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The Hydrodynamic Characteristics Calculus for Isolated Profile Go428
using Solidworks Flow Simulation Module
DORIAN NEDELCU
DRAGHITA IANICI
Department of Materials Engineering, Mechanical and Industrial
„Eftimie Murgu” University of Resita
P-ta Traian Vuia 1-4, 320085 Resita
ROMANIA
MARIAN-DUMITRU NEDELONI
DANIEL DAIA
FLORENTIN MIREL POP
RAOUL CRISTIAN AVASILOAIE
Department of Engineering Faculty
„Eftimie Murgu” University of Resita
P-ta Traian Vuia 1-4, 320085 Resita
ROMANIA
Abstract: - The objective of the application is to determine, through SolidWorks Flow Simulation module, the
drag coefficient and the lift coefficient of the Go428 profile, for various values of the incidence attack angle α∞. The isolated profile Go428 is immersed in a uniform air stream, oriented perpendicular to the stream. The
velocity of the air stream is V∞=2 m/s and water density is ρ=998.2 kg/m3. Finally, the results predicted by 2D
simulation will be compared with experimental data.
Key-Words: - drag coefficient, lift coefficient, SolidWorks, Flow Simulation
1 Introduction The application’s goal is to calculate the
hydrodynamic characteristics (drag coefficient and
the lift coefficient) resulting from the isolated profile
Go 428 and fluid interaction, fig. 1, for different values
of the incidence attack angle α∞. The water velocity is
V∞=2 m/s. The profile chord is L=305 mm and the
width of the wing is B=1525 mm. The coordinates of
the Go 428 profile are presented in tab. 1, where: X is
the abscissa and YE/YI are Y values for
suction/pressure side. The origin of the coordinate
system is placed in the leading edge point BA with X
axis positive oriented to the trailing edge point BF and
Y axis perpendicular in the BA point.
Fig. 1
Proceedings of the 4th WSEAS International Conference on Finite Differences - Finite Elements - Finite Volumes - Boundary Elements
ISBN: 978-960-474-298-1 92
Tab. 1
X YE YI
mm mm mm
305 0 0
289.75 3.538 0.793
274.5 6.771 1.586
244 12.322 2.867
213.5 17.568 4.148
183 21.899 5.124
152.5 25.315 5.185
122 27.206 4.636
91.5 27.572 3.477
61 25.498 1.708
45.75 22.631 0.671
30.5 18.544 -0.976
22.875 15.738 -1.647
15.25 12.627 -2.013
7.625 7.991 -2.074
3.8125 5.2155 -1.7995
0 0 0
2 Problem Formulation
The force F , which is perpendicular on the profile
chord, is the resultant force between the drag force xF
and lift force yF , calculated by the following
relations:
BLV
CFxx
⋅= ∞
2
2
ρ (1)
BLV
CFyy
⋅= ∞
2
2
ρ (2)
The Cx and Cy coefficients of (1) and (2) relations
are determined experimentally for various values of
the incidence attack angle α∞ and the ratio LB /=λ .
The Cy lift coefficient is negative for negative
incidence angles, became zero for null lift angle α∞o,
than grow almost linear until the critical incidence
angle, with values between 10o și 15
o; then, the lift
coefficient decrease and the drag coefficient grow. For
the ratio 5305/1525/ === LBλ , the
experimental curves of the lift and drag coefficients are
presented numeric in tab. 2 and graphic in fig. 2 [1].
Tab. 2
α∞ -8.9 -6 -4.5 -3 -1.6 -0.1
Cx 0.0795 0.0301 0.015 0.0124 0.0132 0.0157
Cy -0.322 -0.089 0.011 0.103 0.205 0.302
α∞ 1.3 2.8 4.3 5.7 8.7 11.6
Cx 0.0184 0.0246 0.0328 0.0423 0.0662 0.0944
Cy 0.402 0.506 0.608 0.704 0.884 1
Profile Go 428
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
-10 -5 0 5 10 15
αααα οοοοοοοο [grd]
Cx, Cy [-]
Cy Experimental
Cx Experimental
Fig. 2
3 The stages of application o The profile and wing design;
o Activation of the Flow Simulation module;
o Create Flow Simulation project;
o Define Computational Domain and goals;
o Running flow study;
o View the results;
o Cloning the project;
o Modify the α∞ incidence attack angle and
rerun the study;
o Simulation and experimental results
comparison.
