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Numerical instabilities due to temperature at inlet |
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June 18, 2013, 08:31 |
Numerical instabilities due to temperature at inlet
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Join Date: Apr 2013
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Hi Foamers,
I have a problem with my simulation case. I want to simulate a flow through a cube with 1.5 m/s. The temperature of the cube is 1373 K, the inflow should have 1573 K. I use buoyantSimpleFoam and kEpsilon. If I set the inlet-temp. to 1373 K everything works fine. If i set the inlet.-temp. to 1573 K numerical instabilities at the inlet occure. The temperature in some areas rises quite high, respectively drops. I have no idea why, I guess something in my BCs is wrong. The BCs are: Code:
/*--------------------------------*- C++ -*----------------------------------*\ | ========= | | | \\ / F ield | OpenFOAM: The Open Source CFD Toolbox | | \\ / O peration | Version: 2.2.0 | | \\ / A nd | Web: www.OpenFOAM.org | | \\/ M anipulation | | \*---------------------------------------------------------------------------*/ FoamFile { version 2.0; format ascii; class volScalarField; location "0"; object epsilon; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // dimensions [0 2 -3 0 0 0 0]; internalField uniform 1.505e-4; boundaryField { baseleft { type compressible::epsilonWallFunction; value uniform 1.505e-4; } baseright { type compressible::epsilonWallFunction; value uniform 1.505e-4; } sides { type compressible::epsilonWallFunction; value uniform 1.505e-4; } back { type fixedValue; value uniform 1.505e-4; } outlet { type zeroGradient; } } Code:
/*--------------------------------*- C++ -*----------------------------------*\ | ========= | | | \\ / F ield | OpenFOAM: The Open Source CFD Toolbox | | \\ / O peration | Version: 2.1.1 | | \\ / A nd | Web: www.OpenFOAM.org | | \\/ M anipulation | | \*---------------------------------------------------------------------------*/ FoamFile { version 2.0; format ascii; class volScalarField; location "0"; object k; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //dimensions [0 2 -2 0 0 0 0]; internalField uniform 2.383e-3; boundaryField { baseleft { type compressible::kqRWallFunction; value uniform 2.383e-3; } baseright { type compressible::kqRWallFunction; value uniform 2.383e-3; } sides { type compressible::kqRWallFunction; value uniform 2.383e-3; } back { type fixedValue; value uniform 2.383e-3; } outlet { type zeroGradient; } } Code:
/*--------------------------------*- C++ -*----------------------------------*\ | ========= | | | \\ / F ield | OpenFOAM: The Open Source CFD Toolbox | | \\ / O peration | Version: 2.1.1 | | \\ / A nd | Web: www.OpenFOAM.org | | \\/ M anipulation | | \*---------------------------------------------------------------------------*/ FoamFile { version 2.0; format ascii; class volScalarField; location "0"; object p; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //dimensions [ 1 -1 -2 0 0 0 0 ]; internalField uniform 101325; boundaryField { baseleft { type zeroGradient; } baseright { type zeroGradient; } sides { type zeroGradient; } back { type zeroGradient; } outlet { type fixedValue; value uniform 101325; } } Code:
/*--------------------------------*- C++ -*----------------------------------*\ | ========= | | | \\ / F ield | OpenFOAM: The Open Source CFD Toolbox | | \\ / O peration | Version: 2.1.1 | | \\ / A nd | Web: www.OpenFOAM.org | | \\/ M anipulation | | \*---------------------------------------------------------------------------*/ FoamFile { version 2.0; format ascii; class volScalarField; location "0"; object p_rgh; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //dimensions [ 1 -1 -2 0 0 0 0 ]; internalField uniform 101325; boundaryField { baseleft { type zeroGradient; } baseright { type zeroGradient; } sides { type zeroGradient; } back { type zeroGradient; } outlet { type fixedValue; value uniform 101325; } } Code:
/*--------------------------------*- C++ -*----------------------------------*\ | ========= | | | \\ / F ield | OpenFOAM: The Open Source CFD Toolbox | | \\ / O peration | Version: 2.1.1 | | \\ / A nd | Web: www.OpenFOAM.org | | \\/ M anipulation | | \*---------------------------------------------------------------------------*/ FoamFile { version 2.0; format ascii; class volScalarField; location "0"; object T; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //dimensions [0 0 0 1 0 0 0]; internalField uniform 1373; boundaryField { ".*" { type fixedValue; value uniform 1373; } back { type fixedValue; value uniform 1373; } outlet { type zeroGradient; } } Code:
/*--------------------------------*- C++ -*----------------------------------*\ | ========= | | | \\ / F ield | OpenFOAM: The Open Source CFD Toolbox | | \\ / O peration | Version: 2.1.1 | | \\ / A nd | Web: www.OpenFOAM.org | | \\/ M anipulation | | \*---------------------------------------------------------------------------*/ FoamFile { version 2.0; format ascii; class volVectorField; location "0"; object U; } // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //dimensions [0 1 -1 0 0 0 0]; internalField uniform (0 0 0); boundaryField { ".*" { type fixedValue; value uniform (0 0 0); } back { type fixedValue; value uniform (0 0 -1.5); } outlet { type zeroGradient; } } Many thanks in advance, regards |
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