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-   -   Discretisation schemes and solution (keyword) ??? (http://www.cfd-online.com/Forums/openfoam/89251-discretisation-schemes-solution-keyword.html)

phuchuynh June 8, 2011 06:50

Discretisation schemes and solution (keyword) ???
 
Hi !
I am new to using OpenFoam 1.7.1. I want to learn how to use it better. To start , I am considering GUI's for OpenFoam. However, I am having some trouble. For example :
1 / Key word of Schemse : " default Euler , Gauss linear, Gauss limitedLinearV, Gauss vanLeer,......"
Code:

 
ddtSchemes
{
    default        Euler;
}

gradSchemes
{
    default        Gauss linear;
}

divSchemes
{
    div(rho*phi,U)  Gauss limitedLinearV 1;
    div(phi,alpha)  Gauss vanLeer;
    div(phirb,alpha) Gauss interfaceCompression;
}

laplacianSchemes
{
    default        Gauss linear corrected;
}

interpolationSchemes
{
    default        linear;
}

snGradSchemes
{
    default        corrected;
}

fluxRequired
{
    default        no;
    p_rgh;
    pcorr;
    alpha1;
}

2/ Key word of Solution : " PCG , DIC, PBiCG,......"
Code:

solvers
{
    pcorr
    {
        solver          PCG;
        preconditioner  DIC;
        tolerance      1e-10;
        relTol          0;
    }

    p_rgh
    {
        solver          PCG;
        preconditioner  DIC;
        tolerance      1e-07;
        relTol          0.05;
    }

    p_rghFinal
    {
        $p_rgh;
        tolerance      1e-07;
        relTol          0;
    }

    U
    {
        solver          PBiCG;
        preconditioner  DILU;
        tolerance      1e-06;
        relTol          0;
    }
}

PISO
{
    momentumPredictor no;
    nCorrectors    3;
    nNonOrthogonalCorrectors 0;
    nAlphaCorr      1;
    nAlphaSubCycles 2;
    cAlpha          1;
}

I don't know how to use it. what does keyword mean ? How do I use them?
3/ Where are governing equations ? and how can I repair them to creat new solver ?
Plz help me ! can suggest other GUI's. Thank you

Best regards ! :)


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