003816100381612057911987310038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
le 11986210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579010038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
+ 119862119896
119873
sum
119896=1
10038171003817100381710038171199031198991003817100381710038171003817 (
1003817100381710038171003817100381712057911989610038171003817100381710038171003817
+10038171003817100381710038171003817120579119896minus1210038171003817100381710038171003817
) (107)
and then
10038161003816100381610038161003816
10038161003816100381610038161003816
1003816100381610038161003816100381612057911987310038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816le 119862
10038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579010038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816+ 119862119896
119873
sum
119899=1
10038171003817100381710038171199031198991003817100381710038171003817
(108)
the theorem follows from the estimates of 120588119899 and 119903119899
References
[1] Z Q Cai ldquoOn the finite volume element methodrdquo NumerischeMathematik vol 58 no 7 pp 713ndash735 1991
[2] S H Chou and D Y Kwak ldquoAnalysis and convergence of aMAC-like scheme for the generalized Stokes problemrdquo Numer-ical Methods for Partial Differential Equations vol 13 no 2 pp147ndash162 1997
[3] P Chatzipantelidis ldquoA finite volume method based on theCrouzeix-Raviart element for elliptic PDErsquos in two dimensionsrdquoNumerische Mathematik vol 82 no 3 pp 409ndash432 1999
[4] P Chatzipantelidis ldquoFinite volumemethods for elliptic PDErsquos anew approachrdquo Mathematical Modelling and Numerical Analy-sis vol 36 no 2 pp 307ndash324 2002
[5] P Chatzipantelidis R D Lazarov and V Thomee ldquoErrorestimates for a finite volume element method for parabolicequations in convex polygonal domainsrdquoNumericalMethods forPartial Differential Equations vol 20 no 5 pp 650ndash674 2004
[6] R E Ewing R D Lazarov and Y Lin ldquoFinite volume elementapproximations of nonlocal in time one-dimensional flows inporous mediardquo Computing vol 64 no 2 pp 157ndash182 2000
[7] R Ewing R Lazarov and Y Lin ldquoFinite volume elementapproximations of nonlocal reactive flows in porous mediardquoNumericalMethods for Partial Differential Equations vol 16 no3 pp 285ndash311 2000
[8] R E Ewing T Lin andY Lin ldquoOn the accuracy of the finite vol-ume element method based on piecewise linear polynomialsrdquoSIAM Journal on Numerical Analysis vol 39 no 6 pp 1865ndash1888 2002
[9] R K Sinha and J Geiser ldquoError estimates for finite volumeelement methods for convection-diffusion-reaction equationsrdquoApplied Numerical Mathematics vol 57 no 1 pp 59ndash72 2007
[10] S H Chou ldquoAnalysis and convergence of a covolume methodfor the generalized Stokes problemrdquo Mathematics of Computa-tion vol 66 no 217 pp 85ndash104 1997
[11] M Berggren ldquoA vertex-centered dual discontinuous Galerkinmethodrdquo Journal of Computational and Applied Mathematicsvol 192 no 1 pp 175ndash181 2006
[12] S H Chou and D Y Kwak ldquoMultigrid algorithms for a vertex-centered covolume method for elliptic problemsrdquo NumerischeMathematik vol 90 no 3 pp 441ndash458 2002
[13] R Eymard T Gallouet and R Herbin Finite Volume MethodsHandbook of Numerical Analysis North-Holland AmsterdamThe Netherlands 2000
[14] V R Voller Basic Control Volume Finite Element Methods forFluids and Solids World Scientific Publishing 2009
[15] J Huang and S Xi ldquoOn the finite volume element method forgeneral self-adjoint elliptic problemsrdquo SIAM Journal on Numer-ical Analysis vol 35 no 5 pp 1762ndash1774 1998
[16] X Ma S Shu and A Zhou ldquoSymmetric finite volume discreti-zations for parabolic problemsrdquo Computer Methods in AppliedMechanics and Engineering vol 192 no 39-40 pp 4467ndash44852003
[17] R D Lazarov and S Z Tomov ldquoAdaptive finite volume elementmethod for convection-diffusion-reaction problems in 3-Drdquo inScientific Computing and Applications vol 7 of Advances inComputation Theory and Practice pp 91ndash106 Nova SciencePublishers Huntington NY USA 2001
[18] I DMishevFinite volume and finite volume elementmethods fornon-symmetric problems [PhD thesis] Texas AampM University1997 Technical Report ISC-96-04-MATH
Journal of Mathematics 13
[19] C Chen and T Shih Finite Element Methods for Integrodifferen-tial Equations World Scientific Publishing Singapore 1998
[20] Y P Lin V Thomee and L B Wahlbin ldquoRitz-Volterra pro-jections to finite-element spaces and applications to integrod-ifferential and related equationsrdquo SIAM Journal on NumericalAnalysis vol 28 no 4 pp 1047ndash1070 1991
[21] VThomeeGalerkin Finite Element Methods for Parabolic Prob-lems Springer Series in Computational Mathematics SpringerNew York NY USA 2006
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Differential EquationsInternational Journal of
Volume 2014
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Mathematical PhysicsAdvances in
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OptimizationJournal of
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Function Spaces
Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Algebra
Discrete Dynamics in Nature and Society
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Decision SciencesAdvances in
Discrete MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
Volume 2014 Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Stochastic AnalysisInternational Journal of
8 Journal of Mathematics
Theorem 13 (error estimates in 119871119901 and 119882
1119901-norms) Let119906 119906
ℎbe the solutions of (2) and (11) respectively and 119906
0ℎ=
119881ℎ1199060 Assume that 119906 119906
119905isin 119871
infin(119867
1
0cap 119882
2119901) For ℎ sufficiently
small we have
1003817100381710038171003817119906 minus 119906ℎ
10038171003817100381710038170119901le 119862ℎ
2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
1003817100381710038171003817119906 minus 119906ℎ
10038171003817100381710038171119901le 119862ℎ(
10038171003817100381710038171199060
10038171003817100381710038172+ 1199062119901 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
(60)
Proof If 2 le 119901 lt infin by the following Sobolev embeddinginequality
1205790119901 le 1198621205791 (61)
then the first desired estimate follows from Lemmas 7 and 10Given 120593 isin Cinfin
0(Ω) find 120595 isin 119867
1
0(Ω) such that
119860(119905)lowast120595 = minus120593
119909 in Ω
120595 = 0 on 120597Ω
100381710038171003817100381712059510038171003817100381710038171119902
le100381710038171003817100381712059310038171003817100381710038170119902
(62)
We have
((119906 minus 119906ℎ)119909 120593) = 119860 (119905 119906 minus 119906
ℎ 120595) = 119860 (119905 119906 minus 119906
ℎ 120595 minus 119877
ℎ120595)
+ 119860 (119905 119906 minus 119906ℎ 119877
ℎ120595 minus 119868
lowast
ℎ119877ℎ120595)
minus int
119905
0
119861 (119905 119904 (119906 minus 119906ℎ) (119904) 119868
lowast
ℎ119877ℎ120595) 119889119904
minus ((119906 minus 119906ℎ)119905 119868
lowast
ℎ119877ℎ120595)
= 1198681+ 119868
2+ 119868
3+ 119868
4
100381610038161003816100381611986811003816100381610038161003816 le
1003816100381610038161003816119860 (119905 119906 minus 119877ℎ119906 120595)
1003816100381610038161003816 le 1198621003817100381710038171003817119906 minus 119877
ℎ11990610038171003817100381710038171119901
100381710038171003817100381712059510038171003817100381710038171119902
le 119862ℎ11990621199011003817100381710038171003817120595
10038171003817100381710038171119902
(63)
By Lemma 4
100381610038161003816100381611986821003816100381610038161003816 le 119860 (119905 119906 minus 119906
ℎ 119877
ℎ120595 minus 119868
lowast
ℎ119877ℎ120595)
le 119862ℎ (1003816100381610038161003816119906 minus 119906
ℎ
10038161003816100381610038161119901+ |119906|2119901)
100381710038171003817100381712059510038171003817100381710038171119902
100381610038161003816100381611986831003816100381610038161003816 le int
119905
0
1003817100381710038171003817119906 minus 119906ℎ
100381710038171003817100381711199011198891199041003817100381710038171003817120595
10038171003817100381710038171119902
100381610038161003816100381611986841003816100381610038161003816 le (
1003817100381710038171003817119906 minus 119906ℎ
1003817100381710038171003817)1003817100381710038171003817120595
1003817100381710038171003817 le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
100381710038171003817100381712059510038171003817100381710038171119902
(64)
where we have used the fact 120595 le 1205951119903 119903 gt 1 Combining
these estimates we get
1003816100381610038161003816((119906 minus 119906ℎ)119909 120593)
1003816100381610038161003816 le 119862ℎ(10038171003817100381710038171199060
10038171003817100381710038172+ 1199062119901 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
100381710038171003817100381712059510038171003817100381710038171119902
1003817100381710038171003817(119906 minus 119906ℎ)119909
10038171003817100381710038170119901= sup
((119906 minus 119906ℎ)119909 120593)
100381710038171003817100381712059310038171003817100381710038170119902
le 119862ℎ1003816100381610038161003816119906 minus 119906
ℎ
10038161003816100381610038161119901
+ 119862ℎ(10038171003817100381710038171199060
10038171003817100381710038172+ 1199062119901 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
(65)
Hence using the Poincare inequality we have for ℎ sufficientlysmall
1003817100381710038171003817119906 minus 119906ℎ
10038171003817100381710038171119901le 119862ℎ(
10038171003817100381710038171199060
10038171003817100381710038172+ 1199062119901 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (66)
We compare the relationship between covolume solutionand the Galerkin finite element solution
Corollary 14 Let ℎbe the finite element solution to (2) that
is
(ℎ119905 V
ℎ) + 119860 (119905
ℎ V
ℎ)
+ int
119905
0
119861 (119905 119904 ℎ(119904) V
ℎ) 119889119904 = (119891 V
ℎ) V
ℎisin 119878
ℎ
ℎ(0) = 119877
ℎ1199060
(67)
For ℎ sufficiently small we have
1003817100381710038171003817(ℎminus 119906
ℎ)10038171003817100381710038171119901
le 119862(
ℎ1003817100381710038171003817119906 minus 119906
ℎ
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus 119906
ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817
+int
119905
0
(1003817100381710038171003817(119906 minus 119906
ℎ) (119904)
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus
ℎ) (119904)
10038171003817100381710038171119901) 119889119904
)
le 119862 (119906) ℎ
(68)
Proof By (2) and (67)
((ℎminus 119906)
119905 V
ℎ) + 119860 (119905
ℎminus 119906 V
ℎ)
+ int
119905
0
119861 (119905 119904 (ℎminus 119906) (119904) V
ℎ) 119889119904 = 0 V
ℎisin 119878
ℎ
(69)
Consider the following auxiliary problem For any such 120593 let120595 be the solution of the following
119860(119905)lowast120595 = minus120593
119909 in Ω
120595 = 0 on 120597Ω
(70)
Journal of Mathematics 9
with1003817100381710038171003817120595
10038171003817100381710038171119902le100381710038171003817100381712059310038171003817100381710038170119902
((ℎminus 119906
ℎ)119909 120593)
= 119860 (119905 ℎminus 119906
ℎ 120595)
= 119860 (119905 ℎminus 119906
ℎ 120595 minus 119877
ℎ120595) + 119860 (119905 119906 minus 119906
ℎ 119877
ℎ120595)
minus 119860 (119905 119906 minus 119906ℎ 119868
lowast
ℎ119877ℎ120595) minus ((119906 minus 119906
ℎ)119905 119868
lowast
ℎ119877ℎ120595)
minus int
119905
0
119861 (119905 119904 (119906 minus 119906ℎ) (119904) 119868
lowast
ℎ119877ℎ120595) 119889119904
+ 119860 (119905 ℎminus 119906 119877
ℎ120595)
= [119860 (119905 119906 minus 119906ℎ 119877
ℎ120595) minus 119860 (119905 119906 minus 119906
ℎ 119868
lowast
ℎ119877ℎ120595)]
minus ((119906 minus 119906ℎ)119905 119868
lowast
ℎ119877ℎ120595) minus ((
ℎminus 119906)
119905 119877
ℎ120595)
minus int
119905
0
119861 (119905 119904 (119906 minus 119906ℎ) (119904) 119868
lowast
ℎ119877ℎ120595) 119889119904
minus int
119905
0
119861 (119905 119904 (ℎminus 119906) (119904) 119877
ℎ120595) 119889119904
= 1198681+ 119868
2+ 119868
3
(71)
On the other hand10038161003816100381610038161198681
1003816100381610038161003816 le 119862ℎ1003817100381710038171003817119906 minus 119906
ℎ
10038171003817100381710038171119901
100381710038171003817100381712059510038171003817100381710038171119902
100381610038161003816100381611986821003816100381610038161003816 le 119862 (
1003817100381710038171003817(119906 minus 119906ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817)1003817100381710038171003817120595
1003817100381710038171003817
le 119862 (1003817100381710038171003817(119906 minus 119906
ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817)1003817100381710038171003817120595
10038171003817100381710038171119902
(72)
where we have used the fact 120595 le 1205951119903 119903 gt 1
100381610038161003816100381611986831003816100381610038161003816 le int
119905
0
(1003817100381710038171003817(119906 minus 119906
ℎ) (119904)
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus
ℎ) (119904)
10038171003817100381710038171119901) 119889119904
100381710038171003817100381712059510038171003817100381710038171119902
1003817100381710038171003817(ℎminus 119906
ℎ)119909
10038171003817100381710038170119901
= sup120593isinCinfin0
((ℎminus 119906
ℎ)119909 120593)
100381710038171003817100381712059310038171003817100381710038170119902
le 119862(
ℎ1003817100381710038171003817119906 minus 119906
ℎ
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus 119906
ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817
+int
119905
0
(1003817100381710038171003817(119906 minus 119906
ℎ) (119904)
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus
ℎ) (119904)
10038171003817100381710038171119901) 119889119904
)
(73)
We deduce the result from the known finite element esti-mates
Remark 15 In order to estimate (119906 minus 119906ℎ)119905 by differentiating
(42) with respect to 119905 we obtain
(120579119905119905 119868
lowast
ℎVℎ) + 119860 (119905 120579
119905 119868
lowast
ℎVℎ) + 119860
119905(119905 120579
119905 119868
lowast
ℎVℎ)
+ 119861 (119905 119905 120579 119868lowast
ℎVℎ) + int
119905
0
119861119905(119905 119904 120579 (119904) 119868
lowast
ℎVℎ) 119889119904
= minus (120588119905119905 119868
lowast
ℎVℎ)
(74)
Setting Vℎ= 120579
119905 we obtain
1
2
119889
119889119905
1003816100381610038161003816
1003816100381610038161003816
10038161003816100381610038161205791199051003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816
2
+ 1198881003817100381710038171003817120579119905
1003817100381710038171003817
2
1le1003817100381710038171003817120588119905119905
1003817100381710038171003817
