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-   -   kOmegaSST in openfoam 1.6 (http://www.cfd-online.com/Forums/openfoam/73239-komegasst-openfoam-1-6-a.html)

Gearb0x March 2, 2010 17:10

kOmegaSST in openfoam 1.6
 
Hello,

I'd like to know if the kOmegaSST in openfoam 1.6 is a low-re Models or not? because in fluent, if I understand well, it is.

Also, if that's the case, how to set it up?
Cause in the tutorials incompressible/simpleFoam/motorbike

in the "constant" directory of this case I have :
RASproperties
Code:

/*--------------------------------*- C++ -*----------------------------------*\
| =========                |                                                |
| \\      /  F ield        | OpenFOAM: The Open Source CFD Toolbox          |
|  \\    /  O peration    | Version:  1.6                                  |
|  \\  /    A nd          | Web:      http://www.OpenFOAM.org              |
|    \\/    M anipulation  |                                                |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version    2.0;
    format      ascii;
    class      dictionary;
    object      RASProperties;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

RASModel            kOmegaSST;

turbulence          on;

printCoeffs        on;


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

and
turbulenceproperties
Code:

/*--------------------------------*- C++ -*----------------------------------*\
| =========                |                                                |
| \\      /  F ield        | OpenFOAM: The Open Source CFD Toolbox          |
|  \\    /  O peration    | Version:  1.6                                  |
|  \\  /    A nd          | Web:      www.OpenFOAM.org                      |
|    \\/    M anipulation  |                                                |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version    2.0;
    format      ascii;
    class      dictionary;
    location    "constant";
    object      turbulenceProperties;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

turbulenceModel SpalartAllmaras;

turbulence      on;

laminarCoeffs
{
}

kEpsilonCoeffs
{
    Cmu            Cmu [ 0 0 0 0 0 0 0 ] 0.09;
    C1              C1 [ 0 0 0 0 0 0 0 ] 1.44;
    C2              C2 [ 0 0 0 0 0 0 0 ] 1.92;
    alphaEps        alphaEps [ 0 0 0 0 0 0 0 ] 0.76923;
}

RNGkEpsilonCoeffs
{
    Cmu            Cmu [ 0 0 0 0 0 0 0 ] 0.0845;
    C1              C1 [ 0 0 0 0 0 0 0 ] 1.42;
    C2              C2 [ 0 0 0 0 0 0 0 ] 1.68;
    alphak          alphaK [ 0 0 0 0 0 0 0 ] 1.39;
    alphaEps        alphaEps [ 0 0 0 0 0 0 0 ] 1.39;
    eta0            eta0 [ 0 0 0 0 0 0 0 ] 4.38;
    beta            beta [ 0 0 0 0 0 0 0 ] 0.012;
}

NonlinearKEShihCoeffs
{
    Cmu            Cmu [ 0 0 0 0 0 0 0 ] 0.09;
    C1              C1 [ 0 0 0 0 0 0 0 ] 1.44;
    C2              C2 [ 0 0 0 0 0 0 0 ] 1.92;
    alphak          alphak [ 0 0 0 0 0 0 0 ] 1;
    alphaEps        alphaEps [ 0 0 0 0 0 0 0 ] 0.76932;
    A1              A1 [ 0 0 0 0 0 0 0 ] 1.25;
    A2              A2 [ 0 0 0 0 0 0 0 ] 1000;
    Ctau1          Ctau1 [ 0 0 0 0 0 0 0 ] -4;
    Ctau2          Ctau2 [ 0 0 0 0 0 0 0 ] 13;
    Ctau3          Ctau3 [ 0 0 0 0 0 0 0 ] -2;
    alphaKsi        alphaKsi [ 0 0 0 0 0 0 0 ] 0.9;
}

LienCubicKECoeffs
{
    C1              C1 [ 0 0 0 0 0 0 0 ] 1.44;
    C2              C2 [ 0 0 0 0 0 0 0 ] 1.92;
    alphak          alphak [ 0 0 0 0 0 0 0 ] 1;
    alphaEps        alphaEps [ 0 0 0 0 0 0 0 ] 0.76923;
    A1              A1 [ 0 0 0 0 0 0 0 ] 1.25;
    A2              A2 [ 0 0 0 0 0 0 0 ] 1000;
    Ctau1          Ctau1 [ 0 0 0 0 0 0 0 ] -4;
    Ctau2          Ctau2 [ 0 0 0 0 0 0 0 ] 13;
    Ctau3          Ctau3 [ 0 0 0 0 0 0 0 ] -2;
    alphaKsi        alphaKsi [ 0 0 0 0 0 0 0 ] 0.9;
}

QZetaCoeffs
{
    Cmu            Cmu [ 0 0 0 0 0 0 0 ] 0.09;
    C1              C1 [ 0 0 0 0 0 0 0 ] 1.44;
    C2              C2 [ 0 0 0 0 0 0 0 ] 1.92;
    alphaZeta      alphaZeta [ 0 0 0 0 0 0 0 ] 0.76923;
    anisotropic    no;
}

LaunderSharmaKECoeffs
{
    Cmu            Cmu [ 0 0 0 0 0 0 0 ] 0.09;
    C1              C1 [ 0 0 0 0 0 0 0 ] 1.44;
    C2              C2 [ 0 0 0 0 0 0 0 ] 1.92;
    alphaEps        alphaEps [ 0 0 0 0 0 0 0 ] 0.76923;
}

