Download - Clausnitzer Introduction to Feflow
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Volker Clausnitzer
Introduction to FEFLOW
DHI Groundwater Modelling Centre
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FEFLOW More than GroundwaterFEFLOW handles groundwater flow and related processes in one software environment, one user interface, and one simulation model:
Variably saturated flow Contaminant transport Heat transport Density-affected flow Chemical reactions And more ...
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FEFLOW More than GroundwaterPrimary development goal: FEFLOW is intented to be
Easy to use and intuitive to quickly master everyday groundwater projects,
but at the same time
Powerful and comprehensive to model complex subsurface processes.
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Complex Processes - Geometry Finite-element discretization Triangular or quad elements (2D) Prisms or cuboids (3D) 3D or 2D horizontal/vertical/axisymmetric projection 1D and 2D for fracture/pipe/borehole flow
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Complex Processes - PhysicsGroundwater and vadose-zone flow
Saturated flow (Darcy law) Unconfined conditions (different approaches) Unsaturated / variably saturated flow (Richards equation) Fracture flow Density- and viscosity-dependent flow
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Complex Processes - PhysicsTransport
Heat transport (advection-conduction equation) Solute transport (advection-diffusion equation) Combined solute/heat transport Sorption, Decay Multispecies simulation Kinetic reaction systems
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Ease of use
User interface for preprocessing, simulation, and postprocessing GIS/CAD/ASCII file interfaces for import and export 2D/3D map support Advanced computational methods
Powerful mesh generators Automatic time-stepping scheme Algebraic multigrid solver Parallelization
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Visualization
2D top / cross-section views 3D views
2D / 3D map support 3D clipping and carving Live, interactive visualization
during simulation run
Hardware acceleration via OpenGL
3D stereoscopic display/projector support currently in betatesting
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FEFLOW Viewer Free (no license required) Works with existing FEFLOW models Visualization and analysis Export of figures and animations Model and results files Use by modeler
No license necessary for postprocessing
Share your model with colleagues even if licenses are limited
Usage by consulting clients No need to purchase an additional license
Deliver viewable model files to customers
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Extensibility Open programming interface
Documented API interface User can develop plug-ins for
oAdditional functionalityoWorkflow automation
Application Examples Groundwater / surface water coupling Integration of technical installations in geothermal modeling Import of model properties Export of model results
Development Services Plug-in development as a consulting service
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Fields of Application Regional groundwater management
Mine water management
Construction and tunneling
Groundwater surface water interaction
Agriculture (irrigation, drainage, salinization, nutrient management)
Remediation / natural attenuation
Capture-zone delineation
Saltwater intrusion
Geothermal energy
Industrial porous materials
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FEFLOW Community
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FEFLOW Community
www.feflow.info/forum
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User Support We help by
Giving advice on FEFLOW modeling
Analyzing possible model improvements
Explaining theoretical background and functionality
In addition, we offer Training courses Solutions Software customization Consulting in modeling
projects Model review
FEFLOW ServicesTeam
Support Training Plug-in Solutions
Dipl.-Ing. Alexander Renz
Dipl.-Ing. Julia Mayer
Dipl.-Ing.Bastian Rau
Dipl.-Ing. Peter Schtzl
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Why FEFLOW? Highly scalable software package
Different feature levels available Optimal cost efficiency for every application Upgrades possible at any time
One software for current and future projects No need for additional software and training Saves time and money
Commercial software DHI guarantees consistent services Close contact to support staff Software performance benchmarked and documented Quality assurance Ongoing development
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Application Examples
1. Optimization of landscape water regime
2. Construction of an underground liquefied natural-gas storage system
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Agricultural Development PlanningGlietzener Polder, Germany
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ObjectivesConcept for landscape water regime that accommodates agricultural, environmental, and general landscape water balance goals:
Improvement of agricultural conditionsSustainment of low-water discharge, securing of minimum discharge in low-water periodsImprovement of groundwater and surface water qualityFlood protectionImprovement of the ecological role of water bodies
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Potential for conflict
AgricultureEnvironment
Landscape waterbalance
Conflicting Objectives
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Approach
1. Calculation of groundwater and surface water levels applying a coupled GW-SW model for different system states
2. Calculation of depth to groundwater using the groundwater levels and a DEM
3. Intersection of depth to groundwater with defined target levels, definition of areas of conflict
4. Simulation of scenarios lowering the potential for conflict, using the target levels as goal for future planning
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FEFLOW
Coupled Model FEFLOW-MIKE11
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Target Compliance, Initial State (March)
too drytoo wetacceptable
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#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
%U
%U
%U
%U
%U
%U
%U
%U
%U
%U
%U
%U
%U
Gabow
Gabow
Paulshof I
ZckerickerLoose/ Oder
ZckerickerLoose/ Dorf
Paulshof II
Zollbrcke
Nasser Polder/Gsteb. L.
