The computational grid is presented in the Part 1.
Solver: simpleFoam
Wind speed: 60m/s
Turbulent intensity at inlet: 0.5%
Turbulence model: realizableKE
Div scheme: Gamma NVD scheme
controlDict:
application simpleFoam;
startFrom latestTime;
startTime 0;
stopAt endTime;
endTime 10000;
deltaT 1;
writeControl adjustableRunTime;
writeInterval 100;
purgeWrite 0;
writeFormat ascii;
writePrecision 7;
writeCompression off;
timeFormat general;
timePrecision 6;
runTimeModifiable true;
functions
{
fieldMinMax
{
type fieldMinMax;
functionObjectLibs ("libfieldFunctionObjects.so");
enabled true;
outputControl timeStep;
outputInterval 1;
log true;
mode magnitude;
fields
(
U p
);
}
forces
{
type forces;
functionObjectLibs ("libforces.so");
outputControl timeStep;
outputInterval 1;
patches ("ahmed.*");
pName p;
UName U;
rhoName rhoInf;
log true;
CofR (0 0 0);
rhoInf 1.225;
}
}
Solver: simpleFoam
Wind speed: 60m/s
Turbulent intensity at inlet: 0.5%
Turbulence model: realizableKE
Div scheme: Gamma NVD scheme
controlDict:
application simpleFoam;
startFrom latestTime;
startTime 0;
stopAt endTime;
endTime 10000;
deltaT 1;
writeControl adjustableRunTime;
writeInterval 100;
purgeWrite 0;
writeFormat ascii;
writePrecision 7;
writeCompression off;
timeFormat general;
timePrecision 6;
runTimeModifiable true;
functions
{
fieldMinMax
{
type fieldMinMax;
functionObjectLibs ("libfieldFunctionObjects.so");
enabled true;
outputControl timeStep;
outputInterval 1;
log true;
mode magnitude;
fields
(
U p
);
}
forces
{
type forces;
functionObjectLibs ("libforces.so");
outputControl timeStep;
outputInterval 1;
patches ("ahmed.*");
pName p;
UName U;
rhoName rhoInf;
log true;
CofR (0 0 0);
rhoInf 1.225;
}
}
fvSchemes:
ddtSchemes
{
default steadyState;
}
gradSchemes
{
default cellLimited Gauss linear 0.333;
}
divSchemes
{
default none;
div(phi,U) bounded Gauss GammaV 1;
div(phi,k) bounded Gauss Gamma 1;
div(phi,epsilon) bounded Gauss Gamma 1;
div((nuEff*dev(T(grad(U))))) Gauss linear;
}
laplacianSchemes
{
default Gauss linear limited 0.333;
}
interpolationSchemes
{
default linear;
}
snGradSchemes
{
default limited 0.333;
}
fluxRequired
{
default no;
p ;
}
{
default steadyState;
}
gradSchemes
{
default cellLimited Gauss linear 0.333;
}
divSchemes
{
default none;
div(phi,U) bounded Gauss GammaV 1;
div(phi,k) bounded Gauss Gamma 1;
div(phi,epsilon) bounded Gauss Gamma 1;
div((nuEff*dev(T(grad(U))))) Gauss linear;
}
laplacianSchemes
{
default Gauss linear limited 0.333;
}
interpolationSchemes
{
default linear;
}
snGradSchemes
{
default limited 0.333;
}
fluxRequired
{
default no;
p ;
}
fvSolution:
solvers
{
"p.*"
{
solver GAMG;
tolerance 1e-8;
relTol 0;
smoother GaussSeidel;
nPreSweeps 0;
nPostSweeps 2;
cacheAgglomeration true;
nCellsInCoarsestLevel 10;
agglomerator faceAreaPair;
mergeLevels 1;
}
"(U.*|k.*|epsilon.*)"
{
solver smoothSolver;
smoother GaussSeidel;
tolerance 1e-8;
relTol 0;
nSweeps 1;
}
}
SIMPLE
{
nNonOrthogonalCorrectors 2;
pRefCell 0;
pRefValue 0;
}
relaxationFactors
{
fields
{
p 0.3;
}
equations
{
U 0.7;
k 0.7;
epsilon 0.7;
}
}
{
"p.*"
{
solver GAMG;
tolerance 1e-8;
relTol 0;
smoother GaussSeidel;
nPreSweeps 0;
nPostSweeps 2;
cacheAgglomeration true;
nCellsInCoarsestLevel 10;
agglomerator faceAreaPair;
mergeLevels 1;
}
"(U.*|k.*|epsilon.*)"
{
solver smoothSolver;
smoother GaussSeidel;
tolerance 1e-8;
relTol 0;
nSweeps 1;
}
}
SIMPLE
{
nNonOrthogonalCorrectors 2;
pRefCell 0;
pRefValue 0;
}
relaxationFactors
{
fields
{
p 0.3;
}
equations
{
U 0.7;
k 0.7;
epsilon 0.7;
}
}
RASProperties:
RASModel realizableKE;
turbulence on;
printCoeffs on;
turbulence on;
printCoeffs on;
U:
dimensions [0 1 -1 0 0 0 0];
internalField uniform (60 0 0);
boundaryField
{
inlet
{
type fixedValue;
value uniform (60 0 0);
}
outlet
{
