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August 22, 2022, 10:13
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Need help to validate my simulation result
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#1 |
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New Member
Tintunoo
Join Date: Jul 2022
Posts: 1
Rep Power: 0  |
problem description -
-free fall rocket like object drop from 500 meters. -desired results are forces and moment coefficient for rigid body simulation. -free stream velocity 60 m/s. -angle of attack 5 deg. simulation setup - -box far field domain 10 times body length for 3D simulation. -inlet, top and bottom patches are velocity inlet type. -symmetry sides. -pressure outlet. -turbulent Model is kOmegaSST. -simpleFoam solver. Mesh -snappyHexMesh with 3 boundary layers of thickness 0.7 -total number of cell 1 Million. HTML Code:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: v2012 |
| \\ / A nd | Website: www.openfoam.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volVectorField;
object U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions [0 1 -1 0 0 0 0];
internalField uniform (59.771681 5.02293445 0);
boundaryField
{
airdrop
{
type noSlip;
}
inlet
{
type fixedValue;
value uniform (59.771681 5.02293445 0);
}
outlet
{
type zeroGradient;
}
sides
{
type symmetry;
}
}
// ************************************************************************* //
HTML Code:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: v2012 |
| \\ / A nd | Website: www.openfoam.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
location "1";
object p;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions [0 2 -2 0 0 0 0];
internalField uniform 0;
boundaryField
{
airdrop
{
type zeroGradient;
}
inlet
{
type zeroGradient;
}
outlet
{
type fixedValue;
value uniform 0;
}
sides
{
type symmetry;
}
}
// ************************************************************************* //
HTML Code:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: v2012 |
| \\ / A nd | Website: www.openfoam.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
location "1";
object omega;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions [0 0 -1 0 0 0 0];
internalField uniform 864200;
boundaryField
{
airdrop
{
type omegaWallFunction;
value uniform 1;
}
inlet
{
type turbulentMixingLengthDissipationRateInlet;
mixingLength 0.014;
value uniform 0.014;
}
outlet
{
type zeroGradient;
}
sides
{
type symmetry;
}
}
// ************************************************************************* //
HTML Code:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: v2012 |
| \\ / A nd | Website: www.openfoam.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
location "1";
object nut;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions [0 2 -1 0 0 0 0];
internalField uniform 0;
boundaryField
{
airdrop
{
type nutkWallFunction;
value uniform 0;
}
inlet
{
type calculated;
value uniform 0.01934;
}
outlet
{
type calculated;
value uniform 0;
}
sides
{
type symmetry;
}
}
// ************************************************************************* //
HTML Code:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: v2012 |
| \\ / A nd | Website: www.openfoam.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
location "1";
object k;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions [0 2 -2 0 0 0 0];
internalField uniform 0.1;
boundaryField
{
airdrop
{
type kqRWallFunction;
value uniform 1;
}
inlet
{
type turbulentIntensityKineticEnergyInlet;
intensity 0.01;
value uniform 0.01;
}
outlet
{
type zeroGradient;
}
sides
{
type symmetry;
}
}
// ************************************************************************* //
HTML Code:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: v2012 |
| \\ / A nd | Website: www.openfoam.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
object transportProperties;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
transportModel Newtonian;
nu 1.5e-05;
// ************************************************************************* //
HTML Code:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: v2012 |
| \\ / A nd | Website: www.openfoam.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "constant";
object turbulenceProperties;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
simulationType RAS;
RAS
{
RASModel kOmegaSST;
turbulence on;
printCoeffs on;
}
// ************************************************************************* //
HTML Code:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: v2012 |
| \\ / A nd | Website: www.openfoam.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "system";
object controlDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
application simpleFoam;
startFrom latestTime;
