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January 29, 2013, 10:47 |
Lag while running DES with pimpleFoam
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#1 |
New Member
David Bergman
Join Date: Jun 2012
Posts: 4
Rep Power: 13 |
Hello fellow Foamers!
I was wondering if anyone has experienced a sort of "lag" upon reaching the nuTilda calculation step while doing a DDES simulation with pimpleFoam? Im running my case in parallel on 128 cpu's with approx 50k cells on each. All other variables seem to be calculated almost instantantly but when it reaches nuTilda it seems to freeze or lag for a second or two and then continue. And it only does one iteration on nuTilda, it shouldn't take so long right? This lag causes my simulation time to pretty much double which is really not good since it already is quite long. Anyone experienced this or something similar? Any known solutions on how to prevent this? I suspect there could be something wrong with my fvSolution or fvSchemes setup so I'm posting these below. Code:
/*--------------------------------*- C++ -*----------------------------------*\ | ========= | | | \\ / F ield | OpenFOAM: The Open Source CFD Toolbox | | \\ / O peration | Version: 2.0.1 | | \\ / A nd | Web: www.OpenFOAM.com | | \\/ M anipulation | | \*---------------------------------------------------------------------------*/ FoamFile { version 2.0; format ascii; class dictionary; location "system"; object fvSchemes; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // ddtSchemes { default CrankNicholson 0.5; } gradSchemes { default Gauss linear; grad(p) Gauss linear; grad(U) Gauss linear; } divSchemes // filteredLinear(2) is best according to Eugene de Villiers { default none; div(phi,U) Gauss limitedLinearV 1; div(phi,nuTilda) Gauss upwind; div((nuEff*dev(T(grad(U))))) Gauss linear; } laplacianSchemes { default none; laplacian(nuEff,U) Gauss linear corrected; //limited 0.5; laplacian((1|A(U)),p) Gauss linear corrected; // limited 0.5; laplacian(DnuTildaEff,nuTilda) Gauss linear corrected; // limited 0.5; laplacian(1,p) Gauss linear corrected; // limited 0.5; } interpolationSchemes { default linear; interpolate(U) linear; } snGradSchemes { default corrected; } fluxRequired { default no; p ; } // ************************************************************************* // Code:
/*--------------------------------*- C++ -*----------------------------------*\ | ========= | | | \\ / F ield | OpenFOAM: The Open Source CFD Toolbox | | \\ / O peration | Version: 2.0.1 | | \\ / A nd | Web: www.OpenFOAM.com | | \\/ M anipulation | | \*---------------------------------------------------------------------------*/ FoamFile { version 2.0; format ascii; class dictionary; location "system"; object fvSolution; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // solvers { p { solver GAMG; tolerance 1e-04; //relTol 0.01; smoother GaussSeidel; cacheAgglomeration true; nCellsInCoarsestLevel 10; agglomerator faceAreaPair; mergeLevels 1; // solver PCG; // preconditioner FDIC; // tolerance 1e-04; // //relTol 0.1; // maxIter 500; } pFinal { solver GAMG; tolerance 1e-05; //relTol 0.01; smoother GaussSeidel; cacheAgglomeration true; nCellsInCoarsestLevel 10; agglomerator faceAreaPair; mergeLevels 1; // solver PCG; // preconditioner FDIC; // tolerance 1e-05; // //relTol 0.1; // maxIter 500; } "(U|nuTilda)" { solver PBiCG; preconditioner DILU; tolerance 1e-06; //relTol 0.1; } "(U|nuTilda)Final" { solver PBiCG; preconditioner DILU; tolerance 1e-06; //relTol 0.1; } } // PISO // { // nCorrectors 2; // nNonOrthogonalCorrectors 0; // pRefCell 0; // pRefValue 0; // } PIMPLE { nOuterCorrectors 2; nCorrectors 2; nNonOrthogonalCorrectors 0; pRefCell 0; pRefValue 0; } relaxationFactors { "p.*" 0.3; "U.*" 0.5; "nuTilda.*" 0.5; } // ************************************************************************* // |
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