[Andrea_85]

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:

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

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

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

[akidess]

Instead of vanLeer you can use MULES or SuperBee, both of which should be more compressive. Don't expect too much though.

[Andrea_85]

Thanks Anton, i'll give them a try.

best

andrea