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Pressure rising indefinitely with rhoSimpleFoam |
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April 16, 2015, 06:21 |
Pressure rising indefinitely with rhoSimpleFoam
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Join Date: Feb 2013
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Hello,
I'm trying to simulate the flow in a conical annular gap with a rotating inner wall for my masters thesis. I'm using rhoSimpleFoam. My Problem is, that I can't get a converged solution. Even after 100.000 Iterations the pressure continues to rise slowly. Here are my boundary conditions, fvSolution and fvSchemes: Code:
| ========= | | | \\ / F ield | OpenFOAM: The Open Source CFD Toolbox | | \\ / O peration | Version: 2.2.2 | | \\ / A nd | Web: www.OpenFOAM.org | | \\/ M anipulation | | \*---------------------------------------------------------------------------*/ FoamFile { version 2.0; format ascii; class volVectorField; object U; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // dimensions [0 1 -1 0 0 0 0]; internalField uniform (0 0 0); boundaryField { INLET { type flowRateInletVelocity; massFlowRate constant 0.0038; //0.004167 value uniform (0 0 0); } OUTLET { type pressureInletOutletVelocity; value uniform (0 0 0); } SYM_1_OBEN { type cyclicAMI; } SYM_1_UNTEN { type cyclicAMI; } SYM_2_OBEN { type cyclicAMI; } SYM_2_UNTEN { type cyclicAMI; } MOVINGWALL_OBEN { type rotatingWallVelocity; origin (0 0 0); axis (1 0 0); omega 838; } MOVINGWALL_UNTEN { type rotatingWallVelocity; origin (0 0 0); axis (1 0 0); omega 838; } BOHRUNG { type fixedValue; value uniform (0 0 0); } WALL_OBEN { type fixedValue; value uniform (0 0 0); } WALL_UNTEN { type fixedValue; value uniform (0 0 0); } PLENUMWALL { type fixedValue; value uniform (0 0 0); } KEIL { type slip; } GAP_S { type fixedValue; value uniform (0 0 0); } GAB_W { type fixedValue; value uniform (0 0 0); } } Code:
/*--------------------------------*- C++ -*----------------------------------*\ | ========= | | | \\ / F ield | OpenFOAM: The Open Source CFD Toolbox | | \\ / O peration | Version: 2.2.2 | | \\ / A nd | Web: www.OpenFOAM.org | | \\/ M anipulation | | \*---------------------------------------------------------------------------*/ FoamFile { version 2.0; format ascii; class volScalarField; object p; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // dimensions [1 -1 -2 0 0 0 0]; internalField uniform 320000; boundaryField { INLET { type zeroGradient; } OUTLET { type fixedValue; value uniform 220000; } SYM_1_OBEN { type cyclicAMI; } SYM_1_UNTEN { type cyclicAMI; } SYM_2_OBEN { type cyclicAMI; } SYM_2_UNTEN { type cyclicAMI; } MOVINGWALL_OBEN { type zeroGradient; } MOVINGWALL_UNTEN { type zeroGradient; } BOHRUNG { type zeroGradient; } WALL_OBEN { type zeroGradient; } WALL_UNTEN { type zeroGradient; } PLENUMWALL { type zeroGradient; } KEIL { type zeroGradient; } GAP_S { type zeroGradient; } GAB_W { type zeroGradient; } } Code:
