[qferon]

Hello everyone,

I'm trying to calculate natural convection in a small slot surrounded by a solid with temperature from 110 K and 173 K. I'm using chtMultiRegionFaom to solve it.

When I'm using constant properties for the fluid everything is doing good, but as soon as try to implement polynomial transport properties, my case run few iterations and then crash with the following message (see picture attached below).

I try to run the simulation with deltaT equals to 5e-04 but it still crash. I'm trying with delta T equals to 5e-08 but it takes a very long time. My checkMesh is OK. There is my fvScheme and fvSolution for the fluid attached below.

/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 5.x |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "system/fluid";
object fvSchemes;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

ddtSchemes
{
default Euler;
}

gradSchemes
{
default Gauss linear;
}

divSchemes
{
default none;

div(phi,U) Gauss linearUpwind grad(U);
div(phi,K) Gauss linearUpwind grad(U);
div(phi,h) Gauss linearUpwind grad(U);
div(phi,k) Gauss linearUpwind grad(U);
div(phi,epsilon) Gauss linearUpwind grad(U);
div(phi,omega) Gauss linearUpwind grad(U);
div(phi,R) Gauss linearUpwind grad(U);
div(R) Gauss linearUpwind grad(U);
div(((rho*nuEff)*dev2(T(grad(U))))) Gauss linear;
}

laplacianSchemes
{
default Gauss linear corrected;
}

interpolationSchemes
{
default linear;
}

snGradSchemes
{
default corrected;
}

wallDist
{
method meshWave;
}
// ************************************************** *********************** //


/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 5.x |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "system/fluid";
object fvSolution;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

solvers
{
rho
{
solver PCG;
preconditioner DIC;
tolerance 1e-6;
relTol 0.1;
}

rhoFinal
{
$rho;
tolerance 1e-5;
relTol 0;
}

p_rgh
{
solver PCG;
preconditioner DIC;
tolerance 1e-3;
relTol 0.01;
maxIter 2000;
}

p_rghFinal
{
$p_rgh;
tolerance 1e-3;
relTol 0;
}

"(U|h|k|epsilon|omega|R)"
{
solver PBiCGStab;
preconditioner DILU;
tolerance 1e-7;
relTol 0.1;
}

"(U|h|k|epsilon|omega|R)Final"
{
$U;
tolerance 1e-7;
relTol 0;
}
}

PIMPLE
{
momentumPredictor yes;
nCorrectors 10;
nOuterCorrectors 10;
nNonOrthogonalCorrectors 1;
}

relaxationFactors
{
equations
{
"h.*" 0.95;
"p_rgh.*" 0.7;
"rho.*" 0.7;
"U.*" 1;
"omega.*" 0.7;
"epsilon.*" 0.7;
}
}

// ************************************************** *********************** //



Thanks for everyone that can help !
Quentin

[Bloerb]

Your settings are no good. A final pressure residual of 1e-3 does not suffice for heat transfer. And you are using linearUpwind on every scheme which is no good for complex heat transfer simulations. In addition you are relaxing the final iteration even though this is an unsteady simulation.