3.1 The profile and wing design The Go428 profile coordinates will be imported from “txt” file into SolidWorks file creating a curve entity; this curve will be converted into a block; the block will be inserted in the file at incidence attack angle α∞ and extruded to create the wing.
• Create a new part document and save it as
Go428.
• Create data file profile.
A text file „XYZ Go428.txt” with the profile
coordinates should be created as plain text with
dimensions in mm and have the “txt” file extension.
The easy ways to manipulate profile coordinates is to
use Excel software and then export as text. The last
point in the profile coordinates must be the same as the
first one, so that the coordinates form a loop. The file
will contain the (X,Y,Z) profile coordinates, where X
Y are the values from tab. 1 and Z=0. The coordinates
are separated by spaces.
• Import coordinates into SolidWorks through
Curve Through XYZ Points command,
which will create Curve1 entity.
• Create the block profile through Make
block command.
By creating block entity, this will loose the connection
with Curve1 entity and can be repeatedly inserted into
the file at any point and incidence angle.
Proceedings of the 4th WSEAS International Conference on Finite Differences - Finite Elements - Finite Volumes - Boundary Elements
ISBN: 978-960-474-298-1 93
• Insert the block profile through Insert block
command, which require the block rotation
angle and the block origin point. The block
profile will be placed at incidence attack angle
α∞ from tab. 2. The block origin (the BF point
of the profile) will be placed in the coordinate
system origin.
• Through Boss-Extrude command, the
block profile will be symmetric extruded on
total distance 1525 mm.
3.2 Activation of the SolidWorks Flow
Simulation module Flow Simulation is based on advanced
Computational Fluid Dynamics (CFD) techniques and is created to analyze a wide range of complex problems including [2]:
o 2D and 3D dimensional analyses;
o External and Internal flows;
o Steady-state and Transient flows;
o Incompressible liquid and Compressible gas
flows including subsonic, transonic, and
supersonic regimes;
o Water vapour (steam) condensation;
o Calculation of relative humidity in gas flows
o Non-Newtonian liquids (laminar only);
o Compressible liquids (liquid density is
dependent on pressure);
o Real gases;
o Laminar, turbulent, and transitional flows;
o Swirling flows and Fans;
o Multi-species flows;
o Flows with heat transfer within and between
fluids and solids;
o Flows in a rotating device (global rotating
frame of reference) or in local regions of
rotation;
o Cavitation.
Once installed, SolidWorks Flow Simulation module
can be activated inside SolidWorks using Tools→
Add-Ins menu; as a consequence, the Flow Simulation
menu bar will be added to the main menu.
3.3 Create Flow Simulation project A Flow Simulation project contains all the settings
and results of a problem. Each project is associated
with a SolidWorks configuration. By modifying a
Flow Simulation project it is possible to analyze
flows under various conditions and for modified
SolidWorks models. When a basic project has been
created, a new Flow Simulation Design Tree tab
appears on the side of the SolidWorks Configuration
Manager tab.
For this application, the main project characteristics
are: SI unit system, External flow, Water fluid, 2 m/s
velocity in X direction.
3.4 Define Computational Domain The flow and heat transfer calculations are
performed inside the computational domain. Flow Simulation analyzes the model geometry and automatically generates a Computational Domain in the shape of a rectangular prism enclosing the model. The computational domain’s boundary planes are orthogonal to the model’s Global Coordinate System axes. For External flows, the computational domain’s boundary planes are automatically distanced from the model. In this application, to reduce the required CPU time and computer memory, will perform a two-dimensional (2D) analysis. To access the Computational Domain dialog, click Flow
Simulation→Computational Domain, and specify 2D flow and the following values: X+/- 1 m, Y+/- 0.5 m, Z+/- 0.7625 m, fig. 3.
Fig. 3
For most cases, to study the flow field around an
external body and to investigate the effects of design
changes it is recommended to use the default
Computational Domain size as determined by Flow
Simulation. However, in this case we will compare the
Flow Simulation results to experimental results and we
would like to determine the lift and drag coefficient
with a high degree of accuracy. In order to eliminate
any disturbances of the incoming flow at the
Computational Domain boundaries due to the presence
of the wing, we will manually set the boundaries
farther away from the wing [3]. The accuracy will be
increased at the expense of required CPU time and
memory due to the larger size of Computational
Domain.