10038171003817100381710038171205791199051003817100381710038171003817
+1
21198881003817100381710038171003817120579119905
1003817100381710038171003817
2
1+ 119862120579
2
1+ int
119905
0
1205792
1119889119904
le1003817100381710038171003817120588119905119905
1003817100381710038171003817
10038171003817100381710038171205791199051003817100381710038171003817 +
1
21198881003817100381710038171003817120579119905
1003817100381710038171003817
2
1+ 119862int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
1119889119904
(75)
Using kickback argument integrating and applying Gron-wallrsquos lemma we deduce
10038171003817100381710038171205791199051003817100381710038171003817 le 119862(
1003817100381710038171003817120579119905 (0)1003817100381710038171003817 + int
119905
0
100381710038171003817100381712058811990511990510038171003817100381710038171119889119904)
le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+10038171003817100381710038171199061
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904)
(76)
5 The Lumped Mass Finite VolumeElement Method
In this section we restrict our study to the 2D case A simpleway to define the lumped mass scheme [21] is to replace themass matrix 119872
ℎin (14) by the diagonal matrix 119872
ℎobtained
by taking for its diagonal elements the numbers 119872ℎ119894119894
=
sum119873ℎ
119895=1119872
ℎ119894119895or by lumping all masses in one row into the
diagonal entryThismakes the inversion of thematrix in frontof1205721015840
(119905) a trivialityWewill therefore study thematrix problem
119872ℎ1205721015840(119905) + 119860
ℎ(119905) 120572 (119905) + int
119905
0
119861ℎ(119905 119904) 120572 (119904) 119889119904 = 119865
ℎ(119905) (77)
We know that the lumped mass method defined by (77)above is equivalent to
(119868lowast
ℎ119906ℎ119905 119868
lowast
ℎVℎ) + 119860 (119905 119906
ℎ 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 119906ℎ(119904) 119868
lowast
ℎVℎ) 119889119904
= (119891 119868lowast
ℎVℎ) V
ℎisin 119878
ℎ
(78)
Our alternative interpretation of this procedure will beto think of (77) as being obtained by evaluating the firstterm in (78) by numerical quadrature Let 119870 be a triangle ofthe triangulation 119879
ℎ let 119909
119895 119895 = 1 2 3 be its vertices and
consider the quadrature formula
119876119870ℎ
(119891) =1
3area119870
3
sum
119895=1
119891 (119909119895) ≃ int
119870
119891119889119909 (79)
We may then define the associated bilinear form in 119878ℎtimes
119878lowast
ℎ using the quadrature scheme by the following
(Vℎ 120578
ℎ)ℎ= sum
119870isin119879ℎ
119876119870ℎ
(Vℎ120578ℎ) = sum
119909119894isin119873119886
ℎ
Vℎ(119909
119894) 120578
ℎ(119909
119894)10038161003816100381610038161003816119881119909119894
10038161003816100381610038161003816
forallVℎisin 119878
ℎ 120578
ℎisin 119878
lowast
ℎ
(80)
10 Journal of Mathematics
We note that Vℎ2
ℎ= (V
ℎ 119868
lowast
ℎVℎ)ℎis a norm in 119878
ℎwhich is
equivalent to the 1198712-norm uniformly in ℎ that is there existtwo positive constants 119862
1and 119862
2such that for all V
ℎisin 119878
ℎ we
have
1198620
1003817100381710038171003817Vℎ1003817100381710038171003817 le
1003817100381710038171003817Vℎ1003817100381710038171003817ℎ
le 1198621
1003817100381710038171003817Vℎ1003817100381710038171003817 forallV
ℎisin 119878
ℎ (81)
We note that the aforementioned definition (Vℎ 120578
ℎ)ℎmay
be used also for 120578ℎisin 119878
ℎand that (V
ℎ 119908
ℎ)ℎ= (V
ℎ 119868
lowast
ℎ119908
ℎ)ℎfor
Vℎ 119908
ℎisin 119878
ℎ
The lumpedmass method defined by (78) is equivalent to
(119906ℎ119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 119906
ℎ 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 119906ℎ(119904) 119868
lowast
ℎVℎ) 119889119904
= (119891 119868lowast
ℎVℎ) V
ℎisin 119878
ℎ
(82)
We introduce the quadrature error
120576ℎ(V
ℎ 119908
ℎ) = (V
ℎ 119908
ℎ)ℎminus (V
ℎ 119908
ℎ) (83)
Lemma 16 (see [21]) Let Vℎ 119908
ℎisin 119878
ℎ Then
1003816100381610038161003816120576ℎ (Vℎ 119908ℎ)1003816100381610038161003816 le 119862ℎ
2 1003817100381710038171003817nablaVℎ1003817100381710038171003817
1003817100381710038171003817nabla119908ℎ
1003817100381710038171003817 (84)
Theorem 17 Let 119906ℎand 119906 be the solutions of (82) and (2)
respectively and assume 119906ℎ(0) = 119877
ℎ1199060 Then we have for the
error in the lumped mass semidiscrete method for 119905 ge 0 thefollowing
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905)
1003817100381710038171003817 le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ 1199062 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (85)
Proof In order to estimate 120579 we write
(120579119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 120579 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎVℎ) 119889119904
= (119906ℎ119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 119906
ℎ 119868
lowast
ℎVℎ)
+ int
119905
0
119861 (119905 119904 119906ℎ(119904) 119868
lowast
ℎVℎ) 119889119904
minus ((119881ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus 119860 (119905 119881
ℎ119906 119868
lowast
ℎVℎ)
minus int
119905
0
119861 (119905 119904 119881ℎ119906 (119904) 119868
lowast
ℎVℎ) 119889119904
= (119891 119868lowast
ℎVℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus 119860 (119905 119906 119868
lowast
ℎVℎ)
minus int
119905
0
119861 (119905 119904 119906 (119904) 119868lowast
ℎVℎ)
= (119906119905 119868
lowast
ℎVℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)ℎ
= minus (120588119905 119868
lowast
ℎVℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)ℎ+ ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
(86)
We rewrite
((119881ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
= ((119881ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus ((119881
ℎ119906)
119905 V
ℎ)
+ ((119881ℎ119906)
119905 V
ℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
= 120576ℎ((119881
ℎ119906)
119905 V
ℎ) + ((119881
ℎ119906)
119905 V
ℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
(120579119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 120579 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎVℎ) 119889119904
= minus (120588119905 119868
lowast
ℎVℎ) + 120576
ℎ((119881
ℎ119906)
119905 V
ℎ)
+ ((119881ℎ119906)
119905 V
ℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
(87)
Setting Vℎ= 120579 in (87) we obtain
1
2
119889
119889119905120579
2
ℎ+ 119888
01205792
1
le1003817100381710038171003817120588119905
1003817100381710038171003817 120579 +1
21198880120579
2
1+ 119862int
119905
0
1205792
1119889119904
+ 120576ℎ((119881
ℎ119906)
119905 120579) + ((119881
ℎ119906)
119905 120579) minus ((119881
ℎ119906)
119905 119868
lowast
ℎ120579)
(88)
Using Lemma 16 and the inverse estimate we get1003816100381610038161003816120576ℎ (119881ℎ
119906119905 120579)
1003816100381610038161003816 le 119862ℎ2 1003817100381710038171003817nabla(119881ℎ
119906)119905
1003817100381710038171003817 nabla120579
le 119862ℎ2 1003817100381710038171003817nabla119906119905
1003817100381710038171003817 nabla120579
le 119862ℎ1003817100381710038171003817nabla119906119905
1003817100381710038171003817 120579
(89)
we have1003816100381610038161003816((119881ℎ
119906)119905 120579) minus ((119881
ℎ119906)
119905 119868
lowast
ℎ120579)1003816100381610038161003816 le 119862ℎ
1003817100381710038171003817nabla119906119905
1003817100381710038171003817 120579 (90)
Using Youngrsquos inequality and Gronwallrsquos lemma to eliminate120579
1on the right-hand side and using integration in 119905 we get
the result
1
2
119889
119889119905120579
2
ℎ+ 119888
0 120579 le1003817100381710038171003817120588119905
1003817100381710038171003817 120579 + 119862ℎ1003817100381710038171003817nabla119906119905
1003817100381710038171003817 120579 (91)
Using Youngrsquos inequality to eliminate 120579 on the right handside it becomes
Using integration in 119905 we get the result
We will now show that the 1198671-norm error bound of
theorem remains valid for the lumped mass method (82)
Theorem 18 Let 119906ℎand 119906 be the solutions of (82) and (2)
respectively and assume
119906ℎ(0) = 119877
ℎ1199060
10038171003817100381710038171199061ℎ(0) minus 119906
1
1003817100381710038171003817 le 119862ℎ210038171003817100381710038171199061
10038171003817100381710038172 (92)
Then we have for the error in the lumped mass semidiscretemethod for 119905 ge 0 the following
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905)
10038171003817100381710038171le 119862ℎ
2(10038171003817100381710038171199060
10038171003817100381710038172+10038171003817100381710038171199061
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904)
(93)
Journal of Mathematics 11
Proof Setting Vℎ= 120579
119905in (87) we obtain
10038171003817100381710038171205791199051003817100381710038171003817
2
ℎ+1
2
119889
119889119905119860 (119905 120579 119868
lowast
ℎ120579)
=1
2119860
119905(119905 120579 119868
lowast
ℎ120579) +
1
2[119860 (119905 120579
119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)]
119861 (119905 119905 120579 (119905) 119868lowast
ℎ120579 (119905)) + int
119905
0
119861119905(119905 119904 120579 (119904) 119868
lowast
ℎ120579 (119905)) 119889119904
minus119889
119889119905int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579 (119905)) 119889119904 minus (120588
119905 119868
lowast
ℎ120579119905)
minus 120576ℎ((119881
ℎ119906)
119905 120579
119905) + ((119881
ℎ119906)
119905 120579) minus ((119881
ℎ119906)
119905 119868
lowast
ℎ120579)
(94)
It follows thus that using integration in 119905 and Gronwallrsquoslemma we have
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
ℎ+ 120579
2
1le 119862nabla120579 (0)
2+ 119862int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
10038171003817100381710038171205791199051003817100381710038171003817 119889119904
+ 119862ℎ2int
119905
0
1003817100381710038171003817119906119905
1003817100381710038171003817
2
1119889119904
(95)
6 Full Discretization
Let 120597119880119899= (119880
119899minus119880
119899minus1)119896 be the backward difference quotient
of 119880119899 assume that 119860ℎ
= 119875ℎ119860 is a discrete analogue of 119860
(similarly 119861ℎ
= 119875ℎ119861) where 119875
ℎ 119871
2(Ω) rarr 119878
lowast
ℎthe 119871
2
projection is defined by
(119875ℎV 119868lowast
ℎVℎ) = (V 119868lowast
ℎVℎ) V isin 119871
2(Ω) V
ℎisin 119878
ℎ (96)
In order to define fully discrete approximation of (11) wediscretize the time by taking 119905
119899= 119899119896 119896 gt 0 119899 = 1 2 and
use the numerical quadrature
int
119905119899minus12
0
119892 (119904) 119889119904 asymp
119899
sum
119896=1
120596119899119896119892 (119905
119896minus12) 119905
119899minus12= (119899 minus
1
2) 119896
(97)
Here 120596119899119896 are the integrationweights andwe assume that
the following error estimate is valid
119902119899(119892) = int
119905119899minus12
0
119892 (119904) 119889119904minus
119899
sum
119896=1
120596119899119896119892 (119905
119896minus12)
le 1198621198962int
119905119899
0
(10038161003816100381610038161003816119892101584010038161003816100381610038161003816+100381610038161003816100381610038161198921015840101584010038161003816100381610038161003816) 119889119904
(98)
Now define our complete discrete FVE approximation of(11) by the following find 119880
119899isin 119878
ℎfor 119899 = 1 2 such that
for all Vℎisin 119878
ℎ
(120597119880119899 119868
lowast
ℎVℎ) + 119860 (119905
119899minus12 119880
119899minus12 119868
lowast
ℎVℎ)
+
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12 119880
119896minus12 119868
lowast
ℎVℎ)
= (119891119899minus12
119868lowast
ℎVℎ)
1198800 in 119878
ℎ
(99)
where 119880119899minus12= (119880
119899+ 119880
119899minus1)2
Theorem 19 Let 119906(119905) and 119880119899 be the solutions of problem (2)
and its complete discrete scheme (99) respectively Then forany 119879 gt 0 there exists a positive constant 119862 = 119862(119879) gt 0independent of ℎ such that for 0 lt 119905
119899le 119879
1003817100381710038171003817119906 (119905119899) minus 1198801198991003817100381710038171003817
le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905119899
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
+ 1198621198962(int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905119905
1003817100381710038171003817) 119889119904)
(100)
Proof Let us split the error into two parts 119906(119905119899) minus 119880
119899= 120588
119899+
120579119899 where 120588
119899= 119906(119905
119899)minus119881
ℎ119906(119905
119899) and 120579119899 = 119881
ℎ119906(119905
119899)minus119880
119899 and let119882 = 119881
ℎ119906(119905) isin 119878
ℎbe the Ritz-Volterra projection of 119906 Then
from (2) and (99) we have for all Vℎisin 119878
ℎthe following
(120597120579119899 119868
lowast
ℎVℎ) + 119860 (119905
119899minus12 120579
119899minus12 119868
lowast
ℎVℎ)
+
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12 120579
119896minus12 119868
lowast
ℎVℎ)
= minus (119903119899 119868
lowast
ℎVℎ) forallV
ℎisin 119878
ℎ
(101)
where
119903119899= 119903
1
119899+ 119903
2
119899+ 119903
3
119899+ 119903
4
119899
1199031
119899= 120597120588
119899
1199032
119899= 120597119906 (119905
119899) minus 119906
119905(119905
119899minus12)
1199033
119899= 119860(119905
119899minus12(119906 (119905
119899) + 119906 (119905
119899minus1))
2minus 119906 (119905
119899minus12))
1199034
119899= 119902
119899(119861
ℎ119882)
=
119899
sum
119896=1
120596119899119896119861ℎ(119905
119899minus12 119905
119896minus12119882
119896minus12 119868
lowast
ℎVℎ)
minus int
119905119899minus12
0
119861 (119905119899 119904119882 (119904) 119868
lowast
ℎVℎ) 119889119904
(102)
In fact by Taylor expansion
119906119899+1
= 119906119899+ 119896119906
1015840(119905
119899) + int
119905119899+1
119905119899
11990610158401015840(119904) (119905
119899+1minus 119904) 119889119904
= 119906119899+ 119896119906
1015840(119905
119899) +
1198962
211990610158401015840(119905
119899) +
1198963
6119906(3)
(119905119899)
+1
6int
119905119899+1
119905119899
119906(4)
(119904) (119905119899+1
minus 119904)3
119889119904
(103)
12 Journal of Mathematics
we have100381710038171003817100381710038171199031
119899
10038171003817100381710038171003817=
10038171003817100381710038171003817120597120588
11989910038171003817100381710038171003817le
1
119896int
119905119899
119905119899minus1
10038171003817100381710038171205881199051003817100381710038171003817 119889119904 le 119862
ℎ2
119896int
119905119899
119905119899minus1
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
100381710038171003817100381710038171199032
119899
10038171003817100381710038171003817=
10038171003817100381710038171003817120597119906 (119905
119899) minus 119906