Bienwerder
St-01
St-02
St-03
St-04
St-05
St-06
St-07
St-08
St-09
St-10
St-11
St-12
St13
241
301
401
611
631
843
844
211331
701
371
532
842
Neue Stauer
Sohlschwelle%U
Wehr%U
Angepasste Bauwerke
#S
Planned Measures Modification of target water levels for pumping stations Adaptation of structures, change of storage levels Installation of weirs and low weirs (ground sills) Desludging of ditches Closure of Altreetz pumping station
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#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
#S
%U
%U
%U
%U
%U
%U
%U
%U
%U
%U
%U
%U
%U
ZZ
Z
Z
Z
Z
241
301
401
611
631
843
844
211331
701
371
532
842
St-01
St-02
St-03
St-04
St-05
St-06
St-07
St-08
St-09
St-10
St-11
St-12
St13Gabow
Gabow
Paulshof I
ZckerickerLoose/ Oder
ZckerickerLoose/ Dorf
Paulshof II
Zollbrcke
Nasser Polder/Gsteb. L.
Bienwerder
Schpfwerke
Z
Neue Stauer
Sohlschwelle%U
Wehr%U
Angepasste Bauwerke
#S
Mrz (Plan - Ist)[m]
> 0.30.25 - 0.300.20 - 0.250.15 - 0.200.10 - 0.150.05 - 0.10-0.10 - -0.05-0.15 - -0.10-0.20 - -0.15-0.25 - -0.20< -0.25
Entschlammungs-strecken
Predicted Change in Water Level
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SW-Gebiet Paulshof I
0
5
10
15
20
25
30
35
40
45
50
Jan Feb Mrz Apr Mai Jun Jul Aug Sept Okt Nov Dez
Monat
F
l
c
h
e
n
a
n
t
e
i
l
[
%
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Ist-Zustand Plan-Zustand
Target Compliance
PredictedInitialF
r
a
c
t
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o
f
T
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l
A
r
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a
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Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Area Controlled by Pumping Station Paulshof I
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-3500
-3000
-2500
-2000
-1500
-1000
-500
0
500
1000
1500
2000
Zollb
rck
e
Pauls
hof I
Bien
enwe
rder
Gabo
wZ
cker
icker
Loos
e
Pauls
hof II
Nass
er P
older
Altre
etz
SW-Gebiete
D
i
f
f
e
r
e
n
z
(
b
e
r
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t
[
P
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-
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e
m
e
s
s
e
n
[
I
s
t
]
)
[
m
/
d
]
Reduction of pumped water quantity by 8%
~1.7 million m/yr
Modification of Pumping Rates
C
h
a
n
g
e
f
r
o
m
i
n
i
t
i
a
l
p
u
m
p
i
n
g
r
a
t
e
[
m
3
/
d
]
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Cavern Construction for LNG Storage
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Ice RingIce Ring
InsulationInsulation
Stainless Stainless SteelSteel
CavernCavernLNG
-162 C
Principle
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Simulation Objectives
Represent the dewatering process over a 4-year construction period with a complex construction schedule
Inflow/drainage for all parts of the underground structure Impact on groundwater level in the surrounding area Seawater intrusion potential
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Density-dependent variably saturated flow
Advective-dispersive transport of dissolved constituents
Physical Processes
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Model Domain
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Model Domain
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Superelement mesh
253 polygons
463 lines
Spatial Discretization
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Finite-element mesh
956,125 elements
498,914 nodes
Spatial Discretization
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Finite-element mesh Cavern structures
Spatial Discretization
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Finite-element mesh Cavern structures
Spatial Discretization
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Saturated conductivity
Porosity
Granitic Gneiss 10-910-8 m/s 1%
Mica Schist 10-7 m/s 1%
Altered zone 12 x 10-6 m/s 5%
Insulation 10-11 m/s 1%
Material Properties
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Kr = Seff
Seff = (1 + ||-n)-m
= 2
= 0.1 m-1 n = 1.964 m = 0.509
Effective saturation vs. Pressure head
Relative conductivity vs. Effective saturation
Material Properties
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Groundwater recharge
Boundary Conditions
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Flow (Hydraulic head)
Dirichlet condition along coastline
No-flow (zero-value Neumann) condition elsewhere
Transport (Solute concentration)
Dirichlet (fixed-concentration) condition for infiltrating seawater along coastline
Zero-value Neumann condition for fluid leaving domain along coastline
Impermeability condition elsewhere
Boundary Conditions
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Internal surfaces of the structure are treated asSeepage face
Dirichlet condition of fixed atmospheric pressurefor outwarding-pointing head gradient
No-flow (zero-value Neumann) condition otherwise
Boundary Condtions
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Simulation requires successive activation of seepage-face B.C.s as construction progresses.
New B.C.s must continuously be introduced during the simulation.
Solution:
Seepage-face activation via a separate module using the FEFLOW Open Programming Interface:
arbitrary node groups and activation intervals
arbitrary pressure
import capability from ASCII files
saves all information with the problem file
Transient Boundary Conditions
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Steady-state head and solute-concentration distributions obtained for undisturbed conditions
Initial Condition
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0 d0 d 360 d360 d
720 d720 d 1080 d1080 d
Pressure
Simulation Results
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Pressure
0 d
360 d
720 d
1080 d
Simulation Results
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Solute concentration
Simulation Results
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Groundwater table
Simulation Results