alphaPredictor.C

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#include "incompressibleMultiphaseVoF.H"
#include "subCycle.H"
#include "MULES.H"
#include "fvcFlux.H"
 
// * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * * //
 
void Foam::solvers::incompressibleMultiphaseVoF::alphaSolve()
{
    const word alphaScheme("div(phi,alpha)");
    const word alpharScheme("div(phirb,alpha)");
 
    surfaceScalarField phic(mag(phi/mesh.magSf()));
    phic = min(cAlpha*phic, max(phic));
 
    UPtrList<const volScalarField> alphas(phases.size());
    PtrList<surfaceScalarField> alphaPhis(phases.size());
 
    forAll(phases, phasei)
    {
        const incompressibleVoFphase& alpha = phases[phasei];
 
        alphas.set(phasei, &alpha);
 
        alphaPhis.set
        (
            phasei,
            new surfaceScalarField
            (
                "phi" + alpha.name() + "Corr",
                fvc::flux
                (
                    phi,
                    alpha,
                    alphaScheme
                )
            )
        );
 
        surfaceScalarField& alphaPhi = alphaPhis[phasei];
 
        forAll(phases, phasej)
        {
            incompressibleVoFphase& alpha2 = phases[phasej];
 
            if (&alpha2 == &alpha) continue;
 
            surfaceScalarField phir(phic*mixture.nHatf(alpha, alpha2));
 
            alphaPhi += fvc::flux
            (
                -fvc::flux(-phir, alpha2, alpharScheme),
                alpha,
                alpharScheme
            );
        }
 
        // Limit alphaPhi for each phase
        MULES::limit
        (
            MULEScontrols,
            1.0/mesh.time().deltaT().value(),
            geometricOneField(),
            alpha,
            phi,
            alphaPhi,
            zeroField(),
            zeroField(),
            oneField(),
            zeroField(),
            false
        );
    }
 
    MULES::limitSum(alphas, alphaPhis, phi);
 
    rhoPhi = Zero;
 
    volScalarField sumAlpha
    (
        IOobject
        (
            "sumAlpha",
            mesh.time().name(),
            mesh
        ),
        mesh,
        dimensionedScalar(dimless, 0)
    );
 
    forAll(phases, phasei)
    {
        incompressibleVoFphase& alpha = phases[phasei];
        surfaceScalarField& alphaPhi = alphaPhis[phasei];
 
        MULES::explicitSolve
        (
            geometricOneField(),
            alpha,
            alphaPhi
        );
 
        rhoPhi += alphaPhi*alpha.rho();
 
        Info<< alpha.name() << " volume fraction, min, max = "
            << alpha.weightedAverage(mesh.V()).value()
            << ' ' << min(alpha).value()
            << ' ' << max(alpha).value()
            << endl;
 
        sumAlpha += alpha;
    }
 
    Info<< "Phase-sum volume fraction, min, max = "
        << sumAlpha.weightedAverage(mesh.V()).value()
        << ' ' << min(sumAlpha).value()
        << ' ' << max(sumAlpha).value()
        << endl;
 
    // Correct the sum of the phase-fractions to avoid 'drift'
    volScalarField sumCorr(1.0 - sumAlpha);
    forAll(phases, phasei)
    {
        incompressibleVoFphase& alpha = phases[phasei];
        alpha += alpha*sumCorr;
    }
}
 
 
void Foam::solvers::incompressibleMultiphaseVoF::alphaPredictor()
{
    const label nAlphaSubCycles = ceil(nAlphaSubCyclesPtr->value(alphaCoNum));
 
    if (nAlphaSubCycles > 1)
    {
        surfaceScalarField rhoPhiSum
        (
            IOobject
            (
                "rhoPhiSum",
                runTime.name(),
                mesh
            ),
            mesh,
            dimensionedScalar(rhoPhi.dimensions(), 0)
        );
 
        const dimensionedScalar totalDeltaT = runTime.deltaT();
 
        UPtrList<volScalarField> alphas(phases.size());
        forAll(phases, phasei)
        {
            alphas.set(phasei, &phases[phasei]);
        }
 
        for
        (
            subCycle<volScalarField, subCycleFields> alphaSubCycle
            (
                alphas,
                nAlphaSubCycles
            );
            !(++alphaSubCycle).end();
        )
        {
            alphaSolve();
            rhoPhiSum += (runTime.deltaT()/totalDeltaT)*rhoPhi;
        }
 
        rhoPhi = rhoPhiSum;
    }
    else
    {
        alphaSolve();
    }
 
    mixture.correct();
}
 
 
// ************************************************************************* //