| hxaxtma |
April 5, 2016 04:14 |
rhoSimpleFoam crashes for Ma=0.6
Hi guys,
I am struggeling with following problem. I set up a case with kOmegaSST and rhoSimpleFoam for calculating external flow at Ma=0.6 and rhoSimpleFoam crashes immediatly after Iteration 2. For lower Ma number the solver runs. I do not find any problem in my setup. Maybe you can help me here
1) My Mesh is fine, checkMesh gives only a few nonOrthoCells and skewCells are found.
Code:
Checking geometry...
Overall domain bounding box (-2.5 -1.9997 -1.99995) (4.5 1.99943 1.99999)
Mesh has 3 geometric (non-empty/wedge) directions (1 1 1)
Mesh has 3 solution (non-empty) directions (1 1 1)
Boundary openness (1.13991e-16 3.30607e-16 6.08633e-16) OK.
Max cell openness = 1.26282e-15 OK.
Max aspect ratio = 41.6873 OK.
Minimum face area = 2.56578e-11. Maximum face area = 0.0112171. Face area magnitudes OK.
Min volume = 8.23851e-15. Max volume = 0.0010981. Total volume = 87.8213. Cell volumes OK.
Mesh non-orthogonality Max: 89.4792 average: 10.4901
*Number of severely non-orthogonal (> 70 degrees) faces: 272.
Non-orthogonality check OK.
<<Writing 272 non-orthogonal faces to set nonOrthoFaces
Face pyramids OK.
***Max skewness = 6.92056, 30 highly skew faces detected which may impair the quality of the results
<<Writing 30 skew faces to set skewFaces
Coupled point location match (average 0) OK.
Failed 1 mesh checks.
End
2) My BCs are the following
Code:
Valid fields:
volScalarField nut
volVectorField U
volScalarField k
volScalarField alphat
volScalarField p
volScalarField T
volScalarField omega
volScalarField epsilon
wall : geom_3
wall : geom_2
wall : geom_1
scalar nut generic
scalar k generic
scalar alphat generic
scalar p zeroGradient
scalar T zeroGradient
scalar omega generic
scalar epsilon generic
vector U fixedValue
patch : in
scalar nut calculated
scalar k turbulentIntensityKineticEnergyInlet
scalar alphat calculated
scalar p zeroGradient
scalar T fixedValue
scalar omega fixedValue
scalar epsilon generic
vector U fixedValue
wall : geom_3
scalar nut generic
scalar k generic
scalar alphat generic
scalar p zeroGradient
scalar T zeroGradient
scalar omega generic
scalar epsilon generic
vector U fixedValue
patch : out
scalar nut calculated
scalar k zeroGradient
scalar alphat calculated
scalar p fixedValue
scalar T zeroGradient
scalar omega zeroGradient
scalar epsilon zeroGradient
vector U zeroGradient
wall : side
scalar nut calculated
scalar k slip -> Is lip condition for k, epsilon and omega OK here?
scalar alphat calculated
scalar p slip
scalar T slip
scalar omega slip
scalar epsilon slip
vector U slip
3)Initializing Turbulence Parameters by CFD-Online Tool at u_0=200m/s, nut/nu=10 and intensity of 0.5% results in
Code:
k= 1.5
epsilon = 1350
omega = 10000 -> Is This value OK?
4) I started to underrelax the pressure field and the simulation runs further, but crashes just on later iterations. Here are my fvSchemes
Code:
ddtSchemes
{
default steadyState;
}
gradSchemes
{
default cellLimited Gauss linear 1;
}
divSchemes
{
default bounded Gauss upwind;
div(phi,U) bounded Gauss upwind;
div(phi,e) bounded Gauss upwind;
div(phi,epsilon) bounded Gauss upwind;
div(phi,omega) bounded Gauss upwind;
div(phi,k) bounded Gauss upwind;
div(phi,Ekp) bounded Gauss upwind;
div(((rho*nuEff)*dev2(T(grad(U))))) Gauss linear;
}
laplacianSchemes
{
default Gauss linear orthogonal;
}
interpolationSchemes
{
default linear;
}
snGradSchemes
{
default orthogonal;//corrected;
}
wallDist
{
method meshWave;
}
5) and my fvSolution
Code:
p
{
solver GAMG;
tolerance 1e-08;
relTol 0.05;
smoother GaussSeidel;
cacheAgglomeration on;
nCellsInCoarsestLevel 20;
agglomerator faceAreaPair;
mergeLevels 1;
}
U
{
solver smoothSolver;
smoother GaussSeidel;
nSweeps 2;
tolerance 1e-08;
relTol 0.1;
}
e
{
solver smoothSolver;
smoother symGaussSeidel;
tolerance 1e-08;
relTol 0.1;
}
"(k|epsilon|omega)"
{
$U;
tolerance 1e-07;
relTol 0.1;
}
Phi
{
solver GAMG;
smoother DIC;
cacheAgglomeration on;
agglomerator faceAreaPair;
nCellsInCoarsestLevel 10;
mergeLevels 1;
tolerance 1e-06;
relTol 0.01;
}
}
potentialFlow
{
nNonOrthogonalCorrectors 10;
}
SIMPLE
{
nNonOrthogonalCorrectors 10;
nCorrectors 2;
rhoMin 0.5;
rhoMax 2.5;
pRefCell 0;
pRefValue 0;
residualControl
{
p 1e-2;
U 1e-4;
e 1e-3;
// possibly check turbulence fields
"(k|epsilon|omega)" 1e-3;
}
}
relaxationFactors
{
fields
{
p 0.01; //was 0.3
rho 0.01;
}
equations
{
U 0.7;
"(k|epsilon|omega)" 0.7;
e 0.5;
}
}
and this is the error, it always happens at Solving for p:
Code:
smoothSolver: Solving for Ux, Initial residual = 0.515113, Final residual = 0.0248749, No Iterations 6
smoothSolver: Solving for Uy, Initial residual = 0.572182, Final residual = 0.0216566, No Iterations 6
smoothSolver: Solving for Uz, Initial residual = 0.572538, Final residual = 0.0219375, No Iterations 6
smoothSolver: Solving for e, Initial residual = 0.950916, Final residual = 0.0732206, No Iterations 1
#0 Foam::error::printStack(Foam::Ostream&) at ??:?
#1 Foam::sigFpe::sigHandler(int) at ??:?
#2 ? in "/lib/x86_64-linux-gnu/libc.so.6"
#3 Foam::hePsiThermo<Foam::psiThermo, Foam::pureMixture<Foam::sutherlandTransport<Foam::species::thermo<Foam::hConstThermo<Foam::perfectGas<Foam::specie> >, Foam::sensibleInternalEnergy> > > >::calculate() at ??:?
#4 Foam::hePsiThermo<Foam::psiThermo, Foam::pureMixture<Foam::sutherlandTransport<Foam::species::thermo<Foam::hConstThermo<Foam::perfectGas<Foam::specie> >, Foam::sensibleInternalEnergy> > > >::correct() at ??:?
#5 ? at ??:?
#6 __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
#7 ? at ??:?
Floating point exception
I am struggeling with this case for two weeks now and do not know what I am setting up wrong. Maybe you have an idea.
And last question, If my boundary layer resolution is y+<1, are the upper known BCs still valid?
Thanks in advance |