type zeroGradient;
}
side
{
type slip;
}
"ahmed.*"
{
type fixedValue;
value uniform (0 0 0);
}
stilts
{
type fixedValue;
value uniform (0 0 0);
}
ground
{
type fixedValue;
value uniform (0 0 0);
}
}
internalField uniform (60 0 0);
boundaryField
{
inlet
{
type fixedValue;
value uniform (60 0 0);
}
outlet
{
type zeroGradient;
}
side
{
type slip;
}
"ahmed.*"
{
type fixedValue;
value uniform (0 0 0);
}
stilts
{
type fixedValue;
value uniform (0 0 0);
}
ground
{
type fixedValue;
value uniform (0 0 0);
}
}
p:
dimensions [0 2 -2 0 0 0 0];
internalField uniform 0;
boundaryField
{
inlet
{
type zeroGradient;
}
outlet
{
type fixedValue;
value uniform 0;
}
side
{
type slip;
}
"ahmed.*"
{
type zeroGradient;
}
stilts
{
type zeroGradient;
}
ground
{
type zeroGradient;
}
}
internalField uniform 0;
boundaryField
{
inlet
{
type zeroGradient;
}
outlet
{
type fixedValue;
value uniform 0;
}
side
{
type slip;
}
"ahmed.*"
{
type zeroGradient;
}
stilts
{
type zeroGradient;
}
ground
{
type zeroGradient;
}
}
k:
dimensions [0 2 -2 0 0];
internalField uniform 0.135;
boundaryField
{
inlet
{
type fixedValue;
value uniform 0.135;
}
outlet
{
type zeroGradient;
}
side
{
type slip;
}
"ahmed.*"
{
type kqRWallFunction;
value uniform 0.135;
}
stilts
{
type kqRWallFunction;
value uniform 0.135;
}
ground
{
type kqRWallFunction;
value uniform 0.135;
}
}
internalField uniform 0.135;
boundaryField
{
inlet
{
type fixedValue;
value uniform 0.135;
}
outlet
{
type zeroGradient;
}
side
{
type slip;
}
"ahmed.*"
{
type kqRWallFunction;
value uniform 0.135;
}
stilts
{
type kqRWallFunction;
value uniform 0.135;
}
ground
{
type kqRWallFunction;
value uniform 0.135;
}
}
epsilon:
dimensions [0 2 -3 0 0 0 0];
internalField uniform 0.018912309598231;
boundaryField
{
inlet
{
type fixedValue;
value uniform 0.018912309598231;
}
outlet
{
type zeroGradient;
}
"ahmed.*"
{
type epsilonWallFunction;
value uniform 0.018912309598231;
}
stilts
{
type epsilonWallFunction;
value uniform 0.018912309598231;
}
ground
{
type epsilonWallFunction;
value uniform 0.018912309598231;
}
side
{
type slip;
}
}
nut:
dimensions [0 2 -3 0 0 0 0];
internalField uniform 0.018912309598231;
boundaryField
{
inlet
{
type fixedValue;
value uniform 0.018912309598231;
}
outlet
{
type zeroGradient;
}
"ahmed.*"
{
type epsilonWallFunction;
value uniform 0.018912309598231;
}
stilts
{
type epsilonWallFunction;
value uniform 0.018912309598231;
}
ground
{
type epsilonWallFunction;
value uniform 0.018912309598231;
}
side
{
type slip;
}
}
nut:
dimensions [0 2 -1 0 0 0 0];
internalField uniform 0;
boundaryField
{
inlet
{
type calculated;
value uniform 0;
}
outlet
{
type calculated;
value uniform 0;
}
side
{
type calculated;
value uniform 0;
}
ground
{
type nutkWallFunction;
value uniform 0;
}
"ahmed.*"
{
type nutkWallFunction;
value uniform 0;
}
stilts
{
type nutkWallFunction;
value uniform 0;
}
}
internalField uniform 0;
boundaryField
{
inlet
{
type calculated;
value uniform 0;
}
outlet
{
type calculated;
value uniform 0;
}
side
{
type calculated;
value uniform 0;
}
ground
{
type nutkWallFunction;
value uniform 0;
}
"ahmed.*"
{
type nutkWallFunction;
value uniform 0;
}
stilts
{
type nutkWallFunction;
value uniform 0;
}
}
How does one get the values of k and epsilon and similarly for k and omega? Based on ANSYS' intensity and viscosity ratio model (of 1% and 10 respectively), my value of k for 40 m/s is 0.24 and epsilon is 34.something at the inlet. How do I implement this here? Similarly for k and omega,how do we calculate them. Please tell me, because online resources have been confusing me. And also, does boundary layer thickness influence the drag coefficient results? How do I calculate first layer thickness and final boundary length?
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