/*--------------------------------*- C++ -*----------------------------------*\ | ========= | | | \\ / F ield | OpenFOAM: The Open Source CFD Toolbox | | \\ / O peration | Version: 2.2.2 | | \\ / A nd | Web: www.OpenFOAM.org | | \\/ M anipulation | | \*---------------------------------------------------------------------------*/ FoamFile { version 2.0; format ascii; class volScalarField; object T; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // dimensions [0 0 0 1 0 0 0]; internalField uniform 360; boundaryField { INLET { type fixedValue; value $internalField; } OUTLET { type inletOutlet; inletValue $internalField; value $internalField; } SYM_1_OBEN { type cyclicAMI; } SYM_1_UNTEN { type cyclicAMI; } SYM_2_OBEN { type cyclicAMI; } SYM_2_UNTEN { type cyclicAMI; } MOVINGWALL_OBEN { type zeroGradient; } MOVINGWALL_UNTEN { type zeroGradient; } BOHRUNG { type zeroGradient; } WALL_UNTEN { type fixedValue; value $internalField; } WALL_OBEN { type fixedValue; value $internalField; } PLENUMWALL { type zeroGradient; } KEIL { type zeroGradient; } GAP_S { type zeroGradient; } GAB_W { type zeroGradient; } } Code:
/*--------------------------------*- C++ -*----------------------------------*\ | ========= | | | \\ / F ield | OpenFOAM: The Open Source CFD Toolbox | | \\ / O peration | Version: 2.2.2 | | \\ / A nd | Web: www.OpenFOAM.org | | \\/ M anipulation | | \*---------------------------------------------------------------------------*/ FoamFile { version 2.0; format ascii; class dictionary; location "system"; object fvSolution; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // solvers { p { solver GAMG; tolerance 1e-7; //1e-8 relTol 0.05; smoother GaussSeidel; nPreSweeps 0; nPostSweeps 2; cacheAgglomeration on; agglomerator faceAreaPair; nCellsInCoarsestLevel 100; mergeLevels 1; } U { solver smoothSolver; smoother GaussSeidel; nSweeps 2; tolerance 1e-07; ////1e-08 relTol 0.01; } h { solver PBiCG; preconditioner DILU; tolerance 1e-7; //1e-09 relTol 0.1; } "(k|omega)" { $U; tolerance 1e-07; relTol 0.1; } } SIMPLE { nNonOrthogonalCorrectors 2; rhoMin rhoMin [ 1 -3 0 0 0 ] 1.5; rhoMax rhoMax [ 1 -3 0 0 0 ] 7; // transonic true; residualControl { p 1e-6; U 1e-6; h 1e-6; // possibly check turbulence fields "(k|epsilon|omega)" 1e-6; } } relaxationFactors { fields { p 0.3; //0.1 rho 0.005; //0.05 } equations { U 0.7; //0.7 k 0.7; //0.7 omega 0.7; //0.7 h 0.7; //0.7 } } Code:
/*--------------------------------*- C++ -*----------------------------------*\ | ========= | | | \\ / F ield | OpenFOAM: The Open Source CFD Toolbox | | \\ / O peration | Version: 2.2.2 | | \\ / A nd | Web: www.OpenFOAM.org | | \\/ M anipulation | | \*---------------------------------------------------------------------------*/ FoamFile { version 2.0; format ascii; class dictionary; location "system"; object fvSchemes; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // ddtSchemes { default steadyState; } gradSchemes { default Gauss linear;//cellLimited Gauss linear 1.0; // Gauss linear; } divSchemes { default bounded Gauss upwind; div(phi,U) bounded Gauss upwind;//bounded Gauss upwind; div((muEff*dev2(T(grad(U))))) Gauss linear; div(phi,e) bounded Gauss upwind; div(phi,k) bounded Gauss upwind; div(phi,omega) bounded Gauss upwind; div(phi,Ekp) bounded Gauss upwind; } laplacianSchemes { default Gauss linear corrected;//Gauss linear limited 0.5; //Gauss linear corrected; } interpolationSchemes { default linear; } snGradSchemes { default corrected; //limited 0.5; } fluxRequired { default no; p ; } // ************************************************************************* // I really hope, that someone can give me any hints, what I can do to stabilize my solution. Thank you in advance! If you need any additional information, feel free to ask edit: One problem that I've found is, that the enthalpy is converging very slowly. I've attached a gnuplot graph with my residuals. Could this be the cause of my problems? If so, what can I do about it? |
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