| laurensvd |
February 20, 2012 10:15 |
rhoCentralFoam boundary issues with custom local time stepping
I have an axisymmetric problem which I am simulating with rhoCentralFoam and a k-Omega-SST turbulence model. At my outlet I have anomalies (see an example of the pressure distribution in the image below).
The reason for these anomalies is related to me using a local time stepping method which I got from this forum ( http://www.cfd-online.com/Forums/ope...ntralfoam.html). I dont have the anomalies in the original code without the local time stepping. Now, I would still like to have the local time stepping since I am only interested in the steady state solution and my calculations take way too long otherwise. Can anyone suggest some changes to get rid of these numerical errors?
My patches are defined as follows (not mentioning my model patches):
Code:
patch: frontAndBack
all wedge
patch: symmetryLine
all zeroGradient
patch: outlet
scalar k inletOutlet
scalar alphat calculated
scalar p fixedValue
scalar T fixedValue
scalar mut calculated
scalar omega inletOutlet
vector U zeroGradient
patch: atmosphere
scalar k fixedValue
scalar alphat calculated
scalar p slip
scalar T zeroGradient
scalar mut calculated
scalar omega fixedValue
vector U slip
patch: inlet
scalar k fixedValue
scalar alphat calculated
scalar p zeroGradient
scalar T zeroGradient
scalar mut calculated
scalar omega fixedValue
vector U fixedValue
My fvSolution is:
Code:
solvers
{
"(rho|rhoU|rhoE)"
{
solver diagonal;
}
U
{
solver smoothSolver;
smoother GaussSeidel;
nSweeps 2;
tolerance 1e-12;
relTol 0;
}
"(e|omega|k|R|epsilon|h)"
{
$U;
tolerance 1e-10;
relTol 0;
}
p
{
solver GAMG;
tolerance 1e-08;
relTol 0.01;
smoother GaussSeidel;
cacheAgglomeration off;
nCellsInCoarsestLevel 20;
agglomerator faceAreaPair;
mergeLevels 1;
}
}
and my fvSchemes:
Code:
fluxScheme Tadmor;
ddtSchemes
{
default localEuler rDeltaT;
}
gradSchemes
{
default cellLimited leastSquares 1;
}
divSchemes
{
default none;
div(tauMC) Gauss linear;
div(phi,k) Gauss Gamma 1;
div(phi,omega) Gauss Gamma 1;
}
laplacianSchemes
{
default Gauss linear corrected;
}
interpolationSchemes
{
default linear;
reconstruct(rho) Gamma 1;
reconstruct(U) GammaV 1;
reconstruct(T) Gamma 1;
}
snGradSchemes
{
default corrected;
}
fluxRequired
{
default no;
p;
}
http://i40.tinypic.com/w8xbww.png |
