[sina_mech]

Hi FOAMers! :-)

I'm trying to simulate a flow with 2 inlets and 2 outlets. I can't reach a better convergence! Please see the attached for the residuals.

fvSolution

solvers
{
    p
    {
        solver          GAMG;
        tolerance       1e-07; // was 1e-6
        relTol          0.05; // was 0.1
        smoother        GaussSeidel;
        nPreSweeps      0;
        nPostSweeps     2;
        cacheAgglomeration on;
        agglomerator    faceAreaPair;
        nCellsInCoarsestLevel 10;
        mergeLevels     1;
    }

    "(U|k|epsilon|R|nuTilda)"
 
 {
        solver          smoothSolver;
        smoother        symGaussSeidel;
        tolerance       1e-06; // was 1e-5
        relTol          0.1; // was 0.1
    }  

}

SIMPLE
{
    nNonOrthogonalCorrectors 0;  // was 0 !

   residualControl
    {
        p               1e-5;
        U               1e-5;
        "(k|epsilon|omega)" 1e-5;
    } 
}

relaxationFactors
{
    fields
    {
        p               0.3;
    }
    equations
    {
        U               0.5;
        k               0.7;
        epsilon         0.7;
        R               0.7;
        nuTilda         0.7;
    }
}

fvSchemes

ddtSchemes
{
    default         steadyState;
}

gradSchemes
{
    default         edgeCellsLeastSquares;
  }

divSchemes
{
    default         none;
    div(phi,U)      bounded Gauss QUICK;
div(phi,k)      bounded Gauss upwind;
    div(phi,epsilon) bounded Gauss upwind;
     div((nuEff*dev(T(grad(U))))) Gauss linear;
}

laplacianSchemes
{
    default         Gauss linear corrected;
}

interpolationSchemes
{
    default         linear;
}

snGradSchemes
{
    default         corrected;
}

fluxRequired
{
    default         no;
    p               ;
}

[jherb]

What are your boundary conditions?

[sina_mech]

Two velocity inlets (fixed velocity, zero gradient pressure) . Two averaged pressure outlets (0kpa and 10kpa, zero-gradient velocity). The walls are no-slip (zero velocity, zero gradient pressure).

[jherb]

Does the two different pressure outlets make physically sense? Meaning: Is the pressure drop between the two outlets so high?

[sina_mech]

Yes It has a physical meaning. and I could get converged solution with Fluent but I want to get the converged solution with OpenFOAM.

[Tushar@cfd]

Hmmm, I would rather check these conditions first. Try with these and check your convergence...

gradSchemes
{
default Gauss linear;
}

divSchemes
{
default none;
div(phi,U) Gauss upwind;
div(phi,k) Gauss upwind;
div(phi,epsilon) Gauss upwind;
div((nuEff*dev(T(grad(U))))) Gauss linear;
}

-
Best Luck!