119905(119905
119899minus12)10038171003817100381710038171003817
=1
119896
100381710038171003817100381710038171003817100381710038171003817
int
119905119899
119905119899minus1
(119906119905(119904) minus 119906
119905(119905
119899minus12)) 119889119904
100381710038171003817100381710038171003817100381710038171003817
le 119862119896int
119905119899
119905119899minus1
10038171003817100381710038171003817119906(3)
(119904)10038171003817100381710038171003817119889119904
100381710038171003817100381710038171199033
119899
10038171003817100381710038171003817=
100381710038171003817100381710038171003817100381710038171003817
119860(119905119899minus12
119906 (119905
119899) + 119906 (119905
119899minus1)
2minus 119906 (119905
119899minus12) 119868
lowast
ℎVℎ)
100381710038171003817100381710038171003817100381710038171003817
le 119862119896int
119905119899
119905119899minus1
1003817100381710038171003817119860119906119905119905(119904)
1003817100381710038171003817 119889119904 le 119862119896int
119905119899
119905119899minus1
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
(104)
In addition the quadrature error satisfies100381710038171003817100381710038171199034
119899
10038171003817100381710038171003817= 119902
119899minus12(119861
ℎ119882)
=
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12119882
119896minus12 119868
lowast
ℎVℎ)
minus int
119905119899minus12
0
119861 (119905119899 119904119882 (119904) 119868
lowast
ℎVℎ) 119889119904
le 1198621198962int
119905119899
0
1003817100381710038171003817(119861ℎ119882)
119904119904
1003817100381710038171003817 119889119904
le 1198621198962int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172) 119889119904
119896
119873
sum
119899=1
10038171003817100381710038171199031198991003817100381710038171003817 le 119862ℎ
2int
119905119899
0
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
+ 1198621198962int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172+10038171003817100381710038171003817119906(3)10038171003817100381710038171003817
) 119889119904
(105)
Taking Vℎ= 120579
119899minus12 in (101) and noting that (120597120579119899 119868lowastℎ120579119899minus12
) =
(12)120597|||120579119899|||
2 there is1003816100381610038161003816
1003816100381610038161003816
10038161003816100381610038161205791198991003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816
2
minus10038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus110038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
+ 211989611988810038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus1210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
1
le 1198621198962
119899
sum
119896=1
10038171003817100381710038171003817120579119896minus12100381710038171003817100381710038171
10038171003817100381710038171003817120579119899minus12100381710038171003817100381710038171
+ 1198621198961003817100381710038171003817119903119899
1003817100381710038171003817
10038171003817100381710038171003817120579119899minus1210038171003817100381710038171003817
le11989611988810038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus1210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
1+ 119862119896
2
119899
sum
119896=1
10038171003817100381710038171003817120579119896minus1210038171003817100381710038171003817
2
1+ 119862119896
10038171003817100381710038171199031198991003817100381710038171003817
10038171003817100381710038171003817120579119899minus1210038171003817100381710038171003817
(106)
Summing from 119899 = 1 to 119873 and then after cancelling thecommon factor and using Gronwallrsquos lemma we obtain
10038161003816100381610038161003816
10038161003816100381610038161003816
1003816100381610038161003816100381612057911987310038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
le 11986210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579010038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
+ 119862119896
119873
sum
119896=1
10038171003817100381710038171199031198991003817100381710038171003817 (
1003817100381710038171003817100381712057911989610038171003817100381710038171003817
+10038171003817100381710038171003817120579119896minus1210038171003817100381710038171003817
) (107)
and then
10038161003816100381610038161003816
10038161003816100381610038161003816
1003816100381610038161003816100381612057911987310038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816le 119862
10038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579010038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816+ 119862119896
119873
sum
119899=1
10038171003817100381710038171199031198991003817100381710038171003817
(108)
the theorem follows from the estimates of 120588119899 and 119903119899
References
[1] Z Q Cai ldquoOn the finite volume element methodrdquo NumerischeMathematik vol 58 no 7 pp 713ndash735 1991
[2] S H Chou and D Y Kwak ldquoAnalysis and convergence of aMAC-like scheme for the generalized Stokes problemrdquo Numer-ical Methods for Partial Differential Equations vol 13 no 2 pp147ndash162 1997
[3] P Chatzipantelidis ldquoA finite volume method based on theCrouzeix-Raviart element for elliptic PDErsquos in two dimensionsrdquoNumerische Mathematik vol 82 no 3 pp 409ndash432 1999
[4] P Chatzipantelidis ldquoFinite volumemethods for elliptic PDErsquos anew approachrdquo Mathematical Modelling and Numerical Analy-sis vol 36 no 2 pp 307ndash324 2002
[5] P Chatzipantelidis R D Lazarov and V Thomee ldquoErrorestimates for a finite volume element method for parabolicequations in convex polygonal domainsrdquoNumericalMethods forPartial Differential Equations vol 20 no 5 pp 650ndash674 2004
[6] R E Ewing R D Lazarov and Y Lin ldquoFinite volume elementapproximations of nonlocal in time one-dimensional flows inporous mediardquo Computing vol 64 no 2 pp 157ndash182 2000
[7] R Ewing R Lazarov and Y Lin ldquoFinite volume elementapproximations of nonlocal reactive flows in porous mediardquoNumericalMethods for Partial Differential Equations vol 16 no3 pp 285ndash311 2000
[8] R E Ewing T Lin andY Lin ldquoOn the accuracy of the finite vol-ume element method based on piecewise linear polynomialsrdquoSIAM Journal on Numerical Analysis vol 39 no 6 pp 1865ndash1888 2002
[9] R K Sinha and J Geiser ldquoError estimates for finite volumeelement methods for convection-diffusion-reaction equationsrdquoApplied Numerical Mathematics vol 57 no 1 pp 59ndash72 2007
[10] S H Chou ldquoAnalysis and convergence of a covolume methodfor the generalized Stokes problemrdquo Mathematics of Computa-tion vol 66 no 217 pp 85ndash104 1997
[11] M Berggren ldquoA vertex-centered dual discontinuous Galerkinmethodrdquo Journal of Computational and Applied Mathematicsvol 192 no 1 pp 175ndash181 2006
[12] S H Chou and D Y Kwak ldquoMultigrid algorithms for a vertex-centered covolume method for elliptic problemsrdquo NumerischeMathematik vol 90 no 3 pp 441ndash458 2002
[13] R Eymard T Gallouet and R Herbin Finite Volume MethodsHandbook of Numerical Analysis North-Holland AmsterdamThe Netherlands 2000
[14] V R Voller Basic Control Volume Finite Element Methods forFluids and Solids World Scientific Publishing 2009
[15] J Huang and S Xi ldquoOn the finite volume element method forgeneral self-adjoint elliptic problemsrdquo SIAM Journal on Numer-ical Analysis vol 35 no 5 pp 1762ndash1774 1998
[16] X Ma S Shu and A Zhou ldquoSymmetric finite volume discreti-zations for parabolic problemsrdquo Computer Methods in AppliedMechanics and Engineering vol 192 no 39-40 pp 4467ndash44852003
[17] R D Lazarov and S Z Tomov ldquoAdaptive finite volume elementmethod for convection-diffusion-reaction problems in 3-Drdquo inScientific Computing and Applications vol 7 of Advances inComputation Theory and Practice pp 91ndash106 Nova SciencePublishers Huntington NY USA 2001
[18] I DMishevFinite volume and finite volume elementmethods fornon-symmetric problems [PhD thesis] Texas AampM University1997 Technical Report ISC-96-04-MATH
Journal of Mathematics 13
[19] C Chen and T Shih Finite Element Methods for Integrodifferen-tial Equations World Scientific Publishing Singapore 1998
[20] Y P Lin V Thomee and L B Wahlbin ldquoRitz-Volterra pro-jections to finite-element spaces and applications to integrod-ifferential and related equationsrdquo SIAM Journal on NumericalAnalysis vol 28 no 4 pp 1047ndash1070 1991
[21] VThomeeGalerkin Finite Element Methods for Parabolic Prob-lems Springer Series in Computational Mathematics SpringerNew York NY USA 2006
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Differential EquationsInternational Journal of
Volume 2014
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Function Spaces
Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Algebra
Discrete Dynamics in Nature and Society
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Decision SciencesAdvances in
Discrete MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
Volume 2014 Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Stochastic AnalysisInternational Journal of
Journal of Mathematics 9
with1003817100381710038171003817120595
10038171003817100381710038171119902le100381710038171003817100381712059310038171003817100381710038170119902
((ℎminus 119906
ℎ)119909 120593)
= 119860 (119905 ℎminus 119906
ℎ 120595)
= 119860 (119905 ℎminus 119906
ℎ 120595 minus 119877
ℎ120595) + 119860 (119905 119906 minus 119906
ℎ 119877
ℎ120595)
minus 119860 (119905 119906 minus 119906ℎ 119868
lowast
ℎ119877ℎ120595) minus ((119906 minus 119906
ℎ)119905 119868
lowast
ℎ119877ℎ120595)
minus int
119905
0
119861 (119905 119904 (119906 minus 119906ℎ) (119904) 119868
lowast
ℎ119877ℎ120595) 119889119904
+ 119860 (119905 ℎminus 119906 119877
ℎ120595)
= [119860 (119905 119906 minus 119906ℎ 119877
ℎ120595) minus 119860 (119905 119906 minus 119906
ℎ 119868
lowast
ℎ119877ℎ120595)]
minus ((119906 minus 119906ℎ)119905 119868
lowast
ℎ119877ℎ120595) minus ((
ℎminus 119906)
119905 119877
ℎ120595)
minus int
119905
0
119861 (119905 119904 (119906 minus 119906ℎ) (119904) 119868
lowast
ℎ119877ℎ120595) 119889119904
minus int
119905
0
119861 (119905 119904 (ℎminus 119906) (119904) 119877
ℎ120595) 119889119904
= 1198681+ 119868
2+ 119868
3
(71)
On the other hand10038161003816100381610038161198681
1003816100381610038161003816 le 119862ℎ1003817100381710038171003817119906 minus 119906
ℎ
10038171003817100381710038171119901
100381710038171003817100381712059510038171003817100381710038171119902
100381610038161003816100381611986821003816100381610038161003816 le 119862 (
1003817100381710038171003817(119906 minus 119906ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817)1003817100381710038171003817120595
1003817100381710038171003817
le 119862 (1003817100381710038171003817(119906 minus 119906
ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817)1003817100381710038171003817120595
10038171003817100381710038171119902
(72)
where we have used the fact 120595 le 1205951119903 119903 gt 1
100381610038161003816100381611986831003816100381610038161003816 le int
119905
0
(1003817100381710038171003817(119906 minus 119906
ℎ) (119904)
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus
ℎ) (119904)
10038171003817100381710038171119901) 119889119904
100381710038171003817100381712059510038171003817100381710038171119902
1003817100381710038171003817(ℎminus 119906
ℎ)119909
10038171003817100381710038170119901
= sup120593isinCinfin0
((ℎminus 119906
ℎ)119909 120593)
100381710038171003817100381712059310038171003817100381710038170119902
le 119862(
ℎ1003817100381710038171003817119906 minus 119906
ℎ
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus 119906
ℎ)119905
1003817100381710038171003817 +1003817100381710038171003817(ℎ
minus 119906)119905
1003817100381710038171003817
+int
119905
0
(1003817100381710038171003817(119906 minus 119906
ℎ) (119904)
10038171003817100381710038171119901+1003817100381710038171003817(119906 minus
ℎ) (119904)
10038171003817100381710038171119901) 119889119904
)
(73)
We deduce the result from the known finite element esti-mates
Remark 15 In order to estimate (119906 minus 119906ℎ)119905 by differentiating
(42) with respect to 119905 we obtain
(120579119905119905 119868
lowast
ℎVℎ) + 119860 (119905 120579
119905 119868
lowast
ℎVℎ) + 119860
119905(119905 120579
119905 119868
lowast
ℎVℎ)
+ 119861 (119905 119905 120579 119868lowast
ℎVℎ) + int
119905
0
119861119905(119905 119904 120579 (119904) 119868
lowast
ℎVℎ) 119889119904
= minus (120588119905119905 119868
lowast
ℎVℎ)
(74)
Setting Vℎ= 120579
119905 we obtain
1
2
119889
119889119905
1003816100381610038161003816
1003816100381610038161003816
10038161003816100381610038161205791199051003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816
2
+ 1198881003817100381710038171003817120579119905
1003817100381710038171003817
2
1le1003817100381710038171003817120588119905119905
1003817100381710038171003817
10038171003817100381710038171205791199051003817100381710038171003817
+1
21198881003817100381710038171003817120579119905
1003817100381710038171003817
2
1+ 119862120579
2
1+ int
119905
0
1205792
1119889119904
le1003817100381710038171003817120588119905119905
1003817100381710038171003817
10038171003817100381710038171205791199051003817100381710038171003817 +
1
21198881003817100381710038171003817120579119905
1003817100381710038171003817
2
1+ 119862int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
1119889119904
(75)
Using kickback argument integrating and applying Gron-wallrsquos lemma we deduce
10038171003817100381710038171205791199051003817100381710038171003817 le 119862(
1003817100381710038171003817120579119905 (0)1003817100381710038171003817 + int
119905
0
100381710038171003817100381712058811990511990510038171003817100381710038171119889119904)
le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+10038171003817100381710038171199061
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904)
(76)
5 The Lumped Mass Finite VolumeElement Method
In this section we restrict our study to the 2D case A simpleway to define the lumped mass scheme [21] is to replace themass matrix 119872
ℎin (14) by the diagonal matrix 119872
ℎobtained
by taking for its diagonal elements the numbers 119872ℎ119894119894
=
sum119873ℎ
119895=1119872
ℎ119894119895or by lumping all masses in one row into the
diagonal entryThismakes the inversion of thematrix in frontof1205721015840
(119905) a trivialityWewill therefore study thematrix problem
119872ℎ1205721015840(119905) + 119860
ℎ(119905) 120572 (119905) + int
119905
0
119861ℎ(119905 119904) 120572 (119904) 119889119904 = 119865
ℎ(119905) (77)
We know that the lumped mass method defined by (77)above is equivalent to
(119868lowast
ℎ119906ℎ119905 119868
lowast
