CFD Online Discussion Forums - High diffusion in interFoam

Hi all,

i am simulating a meniscus that moves in capillary tubes of different shape with small contact angle (from 1° up to 30°). I have observed a very large diffusion of the interface which sometimes leads to non-physical or not-expected results. I was wondering if i can limit diffusion without without touching cAlpha, which is set to 1 at the moment, maybe playing with schemes for convective terms. Which schemes can be used in interFoam to limit diffusion?

This is how my fvScheme looks like:

Code:

ddtSchemes

{

    default         Euler;

}



gradSchemes

{

    default         leastSquares;

//    grad(U)         Gauss linear;

//    grad(alpha1)    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;

}

and fvSolution

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

    {

        solver          PCG;

        preconditioner  DIC;

        tolerance       1e-07;

        relTol          0;

    }



    U

    {

        solver          PBiCG;

        preconditioner  DILU;

        tolerance       1e-06;

        relTol          0;

    }

     UFinal

    {

        solver          PBiCG;

        preconditioner  DILU;

        tolerance       1e-06;

        relTol          0;

    }





PIMPLE

{

    momentumPredictor yes;

    nCorrectors     3;

    nNonOrthogonalCorrectors 1;

    nAlphaCorr      1;

    nAlphaSubCycles 3;

    cAlpha          1;

}

and controlDict

Code:

application     interFoam;



startFrom       startTime;



startTime       0;



stopAt          endTime;



endTime         0.22;



deltaT          0.000000001;



writeControl    adjustableRunTime;



writeInterval   0.01;



purgeWrite      0;



writeFormat     ascii;



writePrecision  6;



writeCompression uncompressed;



timeFormat      general;



timePrecision   6;



runTimeModifiable yes;



adjustTimeStep  yes;



maxCo           0.1;

maxAlphaCo      0.1;



maxDeltaT       0.01;

thanks

andrea