openfoam/applications/solvers/multiphase/interFoam/alphaEqn.H

{
    word alphaScheme("div(phi,alpha)");
    word alpharScheme("div(phirb,alpha)");

    surfaceScalarField phic(mag(phi/mesh.magSf()));
    phic = min(interface.cAlpha()*phic, max(phic));
    surfaceScalarField phir(phic*interface.nHatf());

    for (int aCorr=0; aCorr<nAlphaCorr; aCorr++)
    {
        surfaceScalarField phiAlpha
        (
            fvc::flux
            (
                phi,
                alpha1,
                alphaScheme
            )
          + fvc::flux
            (
                -fvc::flux(-phir, alpha2, alpharScheme),
                alpha1,
                alpharScheme
            )
        );

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

        alpha2 = 1.0 - alpha1;
        rhoPhi = phiAlpha*(rho1 - rho2) + phi*rho2;
    }

    Info<< "Phase-1 volume fraction = "
        << alpha1.weightedAverage(mesh.Vsc()).value()
        << "  Min(alpha1) = " << min(alpha1).value()
        << "  Max(alpha1) = " << max(alpha1).value()
        << endl;
}