ℎVℎ) + 119860 (119905 119906
ℎ 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 119906ℎ(119904) 119868
lowast
ℎVℎ) 119889119904
= (119891 119868lowast
ℎVℎ) V
ℎisin 119878
ℎ
(78)
Our alternative interpretation of this procedure will beto think of (77) as being obtained by evaluating the firstterm in (78) by numerical quadrature Let 119870 be a triangle ofthe triangulation 119879
ℎ let 119909
119895 119895 = 1 2 3 be its vertices and
consider the quadrature formula
119876119870ℎ
(119891) =1
3area119870
3
sum
119895=1
119891 (119909119895) ≃ int
119870
119891119889119909 (79)
We may then define the associated bilinear form in 119878ℎtimes
119878lowast
ℎ using the quadrature scheme by the following
(Vℎ 120578
ℎ)ℎ= sum
119870isin119879ℎ
119876119870ℎ
(Vℎ120578ℎ) = sum
119909119894isin119873119886
ℎ
Vℎ(119909
119894) 120578
ℎ(119909
119894)10038161003816100381610038161003816119881119909119894
10038161003816100381610038161003816
forallVℎisin 119878
ℎ 120578
ℎisin 119878
lowast
ℎ
(80)
10 Journal of Mathematics
We note that Vℎ2
ℎ= (V
ℎ 119868
lowast
ℎVℎ)ℎis a norm in 119878
ℎwhich is
equivalent to the 1198712-norm uniformly in ℎ that is there existtwo positive constants 119862
1and 119862
2such that for all V
ℎisin 119878
ℎ we
have
1198620
1003817100381710038171003817Vℎ1003817100381710038171003817 le
1003817100381710038171003817Vℎ1003817100381710038171003817ℎ
le 1198621
1003817100381710038171003817Vℎ1003817100381710038171003817 forallV
ℎisin 119878
ℎ (81)
We note that the aforementioned definition (Vℎ 120578
ℎ)ℎmay
be used also for 120578ℎisin 119878
ℎand that (V
ℎ 119908
ℎ)ℎ= (V
ℎ 119868
lowast
ℎ119908
ℎ)ℎfor
Vℎ 119908
ℎisin 119878
ℎ
The lumpedmass method defined by (78) is equivalent to
(119906ℎ119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 119906
ℎ 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 119906ℎ(119904) 119868
lowast
ℎVℎ) 119889119904
= (119891 119868lowast
ℎVℎ) V
ℎisin 119878
ℎ
(82)
We introduce the quadrature error
120576ℎ(V
ℎ 119908
ℎ) = (V
ℎ 119908
ℎ)ℎminus (V
ℎ 119908
ℎ) (83)
Lemma 16 (see [21]) Let Vℎ 119908
ℎisin 119878
ℎ Then
1003816100381610038161003816120576ℎ (Vℎ 119908ℎ)1003816100381610038161003816 le 119862ℎ
2 1003817100381710038171003817nablaVℎ1003817100381710038171003817
1003817100381710038171003817nabla119908ℎ
1003817100381710038171003817 (84)
Theorem 17 Let 119906ℎand 119906 be the solutions of (82) and (2)
respectively and assume 119906ℎ(0) = 119877
ℎ1199060 Then we have for the
error in the lumped mass semidiscrete method for 119905 ge 0 thefollowing
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905)
1003817100381710038171003817 le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ 1199062 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (85)
Proof In order to estimate 120579 we write
(120579119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 120579 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎVℎ) 119889119904
= (119906ℎ119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 119906
ℎ 119868
lowast
ℎVℎ)
+ int
119905
0
119861 (119905 119904 119906ℎ(119904) 119868
lowast
ℎVℎ) 119889119904
minus ((119881ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus 119860 (119905 119881
ℎ119906 119868
lowast
ℎVℎ)
minus int
119905
0
119861 (119905 119904 119881ℎ119906 (119904) 119868
lowast
ℎVℎ) 119889119904
= (119891 119868lowast
ℎVℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus 119860 (119905 119906 119868
lowast
ℎVℎ)
minus int
119905
0
119861 (119905 119904 119906 (119904) 119868lowast
ℎVℎ)
= (119906119905 119868
lowast
ℎVℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)ℎ
= minus (120588119905 119868
lowast
ℎVℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)ℎ+ ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
(86)
We rewrite
((119881ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
= ((119881ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus ((119881
ℎ119906)
119905 V
ℎ)
+ ((119881ℎ119906)
119905 V
ℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
= 120576ℎ((119881
ℎ119906)
119905 V
ℎ) + ((119881
ℎ119906)
119905 V
ℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
(120579119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 120579 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎVℎ) 119889119904
= minus (120588119905 119868
lowast
ℎVℎ) + 120576
ℎ((119881
ℎ119906)
119905 V
ℎ)
+ ((119881ℎ119906)
119905 V
ℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
(87)
Setting Vℎ= 120579 in (87) we obtain
1
2
119889
119889119905120579
2
ℎ+ 119888
01205792
1
le1003817100381710038171003817120588119905
1003817100381710038171003817 120579 +1
21198880120579
2
1+ 119862int
119905
0
1205792
1119889119904
+ 120576ℎ((119881
ℎ119906)
119905 120579) + ((119881
ℎ119906)
119905 120579) minus ((119881
ℎ119906)
119905 119868
lowast
ℎ120579)
(88)
Using Lemma 16 and the inverse estimate we get1003816100381610038161003816120576ℎ (119881ℎ
119906119905 120579)
1003816100381610038161003816 le 119862ℎ2 1003817100381710038171003817nabla(119881ℎ
119906)119905
1003817100381710038171003817 nabla120579
le 119862ℎ2 1003817100381710038171003817nabla119906119905
1003817100381710038171003817 nabla120579
le 119862ℎ1003817100381710038171003817nabla119906119905
1003817100381710038171003817 120579
(89)
we have1003816100381610038161003816((119881ℎ
119906)119905 120579) minus ((119881
ℎ119906)
119905 119868
lowast
ℎ120579)1003816100381610038161003816 le 119862ℎ
1003817100381710038171003817nabla119906119905
1003817100381710038171003817 120579 (90)
Using Youngrsquos inequality and Gronwallrsquos lemma to eliminate120579
1on the right-hand side and using integration in 119905 we get
the result
1
2
119889
119889119905120579
2
ℎ+ 119888
0 120579 le1003817100381710038171003817120588119905
1003817100381710038171003817 120579 + 119862ℎ1003817100381710038171003817nabla119906119905
1003817100381710038171003817 120579 (91)
Using Youngrsquos inequality to eliminate 120579 on the right handside it becomes
Using integration in 119905 we get the result
We will now show that the 1198671-norm error bound of
theorem remains valid for the lumped mass method (82)
Theorem 18 Let 119906ℎand 119906 be the solutions of (82) and (2)
respectively and assume
119906ℎ(0) = 119877
ℎ1199060
10038171003817100381710038171199061ℎ(0) minus 119906
1
1003817100381710038171003817 le 119862ℎ210038171003817100381710038171199061
10038171003817100381710038172 (92)
Then we have for the error in the lumped mass semidiscretemethod for 119905 ge 0 the following
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905)
10038171003817100381710038171le 119862ℎ
2(10038171003817100381710038171199060
10038171003817100381710038172+10038171003817100381710038171199061
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904)
(93)
Journal of Mathematics 11
Proof Setting Vℎ= 120579
119905in (87) we obtain
10038171003817100381710038171205791199051003817100381710038171003817
2
ℎ+1
2
119889
119889119905119860 (119905 120579 119868
lowast
ℎ120579)
=1
2119860
119905(119905 120579 119868
lowast
ℎ120579) +
1
2[119860 (119905 120579
119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)]
119861 (119905 119905 120579 (119905) 119868lowast
ℎ120579 (119905)) + int
119905
0
119861119905(119905 119904 120579 (119904) 119868
lowast
ℎ120579 (119905)) 119889119904
minus119889
119889119905int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579 (119905)) 119889119904 minus (120588
119905 119868
lowast
ℎ120579119905)
minus 120576ℎ((119881
ℎ119906)
119905 120579
119905) + ((119881
ℎ119906)
119905 120579) minus ((119881
ℎ119906)
119905 119868
lowast
ℎ120579)
(94)
It follows thus that using integration in 119905 and Gronwallrsquoslemma we have
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
ℎ+ 120579
2
1le 119862nabla120579 (0)
2+ 119862int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
10038171003817100381710038171205791199051003817100381710038171003817 119889119904
+ 119862ℎ2int
119905
0
1003817100381710038171003817119906119905
1003817100381710038171003817
2
1119889119904
(95)
6 Full Discretization
Let 120597119880119899= (119880
119899minus119880
119899minus1)119896 be the backward difference quotient
of 119880119899 assume that 119860ℎ
= 119875ℎ119860 is a discrete analogue of 119860
(similarly 119861ℎ
= 119875ℎ119861) where 119875
ℎ 119871
2(Ω) rarr 119878
lowast
ℎthe 119871
2
projection is defined by
(119875ℎV 119868lowast
ℎVℎ) = (V 119868lowast
ℎVℎ) V isin 119871
2(Ω) V
ℎisin 119878
ℎ (96)
In order to define fully discrete approximation of (11) wediscretize the time by taking 119905
119899= 119899119896 119896 gt 0 119899 = 1 2 and
use the numerical quadrature
int
119905119899minus12
0
119892 (119904) 119889119904 asymp
119899
sum
119896=1
120596119899119896119892 (119905
119896minus12) 119905
119899minus12= (119899 minus
1
2) 119896
(97)
Here 120596119899119896 are the integrationweights andwe assume that
the following error estimate is valid
119902119899(119892) = int
119905119899minus12
0
119892 (119904) 119889119904minus
119899
sum
119896=1
120596119899119896119892 (119905
119896minus12)
le 1198621198962int
119905119899
0
(10038161003816100381610038161003816119892101584010038161003816100381610038161003816+100381610038161003816100381610038161198921015840101584010038161003816100381610038161003816) 119889119904
(98)
Now define our complete discrete FVE approximation of(11) by the following find 119880
119899isin 119878
ℎfor 119899 = 1 2 such that
for all Vℎisin 119878
ℎ
(120597119880119899 119868
lowast
ℎVℎ) + 119860 (119905
119899minus12 119880
119899minus12 119868
lowast
ℎVℎ)
+
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12 119880
119896minus12 119868
lowast
ℎVℎ)
= (119891119899minus12
119868lowast
ℎVℎ)
1198800 in 119878
ℎ
(99)
where 119880119899minus12= (119880
119899+ 119880
119899minus1)2
Theorem 19 Let 119906(119905) and 119880119899 be the solutions of problem (2)
and its complete discrete scheme (99) respectively Then forany 119879 gt 0 there exists a positive constant 119862 = 119862(119879) gt 0independent of ℎ such that for 0 lt 119905
119899le 119879
1003817100381710038171003817119906 (119905119899) minus 1198801198991003817100381710038171003817
le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905119899
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
+ 1198621198962(int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905119905
1003817100381710038171003817) 119889119904)
(100)
Proof Let us split the error into two parts 119906(119905119899) minus 119880
119899= 120588
119899+
120579119899 where 120588
119899= 119906(119905
119899)minus119881
ℎ119906(119905
119899) and 120579119899 = 119881
ℎ119906(119905
119899)minus119880
119899 and let119882 = 119881
ℎ119906(119905) isin 119878
ℎbe the Ritz-Volterra projection of 119906 Then
from (2) and (99) we have for all Vℎisin 119878
ℎthe following
(120597120579119899 119868
lowast
ℎVℎ) + 119860 (119905
119899minus12 120579
119899minus12 119868
lowast
ℎVℎ)
+
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12 120579
119896minus12 119868
lowast
ℎVℎ)
= minus (119903119899 119868
lowast
ℎVℎ) forallV
ℎisin 119878
ℎ
(101)
where
119903119899= 119903
1
119899+ 119903
2
119899+ 119903
3
119899+ 119903
4
119899
1199031
119899= 120597120588
119899
1199032
119899= 120597119906 (119905
119899) minus 119906
119905(119905
119899minus12)
1199033
119899= 119860(119905
119899minus12(119906 (119905
119899) + 119906 (119905
119899minus1))
2minus 119906 (119905
119899minus12))
1199034
119899= 119902
119899(119861
ℎ119882)
=
119899
sum
119896=1
120596119899119896119861ℎ(119905
119899minus12 119905
119896minus12119882
119896minus12 119868
lowast
ℎVℎ)
minus int
119905119899minus12
0
119861 (119905119899 119904119882 (119904) 119868
lowast
ℎVℎ) 119889119904
(102)
In fact by Taylor expansion
119906119899+1
= 119906119899+ 119896119906
1015840(119905
119899) + int
119905119899+1
119905119899
11990610158401015840(119904) (119905
119899+1minus 119904) 119889119904
= 119906119899+ 119896119906
1015840(119905
119899) +
1198962
211990610158401015840(119905
119899) +
1198963
6119906(3)
(119905119899)
+1
6int
119905119899+1
119905119899
119906(4)
(119904) (119905119899+1
minus 119904)3
119889119904
(103)
12 Journal of Mathematics
we have100381710038171003817100381710038171199031
119899
10038171003817100381710038171003817=
10038171003817100381710038171003817120597120588
11989910038171003817100381710038171003817le
1
119896int
119905119899
119905119899minus1
10038171003817100381710038171205881199051003817100381710038171003817 119889119904 le 119862
ℎ2
119896int
119905119899
119905119899minus1
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
100381710038171003817100381710038171199032
119899
10038171003817100381710038171003817=
10038171003817100381710038171003817120597119906 (119905
119899) minus 119906
119905(119905
119899minus12)10038171003817100381710038171003817
=1
119896
100381710038171003817100381710038171003817100381710038171003817
int
119905119899
119905119899minus1
(119906119905(119904) minus 119906
119905(119905
119899minus12)) 119889119904
100381710038171003817100381710038171003817100381710038171003817
le 119862119896int
119905119899
119905119899minus1
10038171003817100381710038171003817119906(3)
(119904)10038171003817100381710038171003817119889119904
100381710038171003817100381710038171199033
119899
10038171003817100381710038171003817=
100381710038171003817100381710038171003817100381710038171003817
119860(119905119899minus12
119906 (119905
119899) + 119906 (119905
119899minus1)
2minus 119906 (119905
119899minus12) 119868
lowast
ℎVℎ)
100381710038171003817100381710038171003817100381710038171003817
le 119862119896int
119905119899
119905119899minus1
1003817100381710038171003817119860119906119905119905(119904)
1003817100381710038171003817 119889119904 le 119862119896int
119905119899
119905119899minus1
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
(104)
In addition the quadrature error satisfies100381710038171003817100381710038171199034
119899
10038171003817100381710038171003817= 119902
119899minus12(119861
ℎ119882)
=
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12119882
119896minus12 119868
lowast
ℎVℎ)
minus int
119905119899minus12
0
119861 (119905119899 119904119882 (119904) 119868
lowast
ℎVℎ) 119889119904
le 1198621198962int
119905119899
0
1003817100381710038171003817(119861ℎ119882)
119904119904
1003817100381710038171003817 119889119904
le 1198621198962int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172) 119889119904
119896
119873
sum
119899=1
10038171003817100381710038171199031198991003817100381710038171003817 le 119862ℎ
2int