3.5 Define goals Flow Simulation initially considers any steady state
flow problem as a time-dependent problem. The solver
module iterates on an internally determined time step
Proceedings of the 4th WSEAS International Conference on Finite Differences - Finite Elements - Finite Volumes - Boundary Elements
ISBN: 978-960-474-298-1 94
to seek a steady state flow field, so it is necessary to
have a criterion of determining that a steady state flow
field is obtained, in order to stop the calculations. Flow
Simulation contains built-in criteria to stop the solution
process, but it is best to use specific criteria, which are
named Goals. It is possible to set the following type of
goals: global, point, surface, volume and equation [4]. For this application both the X - Component of Force and Y - Component of Force were specified as a Global Goal. This ensures that the calculation will not be finished until both components, in the entire computational domain, are fully converged. Also, the following two equation goals were imposed:
{GG X - Component of Force}/(0.5*998.2*2^2*1.5*0.305) (3)
{GG Y - Component of Force}/(0.5*998.2*2^2*1.5*0.305) (4)
to obtain the numerical values of the drag and lift
coefficient at the end calculation. The expressions
were obtained by extraction of the Cx and Cy
coefficients from relations (1) and (2), with the
following values:
o 998.2 kg/m3 – the water density;
o 2 m/s – the fluid velocity in X direction;
o 1.5 m – the wing width;
o 0.305 m – the length chord of the profile.
3.6 Running flow study: The Flow Simulation → Solve → Run command
start the calculation. Flow Simulation automatically
generates a computational mesh, by dividing the
computational domain into slices, which are further
subdivided into cells. The cells are refined as
necessary to properly resolve the model geometry.
After the calculation starts, the Solver Monitor dialog,
fig. 4, provides informations about the current status
of the solution, by monitoring the goal changes and
view preliminary results at selected planes. In the
bottom pane of the Info window Flow Simulation
notifies with messages if inappropriate results may
occur.
Fig. 4
3.7 View the results When the calculation is finished, the flow
parameters distribution can be seen and analyzed the
results with various results processing features and
tools available in Flow Simulation: Cut Plot, Surface
Plot, Isosurfaces, Flow Trajectories, Particle Study,
Surface Parameters, Volume Parameters, Point
Parameters, XY Plot, Goal Plot, Report, Animation.
The Goal Plot offer the possibility to study how
the goal value changed in the course of calculation.
Flow Simulation uses Microsoft Excel to display goal
plot data. The goal plot evolution is displayed
numerical and graphical in Excel sheets; fig. 6 show
the Goal Plot for incidence attack angle α∞=5.7o.
The converged values of all project goals are displayed
in the Summary sheet and numerical values are
placed in Plot Data sheet of an automatically created
Excel workbook, fig. 6. This summary contain the
numerical results of all imposed goals: X -
Component of Force, Y - Component of Force,
LIFT and DRAG coefficients, calculated with rel. (3)
and (4).
Go428.SLDPRT [5.7 grade]
-0.1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0 20 40 60 80 100 120
Iterations
LIFT & DRAG
COEFFICIENT
LIFT Coefficient
DRAG Coefficient
Fig. 5
Fig. 6
The Cut Plot displays results of a selected
parameter in a selected view section. To define the
view section, can be used SolidWorks planes or model
planar faces (with the additional shift if necessary).
The parameter values can be represented as a contour
plot, as isolines, as vectors, or in a combination (e.g.
contours with overlaid vectors). Fig. 7 show the Cut
Plot velocity distribution for incidence attack angle α∞=5.7
o.
Proceedings of the 4th WSEAS International Conference on Finite Differences - Finite Elements - Finite Volumes - Boundary Elements
ISBN: 978-960-474-298-1 95
Fig. 7
Using Flow trajectories it is possible to view the
flow streamlines. Flow trajectories provide a very
good image of the 3D fluid flow, show how
parameters change along each trajectory by exporting
data into Microsoft Excel and save trajectories as
SolidWorks reference curves. Fig. 8 show the Flow
trajectories pressure distribution for incidence attack
angle α∞=5.7o.
Fig. 8
3.8 Cloning the project In the first project, the profile was placed at 5.7
o
incidence angle. This project will multiplied by cloning, to place the profile at all incidence angles from tab. 2. The two components: the drag and lift coefficients, will be calculated for every angle case. After the α∞ incidence attack angle changes the study must be rerun.
4 Simulation and experimental results
comparison The Excel values from Goal Plot option was
centralized in the tab. 3 and tab. 4, for all values of the α∞ angle. The diagram from fig. 9 show a comparison between the Flow Simulation and experimental values of the drag and lift coefficients.
