CFD Online Discussion Forums - How to solve this alpha Eqn using MULES?

Hi Foamers,

I want to modify the interFoam solver where the alpha Eqn is like:

Eqn 1:
http://24.media.tumblr.com/6c11fdf1e...saho2_1280.png

The fluid Cell contains fluid phase 1 and phase 2, along with the solid phase, here \epsilon_f stands for the volume fraction occupied by fluid (V_phase1 + V_phase2).

\epsilon_f filed is also defined in createFields.H

Code:

    volScalarField voidfractionFluid

    (

        IOobject

        (

            "voidfractionFluid",

            runTime.timeName(),

            mesh,

            IOobject::MUST_READ,

            IOobject::AUTO_WRITE

        ),

        mesh

    );

The original VOF method in interFoam is:

Eqn 2:
http://25.media.tumblr.com/a69766b4c...saho1_1280.png
the implementation code of alpha equation:

Code:



 for (int aCorr=0; aCorr<nAlphaCorr; aCorr++)

    {

        surfaceScalarField phiAlpha

        (

            fvc::flux

            (

                phi,

                alpha1,

                alphaScheme

            )

          + fvc::flux

            (

                -fvc::flux(-phir, scalar(1) - alpha1, alpharScheme),

                alpha1,

                alpharScheme

            )

        );



        MULES::explicitSolve(alpha1, phi, phiAlpha, 1, 0);



        rhoPhi = phiAlpha*(rho1 - rho2) + phi*rho2;

So I wonder how to add the volScalarField voidfractionFluid to the MULES solver similar like above? Any hints will be highly appreciated!

Cheers,

David Long