119905119899
0
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
+ 1198621198962int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172+10038171003817100381710038171003817119906(3)10038171003817100381710038171003817
) 119889119904
(105)
Taking Vℎ= 120579
119899minus12 in (101) and noting that (120597120579119899 119868lowastℎ120579119899minus12
) =
(12)120597|||120579119899|||
2 there is1003816100381610038161003816
1003816100381610038161003816
10038161003816100381610038161205791198991003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816
2
minus10038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus110038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
+ 211989611988810038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus1210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
1
le 1198621198962
119899
sum
119896=1
10038171003817100381710038171003817120579119896minus12100381710038171003817100381710038171
10038171003817100381710038171003817120579119899minus12100381710038171003817100381710038171
+ 1198621198961003817100381710038171003817119903119899
1003817100381710038171003817
10038171003817100381710038171003817120579119899minus1210038171003817100381710038171003817
le11989611988810038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus1210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
1+ 119862119896
2
119899
sum
119896=1
10038171003817100381710038171003817120579119896minus1210038171003817100381710038171003817
2
1+ 119862119896
10038171003817100381710038171199031198991003817100381710038171003817
10038171003817100381710038171003817120579119899minus1210038171003817100381710038171003817
(106)
Summing from 119899 = 1 to 119873 and then after cancelling thecommon factor and using Gronwallrsquos lemma we obtain
10038161003816100381610038161003816
10038161003816100381610038161003816
1003816100381610038161003816100381612057911987310038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
le 11986210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579010038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
+ 119862119896
119873
sum
119896=1
10038171003817100381710038171199031198991003817100381710038171003817 (
1003817100381710038171003817100381712057911989610038171003817100381710038171003817
+10038171003817100381710038171003817120579119896minus1210038171003817100381710038171003817
) (107)
and then
10038161003816100381610038161003816
10038161003816100381610038161003816
1003816100381610038161003816100381612057911987310038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816le 119862
10038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579010038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816+ 119862119896
119873
sum
119899=1
10038171003817100381710038171199031198991003817100381710038171003817
(108)
the theorem follows from the estimates of 120588119899 and 119903119899
References
[1] Z Q Cai ldquoOn the finite volume element methodrdquo NumerischeMathematik vol 58 no 7 pp 713ndash735 1991
[2] S H Chou and D Y Kwak ldquoAnalysis and convergence of aMAC-like scheme for the generalized Stokes problemrdquo Numer-ical Methods for Partial Differential Equations vol 13 no 2 pp147ndash162 1997
[3] P Chatzipantelidis ldquoA finite volume method based on theCrouzeix-Raviart element for elliptic PDErsquos in two dimensionsrdquoNumerische Mathematik vol 82 no 3 pp 409ndash432 1999
[4] P Chatzipantelidis ldquoFinite volumemethods for elliptic PDErsquos anew approachrdquo Mathematical Modelling and Numerical Analy-sis vol 36 no 2 pp 307ndash324 2002
[5] P Chatzipantelidis R D Lazarov and V Thomee ldquoErrorestimates for a finite volume element method for parabolicequations in convex polygonal domainsrdquoNumericalMethods forPartial Differential Equations vol 20 no 5 pp 650ndash674 2004
[6] R E Ewing R D Lazarov and Y Lin ldquoFinite volume elementapproximations of nonlocal in time one-dimensional flows inporous mediardquo Computing vol 64 no 2 pp 157ndash182 2000
[7] R Ewing R Lazarov and Y Lin ldquoFinite volume elementapproximations of nonlocal reactive flows in porous mediardquoNumericalMethods for Partial Differential Equations vol 16 no3 pp 285ndash311 2000
[8] R E Ewing T Lin andY Lin ldquoOn the accuracy of the finite vol-ume element method based on piecewise linear polynomialsrdquoSIAM Journal on Numerical Analysis vol 39 no 6 pp 1865ndash1888 2002
[9] R K Sinha and J Geiser ldquoError estimates for finite volumeelement methods for convection-diffusion-reaction equationsrdquoApplied Numerical Mathematics vol 57 no 1 pp 59ndash72 2007
[10] S H Chou ldquoAnalysis and convergence of a covolume methodfor the generalized Stokes problemrdquo Mathematics of Computa-tion vol 66 no 217 pp 85ndash104 1997
[11] M Berggren ldquoA vertex-centered dual discontinuous Galerkinmethodrdquo Journal of Computational and Applied Mathematicsvol 192 no 1 pp 175ndash181 2006
[12] S H Chou and D Y Kwak ldquoMultigrid algorithms for a vertex-centered covolume method for elliptic problemsrdquo NumerischeMathematik vol 90 no 3 pp 441ndash458 2002
[13] R Eymard T Gallouet and R Herbin Finite Volume MethodsHandbook of Numerical Analysis North-Holland AmsterdamThe Netherlands 2000
[14] V R Voller Basic Control Volume Finite Element Methods forFluids and Solids World Scientific Publishing 2009
[15] J Huang and S Xi ldquoOn the finite volume element method forgeneral self-adjoint elliptic problemsrdquo SIAM Journal on Numer-ical Analysis vol 35 no 5 pp 1762ndash1774 1998
[16] X Ma S Shu and A Zhou ldquoSymmetric finite volume discreti-zations for parabolic problemsrdquo Computer Methods in AppliedMechanics and Engineering vol 192 no 39-40 pp 4467ndash44852003
[17] R D Lazarov and S Z Tomov ldquoAdaptive finite volume elementmethod for convection-diffusion-reaction problems in 3-Drdquo inScientific Computing and Applications vol 7 of Advances inComputation Theory and Practice pp 91ndash106 Nova SciencePublishers Huntington NY USA 2001
[18] I DMishevFinite volume and finite volume elementmethods fornon-symmetric problems [PhD thesis] Texas AampM University1997 Technical Report ISC-96-04-MATH
Journal of Mathematics 13
[19] C Chen and T Shih Finite Element Methods for Integrodifferen-tial Equations World Scientific Publishing Singapore 1998
[20] Y P Lin V Thomee and L B Wahlbin ldquoRitz-Volterra pro-jections to finite-element spaces and applications to integrod-ifferential and related equationsrdquo SIAM Journal on NumericalAnalysis vol 28 no 4 pp 1047ndash1070 1991
[21] VThomeeGalerkin Finite Element Methods for Parabolic Prob-lems Springer Series in Computational Mathematics SpringerNew York NY USA 2006
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical Problems in Engineering
Hindawi Publishing Corporationhttpwwwhindawicom
Differential EquationsInternational Journal of
Volume 2014
Applied MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Probability and StatisticsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical PhysicsAdvances in
Complex AnalysisJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
OptimizationJournal of
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CombinatoricsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Operations ResearchAdvances in
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Function Spaces
Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of Mathematics and Mathematical Sciences
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Algebra
Discrete Dynamics in Nature and Society
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Decision SciencesAdvances in
Discrete MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
Volume 2014 Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Stochastic AnalysisInternational Journal of
10 Journal of Mathematics
We note that Vℎ2
ℎ= (V
ℎ 119868
lowast
ℎVℎ)ℎis a norm in 119878
ℎwhich is
equivalent to the 1198712-norm uniformly in ℎ that is there existtwo positive constants 119862
1and 119862
2such that for all V
ℎisin 119878
ℎ we
have
1198620
1003817100381710038171003817Vℎ1003817100381710038171003817 le
1003817100381710038171003817Vℎ1003817100381710038171003817ℎ
le 1198621
1003817100381710038171003817Vℎ1003817100381710038171003817 forallV
ℎisin 119878
ℎ (81)
We note that the aforementioned definition (Vℎ 120578
ℎ)ℎmay
be used also for 120578ℎisin 119878
ℎand that (V
ℎ 119908
ℎ)ℎ= (V
ℎ 119868
lowast
ℎ119908
ℎ)ℎfor
Vℎ 119908
ℎisin 119878
ℎ
The lumpedmass method defined by (78) is equivalent to
(119906ℎ119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 119906
ℎ 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 119906ℎ(119904) 119868
lowast
ℎVℎ) 119889119904
= (119891 119868lowast
ℎVℎ) V
ℎisin 119878
ℎ
(82)
We introduce the quadrature error
120576ℎ(V
ℎ 119908
ℎ) = (V
ℎ 119908
ℎ)ℎminus (V
ℎ 119908
ℎ) (83)
Lemma 16 (see [21]) Let Vℎ 119908
ℎisin 119878
ℎ Then
1003816100381610038161003816120576ℎ (Vℎ 119908ℎ)1003816100381610038161003816 le 119862ℎ
2 1003817100381710038171003817nablaVℎ1003817100381710038171003817
1003817100381710038171003817nabla119908ℎ
1003817100381710038171003817 (84)
Theorem 17 Let 119906ℎand 119906 be the solutions of (82) and (2)
respectively and assume 119906ℎ(0) = 119877
ℎ1199060 Then we have for the
error in the lumped mass semidiscrete method for 119905 ge 0 thefollowing
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905)
1003817100381710038171003817 le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ 1199062 + int
119905
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904) (85)
Proof In order to estimate 120579 we write
(120579119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 120579 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎVℎ) 119889119904
= (119906ℎ119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 119906
ℎ 119868
lowast
ℎVℎ)
+ int
119905
0
119861 (119905 119904 119906ℎ(119904) 119868
lowast
ℎVℎ) 119889119904
minus ((119881ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus 119860 (119905 119881
ℎ119906 119868
lowast
ℎVℎ)
minus int
119905
0
119861 (119905 119904 119881ℎ119906 (119904) 119868
lowast
ℎVℎ) 119889119904
= (119891 119868lowast
ℎVℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus 119860 (119905 119906 119868
lowast
ℎVℎ)
minus int
119905
0
119861 (119905 119904 119906 (119904) 119868lowast
ℎVℎ)
= (119906119905 119868
lowast
ℎVℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)ℎ
= minus (120588119905 119868
lowast
ℎVℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)ℎ+ ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
(86)
We rewrite
((119881ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
= ((119881ℎ119906)
119905 119868
lowast
ℎVℎ)ℎminus ((119881
ℎ119906)
119905 V
ℎ)
+ ((119881ℎ119906)
119905 V
ℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
= 120576ℎ((119881
ℎ119906)
119905 V
ℎ) + ((119881
ℎ119906)
119905 V
ℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
(120579119905 119868
lowast
ℎVℎ)ℎ+ 119860 (119905 120579 119868
lowast
ℎVℎ) + int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎVℎ) 119889119904
= minus (120588119905 119868
lowast
ℎVℎ) + 120576
ℎ((119881
ℎ119906)
119905 V
ℎ)
+ ((119881ℎ119906)
119905 V
ℎ) minus ((119881
ℎ119906)
119905 119868
lowast
ℎVℎ)
(87)
Setting Vℎ= 120579 in (87) we obtain
1
2
119889
119889119905120579
2
ℎ+ 119888
01205792
1
le1003817100381710038171003817120588119905
1003817100381710038171003817 120579 +1
21198880120579
2
1+ 119862int
119905
0
1205792
1119889119904
+ 120576ℎ((119881
ℎ119906)
119905 120579) + ((119881
ℎ119906)
119905 120579) minus ((119881
ℎ119906)
119905 119868
lowast
ℎ120579)
(88)
Using Lemma 16 and the inverse estimate we get1003816100381610038161003816120576ℎ (119881ℎ
119906119905 120579)
1003816100381610038161003816 le 119862ℎ2 1003817100381710038171003817nabla(119881ℎ
119906)119905
1003817100381710038171003817 nabla120579
le 119862ℎ2 1003817100381710038171003817nabla119906119905
1003817100381710038171003817 nabla120579
le 119862ℎ1003817100381710038171003817nabla119906119905
1003817100381710038171003817 120579
(89)
we have1003816100381610038161003816((119881ℎ
119906)119905 120579) minus ((119881
ℎ119906)
119905 119868
lowast
ℎ120579)1003816100381610038161003816 le 119862ℎ
1003817100381710038171003817nabla119906119905
1003817100381710038171003817 120579 (90)
Using Youngrsquos inequality and Gronwallrsquos lemma to eliminate120579
1on the right-hand side and using integration in 119905 we get
the result
1
2
119889
119889119905120579
2
ℎ+ 119888
0 120579 le1003817100381710038171003817120588119905
1003817100381710038171003817 120579 + 119862ℎ1003817100381710038171003817nabla119906119905
1003817100381710038171003817 120579 (91)
Using Youngrsquos inequality to eliminate 120579 on the right handside it becomes
Using integration in 119905 we get the result
We will now show that the 1198671-norm error bound of
theorem remains valid for the lumped mass method (82)
Theorem 18 Let 119906ℎand 119906 be the solutions of (82) and (2)
respectively and assume
119906ℎ(0) = 119877
ℎ1199060
10038171003817100381710038171199061ℎ(0) minus 119906
1
1003817100381710038171003817 le 119862ℎ210038171003817100381710038171199061
10038171003817100381710038172 (92)
Then we have for the error in the lumped mass semidiscretemethod for 119905 ge 0 the following
1003817100381710038171003817119906ℎ(119905) minus 119906 (119905)
10038171003817100381710038171le 119862ℎ
2(10038171003817100381710038171199060
10038171003817100381710038172+10038171003817100381710038171199061
10038171003817100381710038172+ int
119905
0
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904)
(93)
Journal of Mathematics 11
Proof Setting Vℎ= 120579
119905in (87) we obtain
10038171003817100381710038171205791199051003817100381710038171003817
2
ℎ+1
2
119889
119889119905119860 (119905 120579 119868
lowast
ℎ120579)
=1
2119860
119905(119905 120579 119868
lowast
ℎ120579) +
1
2[119860 (119905 120579
119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)]
119861 (119905 119905 120579 (119905) 119868lowast
ℎ120579 (119905)) + int
119905
0
119861119905(119905 119904 120579 (119904) 119868
lowast
ℎ120579 (119905)) 119889119904
minus119889
119889119905int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579 (119905)) 119889119904 minus (120588
119905 119868
lowast
ℎ120579119905)
minus 120576ℎ((119881
ℎ119906)
119905 120579
119905) + ((119881
ℎ119906)
119905 120579) minus ((119881
ℎ119906)
119905 119868
lowast
ℎ120579)
(94)
It follows thus that using integration in 119905 and Gronwallrsquoslemma we have
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
ℎ+ 120579
2
1le 119862nabla120579 (0)
