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© 2010 Mentor Graphics Corp. Company Confidentialwww.mentor.com
FloEFD Validation and Software Test Matrix
Before the release of each version of FloEFD a suite of 300 test cases are run through the different CAD embedded versions of the software
The test matrix ranges from simple 2D tests to industrial scale 3D benchmarks (see the following slides for a sample set of FloEFD validations)
The validation suite includes many classical CFD benchmark cases including a wide range of flow turbulence scenarios and regimes suitable for a General Purpose CFD code
The following slides illustrate some of the benchmarks each FloEFD release has to meet.
© 2010 Mentor Graphics Corp. Company Confidentialwww.mentor.com
0
5
10
15
0 0.2 0.4 0.6 0.8 1
Y (mm)
X/LR
separationstreamlines,calculation
vortexcenter,calculation
Resistance
Velocity profiles
Recirculation zone
FloEFD Validation: Flow in 2D Channels with bilateral and unilateral expansions (Backward Facing Steps)
1
1Idelchik, I.E., Handbook of Hydraulic Resistance.2nd ed., McGraw Hill, New York, 1979
00.10.20.30.40.50.60.70.80.9
1
0.0 0.2 0.4 0.6 0.8 1.0
s
A0/A1
theoryEFD.Lab
1
2
2Yanshin, B.I.: Hydrodynamic Characteristics of Pipeline Valves and Elements. Convergen Sections, Divergent Sections and Valves. “Mashinostroenie”, Moscow, 1965
FloEFD
© 2010 Mentor Graphics Corp. Company Confidentialwww.mentor.com
T VX VY Streamlines
Nusselt number vs. Rayleigh number
0123456789
10
1.E+03 1.E+04 1.E+05 1.E+06
Nuav
Ra
Refs.10,11
Ref.12
EFD.Lab
FloEFD Validation: Natural Convection in a Square Cavity
Dimensionless Velocities vs. Rayleigh Number
References10 Davis, G. De Vahl; Jones, I.P.: Natural Convection in a Square Cavity: a Comparison Exercise. Int. J. for Num. Meth. In Fluids, v.3, pp. 227-248 (1983)11 Emery, A., Chu, T.Y.: Heat Transfer across Vertical Layers. J. Heat Transfer, v. 87, p. 110 (1965)12 Denham, M.K., Patrick M.A.: Laminar Flow over a Downstream Facing Step in a Two-Dimensional Flow Channel. Trans. Instn. Chem. Engrs., v. 52, pp. 361-367 (1974)
FloEFD
© 2010 Mentor Graphics Corp. Company Confidentialwww.mentor.com
FloEFD Validation: Couette Flow between Parallel Flat Plates at Re = 3.4 x 104
A classical plane flow is one between two parallel infinite flat plates spaced at a distance h from one another and moving at velocity U in opposite directions ,
Dimensionless velocity profiles for different meshes (10, 20, 40, 80 mesh cells across the channel) compare well with experimental data illustrating that with relatively coarse meshes good predictions can be expected when using FloEFD.
h
y
x
u(y)
U
-U
-1.0-0.8-0.6-0.4-0.20.00.20.40.60.81.0
-1.0 -0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0
u/U
y/(h/2)
experiment (Ref.9)FloEFD, 10 cellsFloEFD, 20 cellsFloEFD, 40 cellsFloEFD, 80 cells
References1. Schlichting, H. Boundary-Layer Theory. McGraw-Hill, New York, 1979.
1)
© 2010 Mentor Graphics Corp. Company Confidentialwww.mentor.com
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06 1.E+07 Re
Sh
0.1
1
10
100
1000
1.E-01 1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06
ReD
NuD Calculation, steady-state
Calculation, time-dependent
Flow Trajectories over and past a Circular Cylinder at Re=41:Qualitative Comparison with Experiment (Ref 9)
Strouhal Number vs. Reynolds Number (Ref 4) Drag Coefficient vs. Reynolds Number (Ref 3)
Nusselt Number vs. Reynolds Number(Ref 6)
FloEFD Validation: Flow and Heat Transfer over a Circular Cylinder for Low Reynolds Numbers
References3. Panton, R.L., Incompressible Flow. 2nd ed., John Wiley & Sons, Inc., 19964. White, F.M., Fluid Mechanics. 3rd ed., McGraw-Hill, New York, 19946. Holman, J.P., Heat Transfer. 8th ed., McGraw-Hill, New York, 19979. Davis, G. De Vahl: Natural Convection of Air in a Square Cavity: a Bench Mark Numerical Solution. Int. J. for Num. Meth. In Fluids, v. 3, pp. 249-264 (1983)
© 2010 Mentor Graphics Corp. Company Confidentialwww.mentor.com
FloEFD Validation: Unsteady Vortex Shedding Flow over a Circular Cylinder at Re=3.7x105
Mesh Density(cells per cylinder
diameter)
Deviation from experimental data
(%)
FloEFD, 20 cells per diameter 0.82 -18 650
FloEFD, 40 cells per diameter 0.95 -5 330
FloEFD, 80 cells per diameter 1.02 2 170
Experiment (Driver and Seegmiller 1985) 1.0 n/a n/a
dC maxy
Driver, D.M. and Seegmiller, H.L. (1985). Features of a Reattaching Turbulent Shear Layer in Divergent Channel Flow. AIAA Journal, Vol. 23, p. 163.