LamBremhorstKECoeffs
{
    Cmu            Cmu [ 0 0 0 0 0 0 0 ] 0.09;
    C1              C1 [ 0 0 0 0 0 0 0 ] 1.44;
    C2              C2 [ 0 0 0 0 0 0 0 ] 1.92;
    alphaEps        alphaEps [ 0 0 0 0 0 0 0 ] 0.76923;
}

LienCubicKELowReCoeffs
{
    Cmu            Cmu [ 0 0 0 0 0 0 0 ] 0.09;
    C1              C1 [ 0 0 0 0 0 0 0 ] 1.44;
    C2              C2 [ 0 0 0 0 0 0 0 ] 1.92;
    alphak          alphak [ 0 0 0 0 0 0 0 ] 1;
    alphaEps        alphaEps [ 0 0 0 0 0 0 0 ] 0.76923;
    A1              A1 [ 0 0 0 0 0 0 0 ] 1.25;
    A2              A2 [ 0 0 0 0 0 0 0 ] 1000;
    Ctau1          Ctau1 [ 0 0 0 0 0 0 0 ] -4;
    Ctau2          Ctau2 [ 0 0 0 0 0 0 0 ] 13;
    Ctau3          Ctau3 [ 0 0 0 0 0 0 0 ] -2;
    alphaKsi        alphaKsi [ 0 0 0 0 0 0 0 ] 0.9;
    Am              Am [ 0 0 0 0 0 0 0 ] 0.016;
    Aepsilon        Aepsilon [ 0 0 0 0 0 0 0 ] 0.263;
    Amu            Amu [ 0 0 0 0 0 0 0 ] 0.00222;
}

LienLeschzinerLowReCoeffs
{
    Cmu            Cmu [ 0 0 0 0 0 0 0 ] 0.09;
    C1              C1 [ 0 0 0 0 0 0 0 ] 1.44;
    C2              C2 [ 0 0 0 0 0 0 0 ] 1.92;
    alphak          alphak [ 0 0 0 0 0 0 0 ] 1;
    alphaEps        alphaEps [ 0 0 0 0 0 0 0 ] 0.76923;
    Am              Am [ 0 0 0 0 0 0 0 ] 0.016;
    Aepsilon        Aepsilon [ 0 0 0 0 0 0 0 ] 0.263;
    Amu            Amu [ 0 0 0 0 0 0 0 ] 0.00222;
}

LRRCoeffs
{
    Cmu            Cmu [ 0 0 0 0 0 0 0 ] 0.09;
    Clrr1          Clrr1 [ 0 0 0 0 0 0 0 ] 1.8;
    Clrr2          Clrr2 [ 0 0 0 0 0 0 0 ] 0.6;
    C1              C1 [ 0 0 0 0 0 0 0 ] 1.44;
    C2              C2 [ 0 0 0 0 0 0 0 ] 1.92;
    Cs              Cs [ 0 0 0 0 0 0 0 ] 0.25;
    Ceps            Ceps [ 0 0 0 0 0 0 0 ] 0.15;
    alphaEps        alphaEps [ 0 0 0 0 0 0 0 ] 0.76923;
}

LaunderGibsonRSTMCoeffs
{
    Cmu            Cmu [ 0 0 0 0 0 0 0 ] 0.09;
    Clg1            Clg1 [ 0 0 0 0 0 0 0 ] 1.8;
    Clg2            Clg2 [ 0 0 0 0 0 0 0 ] 0.6;
    C1              C1 [ 0 0 0 0 0 0 0 ] 1.44;
    C2              C2 [ 0 0 0 0 0 0 0 ] 1.92;
    C1Ref          C1Ref [ 0 0 0 0 0 0 0 ] 0.5;
    C2Ref          C2Ref [ 0 0 0 0 0 0 0 ] 0.3;
    Cs              Cs [ 0 0 0 0 0 0 0 ] 0.25;
    Ceps            Ceps [ 0 0 0 0 0 0 0 ] 0.15;
    alphaEps        alphaEps [ 0 0 0 0 0 0 0 ] 0.76923;
    alphaR          alphaR [ 0 0 0 0 0 0 0 ] 1.22;
}

SpalartAllmarasCoeffs
{
    alphaNut        alphaNut [ 0 0 0 0 0 0 0 ] 1.5;
    Cb1            Cb1 [ 0 0 0 0 0 0 0 ] 0.1355;
    Cb2            Cb2 [ 0 0 0 0 0 0 0 ] 0.622;
    Cw2            Cw2 [ 0 0 0 0 0 0 0 ] 0.3;
    Cw3            Cw3 [ 0 0 0 0 0 0 0 ] 2;
    Cv1            Cv1 [ 0 0 0 0 0 0 0 ] 7.1;
    Cv2            Cv2 [ 0 0 0 0 0 0 0 ] 5;
}

wallFunctionCoeffs
{
    kappa          kappa [ 0 0 0 0 0 0 0 ] 0.4187;
    E              E [ 0 0 0 0 0 0 0 ] 9;
}


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

I don't understand why in RAS it's "kOmegaSST" and in turbulence "spalartAllmaras"
Shouldn't it be the same? Does the 2 files are needed?

Thanks for your help

SD@TUB March 3, 2010 05:25

Hello Gearb0x,

the kOmegaSST turbulence model works with wall functions solely. So it is a high-Re-model!
In my state of knowledge there exist a low-Re-model. You will find some discussions within this forum.
According to the tutorial "incompressible/simpleFoam/motorbike" i guess that RASproperties is dominant and the solver initialize the associated coeffs from the turbuenceProperties dict.

/Stefan

Gearb0x March 3, 2010 07:02

Thanks for your help

So the model is not useful in my case :)


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