2+ 119862int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
10038171003817100381710038171205791199051003817100381710038171003817 119889119904
+ 119862ℎ2int
119905
0
1003817100381710038171003817119906119905
1003817100381710038171003817
2
1119889119904
(95)
6 Full Discretization
Let 120597119880119899= (119880
119899minus119880
119899minus1)119896 be the backward difference quotient
of 119880119899 assume that 119860ℎ
= 119875ℎ119860 is a discrete analogue of 119860
(similarly 119861ℎ
= 119875ℎ119861) where 119875
ℎ 119871
2(Ω) rarr 119878
lowast
ℎthe 119871
2
projection is defined by
(119875ℎV 119868lowast
ℎVℎ) = (V 119868lowast
ℎVℎ) V isin 119871
2(Ω) V
ℎisin 119878
ℎ (96)
In order to define fully discrete approximation of (11) wediscretize the time by taking 119905
119899= 119899119896 119896 gt 0 119899 = 1 2 and
use the numerical quadrature
int
119905119899minus12
0
119892 (119904) 119889119904 asymp
119899
sum
119896=1
120596119899119896119892 (119905
119896minus12) 119905
119899minus12= (119899 minus
1
2) 119896
(97)
Here 120596119899119896 are the integrationweights andwe assume that
the following error estimate is valid
119902119899(119892) = int
119905119899minus12
0
119892 (119904) 119889119904minus
119899
sum
119896=1
120596119899119896119892 (119905
119896minus12)
le 1198621198962int
119905119899
0
(10038161003816100381610038161003816119892101584010038161003816100381610038161003816+100381610038161003816100381610038161198921015840101584010038161003816100381610038161003816) 119889119904
(98)
Now define our complete discrete FVE approximation of(11) by the following find 119880
119899isin 119878
ℎfor 119899 = 1 2 such that
for all Vℎisin 119878
ℎ
(120597119880119899 119868
lowast
ℎVℎ) + 119860 (119905
119899minus12 119880
119899minus12 119868
lowast
ℎVℎ)
+
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12 119880
119896minus12 119868
lowast
ℎVℎ)
= (119891119899minus12
119868lowast
ℎVℎ)
1198800 in 119878
ℎ
(99)
where 119880119899minus12= (119880
119899+ 119880
119899minus1)2
Theorem 19 Let 119906(119905) and 119880119899 be the solutions of problem (2)
and its complete discrete scheme (99) respectively Then forany 119879 gt 0 there exists a positive constant 119862 = 119862(119879) gt 0independent of ℎ such that for 0 lt 119905
119899le 119879
1003817100381710038171003817119906 (119905119899) minus 1198801198991003817100381710038171003817
le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905119899
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
+ 1198621198962(int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905119905
1003817100381710038171003817) 119889119904)
(100)
Proof Let us split the error into two parts 119906(119905119899) minus 119880
119899= 120588
119899+
120579119899 where 120588
119899= 119906(119905
119899)minus119881
ℎ119906(119905
119899) and 120579119899 = 119881
ℎ119906(119905
119899)minus119880
119899 and let119882 = 119881
ℎ119906(119905) isin 119878
ℎbe the Ritz-Volterra projection of 119906 Then
from (2) and (99) we have for all Vℎisin 119878
ℎthe following
(120597120579119899 119868
lowast
ℎVℎ) + 119860 (119905
119899minus12 120579
119899minus12 119868
lowast
ℎVℎ)
+
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12 120579
119896minus12 119868
lowast
ℎVℎ)
= minus (119903119899 119868
lowast
ℎVℎ) forallV
ℎisin 119878
ℎ
(101)
where
119903119899= 119903
1
119899+ 119903
2
119899+ 119903
3
119899+ 119903
4
119899
1199031
119899= 120597120588
119899
1199032
119899= 120597119906 (119905
119899) minus 119906
119905(119905
119899minus12)
1199033
119899= 119860(119905
119899minus12(119906 (119905
119899) + 119906 (119905
119899minus1))
2minus 119906 (119905
119899minus12))
1199034
119899= 119902
119899(119861
ℎ119882)
=
119899
sum
119896=1
120596119899119896119861ℎ(119905
119899minus12 119905
119896minus12119882
119896minus12 119868
lowast
ℎVℎ)
minus int
119905119899minus12
0
119861 (119905119899 119904119882 (119904) 119868
lowast
ℎVℎ) 119889119904
(102)
In fact by Taylor expansion
119906119899+1
= 119906119899+ 119896119906
1015840(119905
119899) + int
119905119899+1
119905119899
11990610158401015840(119904) (119905
119899+1minus 119904) 119889119904
= 119906119899+ 119896119906
1015840(119905
119899) +
1198962
211990610158401015840(119905
119899) +
1198963
6119906(3)
(119905119899)
+1
6int
119905119899+1
119905119899
119906(4)
(119904) (119905119899+1
minus 119904)3
119889119904
(103)
12 Journal of Mathematics
we have100381710038171003817100381710038171199031
119899
10038171003817100381710038171003817=
10038171003817100381710038171003817120597120588
11989910038171003817100381710038171003817le
1
119896int
119905119899
119905119899minus1
10038171003817100381710038171205881199051003817100381710038171003817 119889119904 le 119862
ℎ2
119896int
119905119899
119905119899minus1
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
100381710038171003817100381710038171199032
119899
10038171003817100381710038171003817=
10038171003817100381710038171003817120597119906 (119905
119899) minus 119906
119905(119905
119899minus12)10038171003817100381710038171003817
=1
119896
100381710038171003817100381710038171003817100381710038171003817
int
119905119899
119905119899minus1
(119906119905(119904) minus 119906
119905(119905
119899minus12)) 119889119904
100381710038171003817100381710038171003817100381710038171003817
le 119862119896int
119905119899
119905119899minus1
10038171003817100381710038171003817119906(3)
(119904)10038171003817100381710038171003817119889119904
100381710038171003817100381710038171199033
119899
10038171003817100381710038171003817=
100381710038171003817100381710038171003817100381710038171003817
119860(119905119899minus12
119906 (119905
119899) + 119906 (119905
119899minus1)
2minus 119906 (119905
119899minus12) 119868
lowast
ℎVℎ)
100381710038171003817100381710038171003817100381710038171003817
le 119862119896int
119905119899
119905119899minus1
1003817100381710038171003817119860119906119905119905(119904)
1003817100381710038171003817 119889119904 le 119862119896int
119905119899
119905119899minus1
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
(104)
In addition the quadrature error satisfies100381710038171003817100381710038171199034
119899
10038171003817100381710038171003817= 119902
119899minus12(119861
ℎ119882)
=
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12119882
119896minus12 119868
lowast
ℎVℎ)
minus int
119905119899minus12
0
119861 (119905119899 119904119882 (119904) 119868
lowast
ℎVℎ) 119889119904
le 1198621198962int
119905119899
0
1003817100381710038171003817(119861ℎ119882)
119904119904
1003817100381710038171003817 119889119904
le 1198621198962int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172) 119889119904
119896
119873
sum
119899=1
10038171003817100381710038171199031198991003817100381710038171003817 le 119862ℎ
2int
119905119899
0
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
+ 1198621198962int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172+10038171003817100381710038171003817119906(3)10038171003817100381710038171003817
) 119889119904
(105)
Taking Vℎ= 120579
119899minus12 in (101) and noting that (120597120579119899 119868lowastℎ120579119899minus12
) =
(12)120597|||120579119899|||
2 there is1003816100381610038161003816
1003816100381610038161003816
10038161003816100381610038161205791198991003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816
2
minus10038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus110038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
+ 211989611988810038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus1210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
1
le 1198621198962
119899
sum
119896=1
10038171003817100381710038171003817120579119896minus12100381710038171003817100381710038171
10038171003817100381710038171003817120579119899minus12100381710038171003817100381710038171
+ 1198621198961003817100381710038171003817119903119899
1003817100381710038171003817
10038171003817100381710038171003817120579119899minus1210038171003817100381710038171003817
le11989611988810038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus1210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
1+ 119862119896
2
119899
sum
119896=1
10038171003817100381710038171003817120579119896minus1210038171003817100381710038171003817
2
1+ 119862119896
10038171003817100381710038171199031198991003817100381710038171003817
10038171003817100381710038171003817120579119899minus1210038171003817100381710038171003817
(106)
Summing from 119899 = 1 to 119873 and then after cancelling thecommon factor and using Gronwallrsquos lemma we obtain
10038161003816100381610038161003816
10038161003816100381610038161003816
1003816100381610038161003816100381612057911987310038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
le 11986210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579010038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
+ 119862119896
119873
sum
119896=1
10038171003817100381710038171199031198991003817100381710038171003817 (
1003817100381710038171003817100381712057911989610038171003817100381710038171003817
+10038171003817100381710038171003817120579119896minus1210038171003817100381710038171003817
) (107)
and then
10038161003816100381610038161003816
10038161003816100381610038161003816
1003816100381610038161003816100381612057911987310038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816le 119862
10038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579010038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816+ 119862119896
119873
sum
119899=1
10038171003817100381710038171199031198991003817100381710038171003817
(108)
the theorem follows from the estimates of 120588119899 and 119903119899
References
[1] Z Q Cai ldquoOn the finite volume element methodrdquo NumerischeMathematik vol 58 no 7 pp 713ndash735 1991
[2] S H Chou and D Y Kwak ldquoAnalysis and convergence of aMAC-like scheme for the generalized Stokes problemrdquo Numer-ical Methods for Partial Differential Equations vol 13 no 2 pp147ndash162 1997
[3] P Chatzipantelidis ldquoA finite volume method based on theCrouzeix-Raviart element for elliptic PDErsquos in two dimensionsrdquoNumerische Mathematik vol 82 no 3 pp 409ndash432 1999
[4] P Chatzipantelidis ldquoFinite volumemethods for elliptic PDErsquos anew approachrdquo Mathematical Modelling and Numerical Analy-sis vol 36 no 2 pp 307ndash324 2002
[5] P Chatzipantelidis R D Lazarov and V Thomee ldquoErrorestimates for a finite volume element method for parabolicequations in convex polygonal domainsrdquoNumericalMethods forPartial Differential Equations vol 20 no 5 pp 650ndash674 2004
[6] R E Ewing R D Lazarov and Y Lin ldquoFinite volume elementapproximations of nonlocal in time one-dimensional flows inporous mediardquo Computing vol 64 no 2 pp 157ndash182 2000
[7] R Ewing R Lazarov and Y Lin ldquoFinite volume elementapproximations of nonlocal reactive flows in porous mediardquoNumericalMethods for Partial Differential Equations vol 16 no3 pp 285ndash311 2000
[8] R E Ewing T Lin andY Lin ldquoOn the accuracy of the finite vol-ume element method based on piecewise linear polynomialsrdquoSIAM Journal on Numerical Analysis vol 39 no 6 pp 1865ndash1888 2002
[9] R K Sinha and J Geiser ldquoError estimates for finite volumeelement methods for convection-diffusion-reaction equationsrdquoApplied Numerical Mathematics vol 57 no 1 pp 59ndash72 2007
[10] S H Chou ldquoAnalysis and convergence of a covolume methodfor the generalized Stokes problemrdquo Mathematics of Computa-tion vol 66 no 217 pp 85ndash104 1997
[11] M Berggren ldquoA vertex-centered dual discontinuous Galerkinmethodrdquo Journal of Computational and Applied Mathematicsvol 192 no 1 pp 175ndash181 2006
[12] S H Chou and D Y Kwak ldquoMultigrid algorithms for a vertex-centered covolume method for elliptic problemsrdquo NumerischeMathematik vol 90 no 3 pp 441ndash458 2002
[13] R Eymard T Gallouet and R Herbin Finite Volume MethodsHandbook of Numerical Analysis North-Holland AmsterdamThe Netherlands 2000
[14] V R Voller Basic Control Volume Finite Element Methods forFluids and Solids World Scientific Publishing 2009
[15] J Huang and S Xi ldquoOn the finite volume element method forgeneral self-adjoint elliptic problemsrdquo SIAM Journal on Numer-ical Analysis vol 35 no 5 pp 1762ndash1774 1998
[16] X Ma S Shu and A Zhou ldquoSymmetric finite volume discreti-zations for parabolic problemsrdquo Computer Methods in AppliedMechanics and Engineering vol 192 no 39-40 pp 4467ndash44852003
[17] R D Lazarov and S Z Tomov ldquoAdaptive finite volume elementmethod for convection-diffusion-reaction problems in 3-Drdquo inScientific Computing and Applications vol 7 of Advances inComputation Theory and Practice pp 91ndash106 Nova SciencePublishers Huntington NY USA 2001
[18] I DMishevFinite volume and finite volume elementmethods fornon-symmetric problems [PhD thesis] Texas AampM University1997 Technical Report ISC-96-04-MATH
Journal of Mathematics 13
[19] C Chen and T Shih Finite Element Methods for Integrodifferen-tial Equations World Scientific Publishing Singapore 1998
[20] Y P Lin V Thomee and L B Wahlbin ldquoRitz-Volterra pro-jections to finite-element spaces and applications to integrod-ifferential and related equationsrdquo SIAM Journal on NumericalAnalysis vol 28 no 4 pp 1047ndash1070 1991
[21] VThomeeGalerkin Finite Element Methods for Parabolic Prob-lems Springer Series in Computational Mathematics SpringerNew York NY USA 2006
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical Problems in Engineering
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Differential EquationsInternational Journal of
Volume 2014
Applied MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Journal of
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Mathematical PhysicsAdvances in
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OptimizationJournal of
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CombinatoricsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
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Operations ResearchAdvances in
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Function Spaces
Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of Mathematics and Mathematical Sciences
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Algebra
Discrete Dynamics in Nature and Society
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Decision SciencesAdvances in
Discrete MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
Volume 2014 Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Stochastic AnalysisInternational Journal of