Predicted turbulent transient flow velocity fields over a circular cylinder calculated with FloEFDfor different computational meshes having:
a) 20 quad cells per diameter, b) 40 quad cells per diameter,c) 80 quad cells per diameter, &d) Similar real flow shadowgraph from
Driver and Seegmiller (1985)
Circular cylinder drag coefficients calculated with FloEFD in comparison with experimental data (Driver and Seegmiller1985).
© 2010 Mentor Graphics Corp. Company Confidentialwww.mentor.com
Mach number distribution
Classical benchmark of air flow at inlet M=3 in a 2D (planar) convergent-divergent channel
FloEFD Validation: Supersonic Flow in a 2-D Convergent-Divergent Channel
ReferencePoint
1 2 3 4 5
X ordinate (m) 0.0042 0.047 0.1094 0.155 0.1648
Y ordinate (m) 0.0175 0.0157 0.026 0.026 0.0157
Mach Number (Theory)
3.000 2.427 1.957 2.089 2.365
Mach Number(FloEFD)
3.000 2.429 1.965 2.106 2.380
Difference (%) 0.0 0.1 0.4 0.8 0.6
© 2010 Mentor Graphics Corp. Company Confidentialwww.mentor.com
FloEFD Validation: Smoothing step-shaped velocity profile by a porous screen of different drag coefficient ( ζ )
References2. Panton, R.L., Incompressible Flow. 2nd ed., John Wiley & Sons, Inc., 1996
© 2010 Mentor Graphics Corp. Company Confidentialwww.mentor.com
Flow Streamlines: Smoke Visualisation, left (Ref 19), FloEFD result, right
43 / (Ref 14)
41 /
FloEFD Validation: Cooling a Pin-Fin Heat Sink Due to Natural Convection
References14. Enchao Yu, Yogendra Yoshi: Heat Transfer Enhancement from Enclosed Discrete Components using Pin-Fin Heat Sinks Int. J. of Heat & Mass Transfer, v. 45, pp. 4957-4966 (2002)19. Jyotsna, R., Vanka, S.P.: Multigrid Calculation of Steady, Viscous Flow in a Triangular Cavity. J. Comput. Phsy., v. 122, pp. 107-117 (1995)
© 2010 Mentor Graphics Corp. Company Confidentialwww.mentor.com
Caviatition on a Hydrofoil (1); QuantitativeComparison
Cavitation Number,
Pressure Coefficient vs. Cavitation NumberCavitation Length vs. Cavitation Number
© 2010 Mentor Graphics Corp. Company Confidentialwww.mentor.com
V=8 m/s, Chord length = 0.305 m
Angle of attack () – 3.5о
Cavitation number,
Caviatition on a Hydrofoil (2); QualitativeComparison
Reference
24. Wesley, H.B., Spyros, A.K.: Experimental & Computational Investigation of Sheet Cavitationon a Hydrofoil. Presented at 2nd Joint ASME/JSME Fluid Engineering Conference & ASME/EALA 6th
International Conference on Laser Anemometry. The Westin Resort, Hilton Head Island, SC, USA August 13-18, 1995
© 2010 Mentor Graphics Corp. Company Confidentialwww.mentor.com
Component Mass Fraction, %
Fuel (Methane) 3.29
Oxidizer (Air) 96.71
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R/D
Tem
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ture
(K)
CalculationExperimental measurement 1
Experimental measurement 2
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400
800
1200
1600
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R/D
Tem
pera
ture
(K)
Calculation Experimental measurement 1
Experimental measurement 2
Reference
27. Nandula, S.P., Pitz, R.W., Barlow, R.S., Fiechtner, G.J., Rayleigh/Raman/LIF Measurements in a Turbulent Lean Premixed Combustor” AIAA 96-0937, 34th Aerospace Sciences Meeting & Exhibit, Reno, NV, January 15-18, 1996
Combustion of a Premixed Methane/Air Mixture
© 2010 Mentor Graphics Corp. Company Confidentialwww.mentor.com
FloEFD Validation: Flow in a 90o-bend of a 3D square duct
Velocity profiles at different cross sections in different longitudinal planes
AA1
AA1
Reference8. Van Dyke, Milton, An Album of Fluid Motion. The Parabolic Press, Stanford, California, 1982.
© 2010 Mentor Graphics Corp. Company Confidentialwww.mentor.com
Hydraulic resistance coefficient Torque coefficient
Flow through a Cone Valve
Reference13. Yanshin, B.I.: Hydrodynamic Characteristics of Pipeline Valves and Elements.Convergent Sections, Divergent Sections, and Valves. “Mashinostroenie”, Moscow,1965.