startTime 0;
stopAt endTime;
endTime 15000;
deltaT 1;
writeControl timeStep;
writeInterval 10;
purgeWrite 0;
writeFormat ascii;
writePrecision 6;
writeCompression off;
timeFormat general;
timePrecision 6;
runTimeModifiable true;
functions
{
forceCoeffs1
{
type forceCoeffs;
libs ("libforces.so");
writeControl writeTime;
writeFields true;
patches (fuckingbomb);
p p;
U U;
rho rhoInf; // Indicates incompressible
log true;
rhoInf 1; // Required when rho = rhoInf
liftDir (0 1 0);
dragDir (1 0 0);
CofR (0 0 0); // Axle midpoint on ground
pitchAxis (0 0 1);
magUInf 60;
lRef 2.41; // Wheelbase length
Aref 4.56; // Estimated
}
yPlus1
{
// Mandatory entries (unmodifiable)
type yPlus;
libs (fieldFunctionObjects);
// Optional (inherited) entries
writePrecision 8;
writeToFile true;
useUserTime true;
region region0;
enabled true;
log true;
timeStart 0;
timeEnd 1000;
executeControl timeStep;
executeInterval 1;
writeControl timeStep;
writeInterval 10;
}
}
// ************************************************************************* //
HTML Code:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: v2012 |
| \\ / A nd | Website: www.openfoam.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
object fvSchemes;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
ddtSchemes
{
default steadyState;
}
gradSchemes
{
default Gauss linear;
grad(p) Gauss linear;
grad(U) Gauss linear;
}
divSchemes
{
default none;
div(phi,U) bounded Gauss linearUpwind grad(U);
div(phi,k) bounded Gauss upwind;
div(phi,omega) bounded Gauss upwind;
div((nuEff*dev2(T(grad(U))))) Gauss linear;
}
laplacianSchemes
{
default Gauss linear corrected;
}
interpolationSchemes
{
default linear;
}
snGradSchemes
{
default corrected;
}
wallDist
{
method meshWave;
}
// ************************************************************************* //
HTML Code:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: v2012 |
| \\ / A nd | Website: www.openfoam.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
object fvSolution;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
solvers
{
p
{
solver GAMG;
tolerance 1e-7;
relTol 0.1;
smoother GaussSeidel;
}
Phi
{
$p;
}
U
{
solver smoothSolver;
smoother GaussSeidel;
tolerance 1e-8;
relTol 0.1;
nSweeps 1;
}
k
{
solver smoothSolver;
smoother GaussSeidel;
tolerance 1e-8;
relTol 0.1;
nSweeps 1;
}
omega
{
solver smoothSolver;
smoother GaussSeidel;
tolerance 1e-8;
relTol 0.1;
nSweeps 1;
}
}
SIMPLE
{
nNonOrthogonalCorrectors 3;
}
potentialFlow
{
nNonOrthogonalCorrectors 10;
}
relaxationFactors
{
fields
{
p 0.3;
}
equations
{
"(U|k|omega)" 0.7;
"(U|k|omega)Final" 1.0;
}
}
cache
{
grad(U);
}
// ************************************************************************* //
only Ux and omega resudual went below 1e-5. other residual doesn't goes below 1e-3. -yplus value are y+ : min = 81.6281, max = 13216.4, average = 1185.81 HTML Code:
Time = 639
smoothSolver: Solving for Ux, Initial residual = 9.52204e-05, Final residual = 6.89428e-06, No Iterations 3
smoothSolver: Solving for Uy, Initial residual = 0.000402492, Final residual = 2.90737e-05, No Iterations 3
smoothSolver: Solving for Uz, Initial residual = 0.00496712, Final residual = 0.000361654, No Iterations 3
GAMG: Solving for p, Initial residual = 0.00923487, Final residual = 0.000304668, No Iterations 2
GAMG: Solving for p, Initial residual = 0.0010415, Final residual = 5.96551e-05, No Iterations 2
GAMG: Solving for p, Initial residual = 0.000171178, Final residual = 1.68851e-05, No Iterations 2
GAMG: Solving for p, Initial residual = 4.20648e-05, Final residual = 2.52407e-06, No Iterations 3
time step continuity errors : sum local = 6.28704e-08, global = 1.01751e-09, cumulative = 0.00119196
smoothSolver: Solving for omega, Initial residual = 2.4579e-05, Final residual = 1.75449e-06, No Iterations 3
smoothSolver: Solving for k, Initial residual = 0.000100212, Final residual = 7.69947e-06, No Iterations 3
ExecutionTime = 3194.77 s ClockTime = 3379 s
forceCoeffs forceCoeffs1 execute:
Coefficients
Cd : 0.267388 (pressure: 0.251521 viscous: 0.0158662)
Cs : -0.0281329 (pressure: -0.0283496 viscous: 0.000216715)
Cl : 0.337512 (pressure: 0.336583 viscous: 0.000929208)
CmRoll : 0.206183 (pressure: 0.205689 viscous: 0.000494358)
CmPitch : 0.669585 (pressure: 0.657872 viscous: 0.011713)
CmYaw : -0.125541 (pressure: -0.116004 viscous: -0.00953733)
Cd(f) : 0.339877
Cd(r) : -0.0724894
Cs(f) : -0.139607
Cs(r) : 0.111475
Cl(f) : 0.838341
Cl(r) : -0.500829
-is my result acceptable and how can i improve to have convergance. Thank in advances. |
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| Tags |
| convergence issue, free fall analysis, incompressible fluid, simple algorithm |
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