Journal of Mathematics 11
Proof Setting Vℎ= 120579
119905in (87) we obtain
10038171003817100381710038171205791199051003817100381710038171003817
2
ℎ+1
2
119889
119889119905119860 (119905 120579 119868
lowast
ℎ120579)
=1
2119860
119905(119905 120579 119868
lowast
ℎ120579) +
1
2[119860 (119905 120579
119905 119868
lowast
ℎ120579) minus 119860 (119905 120579 119868
lowast
ℎ120579119905)]
119861 (119905 119905 120579 (119905) 119868lowast
ℎ120579 (119905)) + int
119905
0
119861119905(119905 119904 120579 (119904) 119868
lowast
ℎ120579 (119905)) 119889119904
minus119889
119889119905int
119905
0
119861 (119905 119904 120579 (119904) 119868lowast
ℎ120579 (119905)) 119889119904 minus (120588
119905 119868
lowast
ℎ120579119905)
minus 120576ℎ((119881
ℎ119906)
119905 120579
119905) + ((119881
ℎ119906)
119905 120579) minus ((119881
ℎ119906)
119905 119868
lowast
ℎ120579)
(94)
It follows thus that using integration in 119905 and Gronwallrsquoslemma we have
int
119905
0
10038171003817100381710038171205791199051003817100381710038171003817
2
ℎ+ 120579
2
1le 119862nabla120579 (0)
2+ 119862int
119905
0
10038171003817100381710038171205881199051003817100381710038171003817
10038171003817100381710038171205791199051003817100381710038171003817 119889119904
+ 119862ℎ2int
119905
0
1003817100381710038171003817119906119905
1003817100381710038171003817
2
1119889119904
(95)
6 Full Discretization
Let 120597119880119899= (119880
119899minus119880
119899minus1)119896 be the backward difference quotient
of 119880119899 assume that 119860ℎ
= 119875ℎ119860 is a discrete analogue of 119860
(similarly 119861ℎ
= 119875ℎ119861) where 119875
ℎ 119871
2(Ω) rarr 119878
lowast
ℎthe 119871
2
projection is defined by
(119875ℎV 119868lowast
ℎVℎ) = (V 119868lowast
ℎVℎ) V isin 119871
2(Ω) V
ℎisin 119878
ℎ (96)
In order to define fully discrete approximation of (11) wediscretize the time by taking 119905
119899= 119899119896 119896 gt 0 119899 = 1 2 and
use the numerical quadrature
int
119905119899minus12
0
119892 (119904) 119889119904 asymp
119899
sum
119896=1
120596119899119896119892 (119905
119896minus12) 119905
119899minus12= (119899 minus
1
2) 119896
(97)
Here 120596119899119896 are the integrationweights andwe assume that
the following error estimate is valid
119902119899(119892) = int
119905119899minus12
0
119892 (119904) 119889119904minus
119899
sum
119896=1
120596119899119896119892 (119905
119896minus12)
le 1198621198962int
119905119899
0
(10038161003816100381610038161003816119892101584010038161003816100381610038161003816+100381610038161003816100381610038161198921015840101584010038161003816100381610038161003816) 119889119904
(98)
Now define our complete discrete FVE approximation of(11) by the following find 119880
119899isin 119878
ℎfor 119899 = 1 2 such that
for all Vℎisin 119878
ℎ
(120597119880119899 119868
lowast
ℎVℎ) + 119860 (119905
119899minus12 119880
119899minus12 119868
lowast
ℎVℎ)
+
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12 119880
119896minus12 119868
lowast
ℎVℎ)
= (119891119899minus12
119868lowast
ℎVℎ)
1198800 in 119878
ℎ
(99)
where 119880119899minus12= (119880
119899+ 119880
119899minus1)2
Theorem 19 Let 119906(119905) and 119880119899 be the solutions of problem (2)
and its complete discrete scheme (99) respectively Then forany 119879 gt 0 there exists a positive constant 119862 = 119862(119879) gt 0independent of ℎ such that for 0 lt 119905
119899le 119879
1003817100381710038171003817119906 (119905119899) minus 1198801198991003817100381710038171003817
le 119862ℎ2(10038171003817100381710038171199060
10038171003817100381710038172+ int
119905119899
0
1003817100381710038171003817119906119905
10038171003817100381710038172119889119904)
+ 1198621198962(int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905119905
1003817100381710038171003817) 119889119904)
(100)
Proof Let us split the error into two parts 119906(119905119899) minus 119880
119899= 120588
119899+
120579119899 where 120588
119899= 119906(119905
119899)minus119881
ℎ119906(119905
119899) and 120579119899 = 119881
ℎ119906(119905
119899)minus119880
119899 and let119882 = 119881
ℎ119906(119905) isin 119878
ℎbe the Ritz-Volterra projection of 119906 Then
from (2) and (99) we have for all Vℎisin 119878
ℎthe following
(120597120579119899 119868
lowast
ℎVℎ) + 119860 (119905
119899minus12 120579
119899minus12 119868
lowast
ℎVℎ)
+
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12 120579
119896minus12 119868
lowast
ℎVℎ)
= minus (119903119899 119868
lowast
ℎVℎ) forallV
ℎisin 119878
ℎ
(101)
where
119903119899= 119903
1
119899+ 119903
2
119899+ 119903
3
119899+ 119903
4
119899
1199031
119899= 120597120588
119899
1199032
119899= 120597119906 (119905
119899) minus 119906
119905(119905
119899minus12)
1199033
119899= 119860(119905
119899minus12(119906 (119905
119899) + 119906 (119905
119899minus1))
2minus 119906 (119905
119899minus12))
1199034
119899= 119902
119899(119861
ℎ119882)
=
119899
sum
119896=1
120596119899119896119861ℎ(119905
119899minus12 119905
119896minus12119882
119896minus12 119868
lowast
ℎVℎ)
minus int
119905119899minus12
0
119861 (119905119899 119904119882 (119904) 119868
lowast
ℎVℎ) 119889119904
(102)
In fact by Taylor expansion
119906119899+1
= 119906119899+ 119896119906
1015840(119905
119899) + int
119905119899+1
119905119899
11990610158401015840(119904) (119905
119899+1minus 119904) 119889119904
= 119906119899+ 119896119906
1015840(119905
119899) +
1198962
211990610158401015840(119905
119899) +
1198963
6119906(3)
(119905119899)
+1
6int
119905119899+1
119905119899
119906(4)
(119904) (119905119899+1
minus 119904)3
119889119904
(103)
12 Journal of Mathematics
we have100381710038171003817100381710038171199031
119899
10038171003817100381710038171003817=
10038171003817100381710038171003817120597120588
11989910038171003817100381710038171003817le
1
119896int
119905119899
119905119899minus1
10038171003817100381710038171205881199051003817100381710038171003817 119889119904 le 119862
ℎ2
119896int
119905119899
119905119899minus1
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
100381710038171003817100381710038171199032
119899
10038171003817100381710038171003817=
10038171003817100381710038171003817120597119906 (119905
119899) minus 119906
119905(119905
119899minus12)10038171003817100381710038171003817
=1
119896
100381710038171003817100381710038171003817100381710038171003817
int
119905119899
119905119899minus1
(119906119905(119904) minus 119906
119905(119905
119899minus12)) 119889119904
100381710038171003817100381710038171003817100381710038171003817
le 119862119896int
119905119899
119905119899minus1
10038171003817100381710038171003817119906(3)
(119904)10038171003817100381710038171003817119889119904
100381710038171003817100381710038171199033
119899
10038171003817100381710038171003817=
100381710038171003817100381710038171003817100381710038171003817
119860(119905119899minus12
119906 (119905
119899) + 119906 (119905
119899minus1)
2minus 119906 (119905
119899minus12) 119868
lowast
ℎVℎ)
100381710038171003817100381710038171003817100381710038171003817
le 119862119896int
119905119899
119905119899minus1
1003817100381710038171003817119860119906119905119905(119904)
1003817100381710038171003817 119889119904 le 119862119896int
119905119899
119905119899minus1
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
(104)
In addition the quadrature error satisfies100381710038171003817100381710038171199034
119899
10038171003817100381710038171003817= 119902
119899minus12(119861
ℎ119882)
=
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12119882
119896minus12 119868
lowast
ℎVℎ)
minus int
119905119899minus12
0
119861 (119905119899 119904119882 (119904) 119868
lowast
ℎVℎ) 119889119904
le 1198621198962int
119905119899
0
1003817100381710038171003817(119861ℎ119882)
119904119904
1003817100381710038171003817 119889119904
le 1198621198962int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172) 119889119904
119896
119873
sum
119899=1
10038171003817100381710038171199031198991003817100381710038171003817 le 119862ℎ
2int
119905119899
0
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
+ 1198621198962int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172+10038171003817100381710038171003817119906(3)10038171003817100381710038171003817
) 119889119904
(105)
Taking Vℎ= 120579
119899minus12 in (101) and noting that (120597120579119899 119868lowastℎ120579119899minus12
) =
(12)120597|||120579119899|||
2 there is1003816100381610038161003816
1003816100381610038161003816
10038161003816100381610038161205791198991003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816
2
minus10038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus110038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
+ 211989611988810038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus1210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
1
le 1198621198962
119899
sum
119896=1
10038171003817100381710038171003817120579119896minus12100381710038171003817100381710038171
10038171003817100381710038171003817120579119899minus12100381710038171003817100381710038171
+ 1198621198961003817100381710038171003817119903119899
1003817100381710038171003817
10038171003817100381710038171003817120579119899minus1210038171003817100381710038171003817
le11989611988810038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus1210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
1+ 119862119896
2
119899
sum
119896=1
10038171003817100381710038171003817120579119896minus1210038171003817100381710038171003817
2
1+ 119862119896
10038171003817100381710038171199031198991003817100381710038171003817
10038171003817100381710038171003817120579119899minus1210038171003817100381710038171003817
(106)
Summing from 119899 = 1 to 119873 and then after cancelling thecommon factor and using Gronwallrsquos lemma we obtain
10038161003816100381610038161003816
10038161003816100381610038161003816
1003816100381610038161003816100381612057911987310038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
le 11986210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579010038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
+ 119862119896
119873
sum
119896=1
10038171003817100381710038171199031198991003817100381710038171003817 (
1003817100381710038171003817100381712057911989610038171003817100381710038171003817
+10038171003817100381710038171003817120579119896minus1210038171003817100381710038171003817
) (107)
and then
10038161003816100381610038161003816
10038161003816100381610038161003816
1003816100381610038161003816100381612057911987310038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816le 119862
10038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579010038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816+ 119862119896
119873
sum
119899=1
10038171003817100381710038171199031198991003817100381710038171003817
(108)
the theorem follows from the estimates of 120588119899 and 119903119899
References
[1] Z Q Cai ldquoOn the finite volume element methodrdquo NumerischeMathematik vol 58 no 7 pp 713ndash735 1991
[2] S H Chou and D Y Kwak ldquoAnalysis and convergence of aMAC-like scheme for the generalized Stokes problemrdquo Numer-ical Methods for Partial Differential Equations vol 13 no 2 pp147ndash162 1997
[3] P Chatzipantelidis ldquoA finite volume method based on theCrouzeix-Raviart element for elliptic PDErsquos in two dimensionsrdquoNumerische Mathematik vol 82 no 3 pp 409ndash432 1999
[4] P Chatzipantelidis ldquoFinite volumemethods for elliptic PDErsquos anew approachrdquo Mathematical Modelling and Numerical Analy-sis vol 36 no 2 pp 307ndash324 2002
[5] P Chatzipantelidis R D Lazarov and V Thomee ldquoErrorestimates for a finite volume element method for parabolicequations in convex polygonal domainsrdquoNumericalMethods forPartial Differential Equations vol 20 no 5 pp 650ndash674 2004
[6] R E Ewing R D Lazarov and Y Lin ldquoFinite volume elementapproximations of nonlocal in time one-dimensional flows inporous mediardquo Computing vol 64 no 2 pp 157ndash182 2000
[7] R Ewing R Lazarov and Y Lin ldquoFinite volume elementapproximations of nonlocal reactive flows in porous mediardquoNumericalMethods for Partial Differential Equations vol 16 no3 pp 285ndash311 2000
[8] R E Ewing T Lin andY Lin ldquoOn the accuracy of the finite vol-ume element method based on piecewise linear polynomialsrdquoSIAM Journal on Numerical Analysis vol 39 no 6 pp 1865ndash1888 2002
[9] R K Sinha and J Geiser ldquoError estimates for finite volumeelement methods for convection-diffusion-reaction equationsrdquoApplied Numerical Mathematics vol 57 no 1 pp 59ndash72 2007
[10] S H Chou ldquoAnalysis and convergence of a covolume methodfor the generalized Stokes problemrdquo Mathematics of Computa-tion vol 66 no 217 pp 85ndash104 1997
[11] M Berggren ldquoA vertex-centered dual discontinuous Galerkinmethodrdquo Journal of Computational and Applied Mathematicsvol 192 no 1 pp 175ndash181 2006
[12] S H Chou and D Y Kwak ldquoMultigrid algorithms for a vertex-centered covolume method for elliptic problemsrdquo NumerischeMathematik vol 90 no 3 pp 441ndash458 2002
[13] R Eymard T Gallouet and R Herbin Finite Volume MethodsHandbook of Numerical Analysis North-Holland AmsterdamThe Netherlands 2000
[14] V R Voller Basic Control Volume Finite Element Methods forFluids and Solids World Scientific Publishing 2009
[15] J Huang and S Xi ldquoOn the finite volume element method forgeneral self-adjoint elliptic problemsrdquo SIAM Journal on Numer-ical Analysis vol 35 no 5 pp 1762ndash1774 1998
[16] X Ma S Shu and A Zhou ldquoSymmetric finite volume discreti-zations for parabolic problemsrdquo Computer Methods in AppliedMechanics and Engineering vol 192 no 39-40 pp 4467ndash44852003
[17] R D Lazarov and S Z Tomov ldquoAdaptive finite volume elementmethod for convection-diffusion-reaction problems in 3-Drdquo inScientific Computing and Applications vol 7 of Advances inComputation Theory and Practice pp 91ndash106 Nova SciencePublishers Huntington NY USA 2001
[18] I DMishevFinite volume and finite volume elementmethods fornon-symmetric problems [PhD thesis] Texas AampM University1997 Technical Report ISC-96-04-MATH
Journal of Mathematics 13
[19] C Chen and T Shih Finite Element Methods for Integrodifferen-tial Equations World Scientific Publishing Singapore 1998
[20] Y P Lin V Thomee and L B Wahlbin ldquoRitz-Volterra pro-jections to finite-element spaces and applications to integrod-ifferential and related equationsrdquo SIAM Journal on NumericalAnalysis vol 28 no 4 pp 1047ndash1070 1991
[21] VThomeeGalerkin Finite Element Methods for Parabolic Prob-lems Springer Series in Computational Mathematics SpringerNew York NY USA 2006