© 2010 Mentor Graphics Corp. Company Confidentialwww.mentor.com
-1-0.8-0.6-0.4-0.2
00.20.40.60.8
11.21.41.6
0 30 60 90 120 150 180
Ct, Cn
Attack angle, degree
Ct, experimetCt, EFD.LabCn, experimentCn, EFD.Lab
-0.04
-0.02
0
0.02
0.04
0.06
0.08
0 30 60 90 120 150 180
mz
Attack angle (degree)
Experiment
Calculation
Aerodynamic drag coefficient vs. attack angleAerodynamic torque coefficient vs. attack angle
Supersonic air flow at incident M=1.3 over a segmental conic body at different attack angles in the 0…180° range.
Supersonic Flow over a Segmental Conic Body
Reference5. Artonkin, V.G., Petrov, K.P., Investigations of aerodynamic characteristics ofsegmental conic bodies. TsAGI Proceedings, No. 1361, Moscow, 1971 (in Russian).
© 2010 Mentor Graphics Corp. Company Confidentialwww.mentor.com
Flow Around the Ahmed Car Body
Slant angle = 35°
0
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200
300
400
500
600
700
800
-1600 -1400 -1200 -1000 -800 -600 -400 -200 0 200 400 600 800
x, mm
z, m
m
ReferenceLienhart, H., Stoots, C., Becker, S. Flow and turbulence structures in the wake of a
simplified car model (Ahmed model). DGLR Fach Symp. der AG STAB, Stuttgart University, 2000.
AhmedBody Slant Angle
AbsoluteDifference
% Difference
25° 0.298 0.284 -0.014 -4.8
35° 0.257 0.274 0.017 6.6
© 2010 Mentor Graphics Corp. Company Confidentialwww.mentor.com
Injection of a particle into a uniform fluid flow field:
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0 0.05 0.1 0.15 0.2 0.25
y, m
x, m
EFD.Lab
analytical solution
Re = 0.1
0.00
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0.10
0.00 0.05 0.10 0.15 0.20 X, m
Vp = 1 m/s,analytical solutionVp = 1 m/s,EFD.LabVp = 2 m/s,analytical solutionVp = 2 m/s,EFD.LabVp = 3 m/s,analytical solutionVp = 3 m/s,EFD.Lab
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.00 0.03 0.06 0.09 0.12 0.15 X, m
EFD.Lab
Re = 105
Particle trajectory in the Y-direction gravity
Dispersed-phase flows (droplets and solid particles’ trajectories)
Reference18. Henderson, C.B. Drag Coefficients of Spheres in Continuum and Rarefied Flows.AIAA Journal, v.14, No.6, 1976.
© 2010 Mentor Graphics Corp. Company Confidentialwww.mentor.com
Comparison of predicted and measured total pressure drop for a Stairmand HE cyclone
0
500
1000
1500
2000
2500
3000
0 5 10 15 20 25 30
U inlet, m/s
dP, P
a
ExperimentEFD calculations
Time evolution of the total pressure drop of a Stairmand HE cyclone at 10 m/s gas inlet velocity
0
100
200
300
400
0.3 0.7 1.1 1.5 1.9
Time, s
dP, P
a
Experiment
EFD calculation
Stairmand High Efficiency Gas Cyclone (Non-isotropic swirling Flows)
Reference Griffiths, W.D., Boysan, F., 1996, “Computational fluid dynamics (CFD) and empirical modellingof the performance of a number of cyclone samplers”, J. Aerosol Sci, Vol 27, №2, 281-304
© 2010 Mentor Graphics Corp. Company Confidentialwww.mentor.com
Reference
Winklhofer, E., Kull, E., Kelz, E., and Morozov, A., 2001, “Comprehensive Hydraulic and Flow Field Documentation in Model Throttle Experiments Under Cavitation Conditions.” ILASS Europe 2001.
L=0.001 m, H=0.000299 m,
W=0.0003 m, Rin=0.00002 m
100 bar
33 bar
100 bar
100 bar
25 bar
15 bar
Mass flow rate through the injector versus pressure drop
0.004
0.005
0.006
0.007
0.008
0.009
20 30 40 50 60 70 80 90 100
(Pin - Pb), bar
G, k
g/s
calculationexperiment
Fuel Injector Cavitation
Inlet
Outlet
Nozzle Wall
© 2010 Mentor Graphics Corp. Company Confidentialwww.mentor.com
Modified equilibrium combustion model approach in FloEFD:— Combustion starts upon mixing (no pre-mixing)— “Limited Combustion Rate” option when
premixed. Requires the separate simulation of an igniter to start the combustion simulation
FloEFD Validation: Vortex Combustor Benchmark
600
800
1000
1200
1400
1600
1800
2000
0 0.1 0.2 0.3 0.4 0.5 0.6
Position [m]
Tem
pera
ture
of F
luid
[K
]
X=0.027
ReferenceSayre A, N. Lallemant, J. Dugue, R. Weber, 1994, Scaling Characteristics of Aerodynamics and Low-NOx Properties of Industrial Natural Gas Burners, The Scaling 400 Study, Part IV: The 300 kW BERL Test Results, IFRF Doc No F40/y/11, The Netherlands.