Tab. 3
Experimental Flow Simulation α∞
Cy Cx Cy Cx
-8.9 -0.322 0.0795 -0.209 0.086
-6 -0.089 0.0301 -0.146 0.060
-4.5 0.011 0.015 -0.017 0.046
-3 0.103 0.0124 0.113 0.034
-1.6 0.205 0.0132 0.218 0.027
-0.1 0.302 0.0157 0.323 0.024
1.3 0.402 0.0184 0.425 0.028
2.8 0.506 0.0246 0.514 0.035
4.3 0.608 0.0328 0.611 0.042
5.7 0.704 0.0423 0.682 0.051
8.7 0.884 0.0662 0.877 0.083
11.6 1 0.0944 1.025 0.115
Tab. 4
Experimental Flow Simulation α∞
Fy Fx Fy Fx
grd N N N N
-8.9 -299.0 73.8 -190.5 78.1
-6 -82.6 28.0 -133.1 54.8
-4.5 10.2 13.9 -15.6 42.1
-3 95.6 11.5 103.7 30.8
-1.6 190.4 12.3 198.9 25.0
-0.1 280.4 14.6 295.2 21.5
1.3 373.3 17.1 387.9 25.8
2.8 469.9 22.8 469.7 32.0
4.3 564.6 30.5 558.5 38.4
5.7 653.7 39.3 623.1 46.6
8.7 820.9 61.5 800.9 76.2
11.6 928.6 87.7 936.6 105.2
Profile Go 428
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
-10 -8 -6 -4 -2 0 2 4 6 8 10 12
αααα οοοοοοοο [grd]
Cx, Cy [-]
Cy Experimental
Cy Flow Simulation
Cx Experimental
Cx Flow Simulation
Fig. 9
Proceedings of the 4th WSEAS International Conference on Finite Differences - Finite Elements - Finite Volumes - Boundary Elements
ISBN: 978-960-474-298-1 96
The fig. 10 and 11 show the pressure and velocity
distribution calculated by SolidWorks Flow
Simulation, for the following angles: -8.9, -4.5, -1.6,
+1.3, +4.3 and +8.7 grd.
Fig. 10
Fig. 11
The fig. 12 show the pressure distribution
calculated by SolidWorks Flow Simulation, for the
following angles: -1.6, +4.3 and +8.7 grd.
5 Conclusion The curves from fig. 9 and tab. 3, 4 confirms a very
good coincidence between calculated and
experimental values of the Go428 hydrodynamic
characteristics profile, except one point on the left
incidence angle domain, where the difference is
greater. Such type of profiles are used to design the
blade of the Kaplan runner [5]. The results were
obtained without great computational efforts, since the
number of the generated finite elements were situated
between 19000 and 32000 and the CPU time was
about 3…6 minutes per angle, for a computer with 2
GB RAM memory and 1.86 GHz Intel Core 2
processor.
Pressure distribution Go428
98500
99500
100500
101500
102500
103500
-0.35 -0.3 -0.25 -0.2 -0.15 -0.1 -0.05 0
Model X (m)
Pressure (Pa)
8.7 grd
4.3 grd
-1.6 grd
Fig. 12
Acknowledgements The authors gratefully acknowledge the support of
the Managing Authority for Sectoral Operational
Programme for Human Resources Development
(MASOPHRD), within the Romanian Ministry of
Labour, Family and Equal Opportunities by co-
financing the project “Excellence in research
through postdoctoral programmes in priority
domains of the knowledge-based society (EXCEL)”
ID 62557 and “Investment in Research-innovation-
development for the future (DocInvest)” ID 76813.
References:
[1] V. Dobânda, Catalog de profile
aerohidrodinamice al LMHT, Vol.1, IPTVT,
1985, pp. 51-51.
[2] Dassault Systems, SolidWorks Flow Simulation
2010 Technical Reference, 2010, pp. 1-2.
[3] Dassault Systems, SolidWorks Flow Simulation
Tutorial 2010, 2010, pp. 5-6.
[4] Dassault Systems, Flow Simulation 2010
Online User’s Guide, 2010. [5] Doina Frunzaverde, Viorel Campian, Dorian
Nedelcu, Gilbert-Rainer Gillich, Gabriela
Marginean, Failure Analysis of a Kaplan
Turbine Runner Blade by Metallographic and
Numerical Methods, 2010 WSEAS
Conferences, University of Cambridge,
February 2010.
Proceedings of the 4th WSEAS International Conference on Finite Differences - Finite Elements - Finite Volumes - Boundary Elements
ISBN: 978-960-474-298-1 97