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical Problems in Engineering
Hindawi Publishing Corporationhttpwwwhindawicom
Differential EquationsInternational Journal of
Volume 2014
Applied MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Probability and StatisticsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
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Mathematical PhysicsAdvances in
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OptimizationJournal of
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CombinatoricsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
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Function Spaces
Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of Mathematics and Mathematical Sciences
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The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Algebra
Discrete Dynamics in Nature and Society
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
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Decision SciencesAdvances in
Discrete MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
Volume 2014 Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Stochastic AnalysisInternational Journal of
12 Journal of Mathematics
we have100381710038171003817100381710038171199031
119899
10038171003817100381710038171003817=
10038171003817100381710038171003817120597120588
11989910038171003817100381710038171003817le
1
119896int
119905119899
119905119899minus1
10038171003817100381710038171205881199051003817100381710038171003817 119889119904 le 119862
ℎ2
119896int
119905119899
119905119899minus1
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
100381710038171003817100381710038171199032
119899
10038171003817100381710038171003817=
10038171003817100381710038171003817120597119906 (119905
119899) minus 119906
119905(119905
119899minus12)10038171003817100381710038171003817
=1
119896
100381710038171003817100381710038171003817100381710038171003817
int
119905119899
119905119899minus1
(119906119905(119904) minus 119906
119905(119905
119899minus12)) 119889119904
100381710038171003817100381710038171003817100381710038171003817
le 119862119896int
119905119899
119905119899minus1
10038171003817100381710038171003817119906(3)
(119904)10038171003817100381710038171003817119889119904
100381710038171003817100381710038171199033
119899
10038171003817100381710038171003817=
100381710038171003817100381710038171003817100381710038171003817
119860(119905119899minus12
119906 (119905
119899) + 119906 (119905
119899minus1)
2minus 119906 (119905
119899minus12) 119868
lowast
ℎVℎ)
100381710038171003817100381710038171003817100381710038171003817
le 119862119896int
119905119899
119905119899minus1
1003817100381710038171003817119860119906119905119905(119904)
1003817100381710038171003817 119889119904 le 119862119896int
119905119899
119905119899minus1
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
(104)
In addition the quadrature error satisfies100381710038171003817100381710038171199034
119899
10038171003817100381710038171003817= 119902
119899minus12(119861
ℎ119882)
=
119899
sum
119896=1
120596119899119896119861 (119905
119899minus12 119905
119896minus12119882
119896minus12 119868
lowast
ℎVℎ)
minus int
119905119899minus12
0
119861 (119905119899 119904119882 (119904) 119868
lowast
ℎVℎ) 119889119904
le 1198621198962int
119905119899
0
1003817100381710038171003817(119861ℎ119882)
119904119904
1003817100381710038171003817 119889119904
le 1198621198962int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172) 119889119904
119896
119873
sum
119899=1
10038171003817100381710038171199031198991003817100381710038171003817 le 119862ℎ
2int
119905119899
0
1003817100381710038171003817119906119905119905
10038171003817100381710038172119889119904
+ 1198621198962int
119905119899
0
(1199062 +1003817100381710038171003817119906119905
10038171003817100381710038172+1003817100381710038171003817119906119905119905
10038171003817100381710038172+10038171003817100381710038171003817119906(3)10038171003817100381710038171003817
) 119889119904
(105)
Taking Vℎ= 120579
119899minus12 in (101) and noting that (120597120579119899 119868lowastℎ120579119899minus12
) =
(12)120597|||120579119899|||
2 there is1003816100381610038161003816
1003816100381610038161003816
10038161003816100381610038161205791198991003816100381610038161003816
1003816100381610038161003816
1003816100381610038161003816
2
minus10038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus110038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
+ 211989611988810038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus1210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
1
le 1198621198962
119899
sum
119896=1
10038171003817100381710038171003817120579119896minus12100381710038171003817100381710038171
10038171003817100381710038171003817120579119899minus12100381710038171003817100381710038171
+ 1198621198961003817100381710038171003817119903119899
1003817100381710038171003817
10038171003817100381710038171003817120579119899minus1210038171003817100381710038171003817
le11989611988810038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579119899minus1210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
1+ 119862119896
2
119899
sum
119896=1
10038171003817100381710038171003817120579119896minus1210038171003817100381710038171003817
2
1+ 119862119896
10038171003817100381710038171199031198991003817100381710038171003817
10038171003817100381710038171003817120579119899minus1210038171003817100381710038171003817
(106)
Summing from 119899 = 1 to 119873 and then after cancelling thecommon factor and using Gronwallrsquos lemma we obtain
10038161003816100381610038161003816
10038161003816100381610038161003816
1003816100381610038161003816100381612057911987310038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
le 11986210038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579010038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816
2
+ 119862119896
119873
sum
119896=1
10038171003817100381710038171199031198991003817100381710038171003817 (
1003817100381710038171003817100381712057911989610038171003817100381710038171003817
+10038171003817100381710038171003817120579119896minus1210038171003817100381710038171003817
) (107)
and then
10038161003816100381610038161003816
10038161003816100381610038161003816
1003816100381610038161003816100381612057911987310038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816le 119862
10038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816120579010038161003816100381610038161003816
10038161003816100381610038161003816
10038161003816100381610038161003816+ 119862119896
119873
sum
119899=1
10038171003817100381710038171199031198991003817100381710038171003817
(108)
the theorem follows from the estimates of 120588119899 and 119903119899
References
[1] Z Q Cai ldquoOn the finite volume element methodrdquo NumerischeMathematik vol 58 no 7 pp 713ndash735 1991
[2] S H Chou and D Y Kwak ldquoAnalysis and convergence of aMAC-like scheme for the generalized Stokes problemrdquo Numer-ical Methods for Partial Differential Equations vol 13 no 2 pp147ndash162 1997
[3] P Chatzipantelidis ldquoA finite volume method based on theCrouzeix-Raviart element for elliptic PDErsquos in two dimensionsrdquoNumerische Mathematik vol 82 no 3 pp 409ndash432 1999
[4] P Chatzipantelidis ldquoFinite volumemethods for elliptic PDErsquos anew approachrdquo Mathematical Modelling and Numerical Analy-sis vol 36 no 2 pp 307ndash324 2002
[5] P Chatzipantelidis R D Lazarov and V Thomee ldquoErrorestimates for a finite volume element method for parabolicequations in convex polygonal domainsrdquoNumericalMethods forPartial Differential Equations vol 20 no 5 pp 650ndash674 2004
[6] R E Ewing R D Lazarov and Y Lin ldquoFinite volume elementapproximations of nonlocal in time one-dimensional flows inporous mediardquo Computing vol 64 no 2 pp 157ndash182 2000
[7] R Ewing R Lazarov and Y Lin ldquoFinite volume elementapproximations of nonlocal reactive flows in porous mediardquoNumericalMethods for Partial Differential Equations vol 16 no3 pp 285ndash311 2000
[8] R E Ewing T Lin andY Lin ldquoOn the accuracy of the finite vol-ume element method based on piecewise linear polynomialsrdquoSIAM Journal on Numerical Analysis vol 39 no 6 pp 1865ndash1888 2002
[9] R K Sinha and J Geiser ldquoError estimates for finite volumeelement methods for convection-diffusion-reaction equationsrdquoApplied Numerical Mathematics vol 57 no 1 pp 59ndash72 2007
[10] S H Chou ldquoAnalysis and convergence of a covolume methodfor the generalized Stokes problemrdquo Mathematics of Computa-tion vol 66 no 217 pp 85ndash104 1997
[11] M Berggren ldquoA vertex-centered dual discontinuous Galerkinmethodrdquo Journal of Computational and Applied Mathematicsvol 192 no 1 pp 175ndash181 2006
[12] S H Chou and D Y Kwak ldquoMultigrid algorithms for a vertex-centered covolume method for elliptic problemsrdquo NumerischeMathematik vol 90 no 3 pp 441ndash458 2002
[13] R Eymard T Gallouet and R Herbin Finite Volume MethodsHandbook of Numerical Analysis North-Holland AmsterdamThe Netherlands 2000
[14] V R Voller Basic Control Volume Finite Element Methods forFluids and Solids World Scientific Publishing 2009
[15] J Huang and S Xi ldquoOn the finite volume element method forgeneral self-adjoint elliptic problemsrdquo SIAM Journal on Numer-ical Analysis vol 35 no 5 pp 1762ndash1774 1998
[16] X Ma S Shu and A Zhou ldquoSymmetric finite volume discreti-zations for parabolic problemsrdquo Computer Methods in AppliedMechanics and Engineering vol 192 no 39-40 pp 4467ndash44852003
[17] R D Lazarov and S Z Tomov ldquoAdaptive finite volume elementmethod for convection-diffusion-reaction problems in 3-Drdquo inScientific Computing and Applications vol 7 of Advances inComputation Theory and Practice pp 91ndash106 Nova SciencePublishers Huntington NY USA 2001
[18] I DMishevFinite volume and finite volume elementmethods fornon-symmetric problems [PhD thesis] Texas AampM University1997 Technical Report ISC-96-04-MATH
Journal of Mathematics 13
[19] C Chen and T Shih Finite Element Methods for Integrodifferen-tial Equations World Scientific Publishing Singapore 1998
[20] Y P Lin V Thomee and L B Wahlbin ldquoRitz-Volterra pro-jections to finite-element spaces and applications to integrod-ifferential and related equationsrdquo SIAM Journal on NumericalAnalysis vol 28 no 4 pp 1047ndash1070 1991
[21] VThomeeGalerkin Finite Element Methods for Parabolic Prob-lems Springer Series in Computational Mathematics SpringerNew York NY USA 2006
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical Problems in Engineering
Hindawi Publishing Corporationhttpwwwhindawicom
Differential EquationsInternational Journal of
Volume 2014
Applied MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Probability and StatisticsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical PhysicsAdvances in
Complex AnalysisJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
OptimizationJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CombinatoricsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Operations ResearchAdvances in
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Function Spaces
Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of Mathematics and Mathematical Sciences
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Algebra
Discrete Dynamics in Nature and Society
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Decision SciencesAdvances in
Discrete MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
Volume 2014 Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Stochastic AnalysisInternational Journal of
Journal of Mathematics 13
[19] C Chen and T Shih Finite Element Methods for Integrodifferen-tial Equations World Scientific Publishing Singapore 1998
[20] Y P Lin V Thomee and L B Wahlbin ldquoRitz-Volterra pro-jections to finite-element spaces and applications to integrod-ifferential and related equationsrdquo SIAM Journal on NumericalAnalysis vol 28 no 4 pp 1047ndash1070 1991
[21] VThomeeGalerkin Finite Element Methods for Parabolic Prob-lems Springer Series in Computational Mathematics SpringerNew York NY USA 2006
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical Problems in Engineering
Hindawi Publishing Corporationhttpwwwhindawicom
Differential EquationsInternational Journal of
Volume 2014
Applied MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Probability and StatisticsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical PhysicsAdvances in
Complex AnalysisJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
OptimizationJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CombinatoricsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Operations ResearchAdvances in
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Function Spaces
Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of Mathematics and Mathematical Sciences
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Algebra
Discrete Dynamics in Nature and Society
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Decision SciencesAdvances in
Discrete MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
Volume 2014 Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Stochastic AnalysisInternational Journal of
Submit your manuscripts athttpwwwhindawicom
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical Problems in Engineering
Hindawi Publishing Corporationhttpwwwhindawicom
Differential EquationsInternational Journal of
Volume 2014
Applied MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Probability and StatisticsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Mathematical PhysicsAdvances in
Complex AnalysisJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
OptimizationJournal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
CombinatoricsHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Operations ResearchAdvances in
Journal of
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Function Spaces
Abstract and Applied AnalysisHindawi Publishing Corporationhttpwwwhindawicom Volume 2014
International Journal of Mathematics and Mathematical Sciences
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Algebra
Discrete Dynamics in Nature and Society
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Decision SciencesAdvances in
Discrete MathematicsJournal of
Hindawi Publishing Corporationhttpwwwhindawicom
Volume 2014 Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014
Stochastic AnalysisInternational Journal of