SchaefferFrictionalStress.C

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    Copyright (C) 2011-2018 OpenFOAM Foundation
    Copyright (C) 2019 OpenCFD Ltd.
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License
    This file is part of OpenFOAM.

    OpenFOAM is free software: you can redistribute it and/or modify it
    under the terms of the GNU General Public License as published by
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#include "SchaefferFrictionalStress.H"
#include "addToRunTimeSelectionTable.H"
#include "unitConversion.H"

// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //

namespace Foam
{
namespace kineticTheoryModels
{
namespace frictionalStressModels
{
    defineTypeNameAndDebug(Schaeffer, 0);

    addToRunTimeSelectionTable
    (
        frictionalStressModel,
        Schaeffer,
        dictionary
    );
}
}
}


// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //

Foam::kineticTheoryModels::frictionalStressModels::Schaeffer::Schaeffer
(
    const dictionary& dict
)
:
    frictionalStressModel(dict),
    coeffDict_(dict.optionalSubDict(typeName + "Coeffs")),
    phi_("phi", dimless, coeffDict_)
{
    phi_ *= degToRad();
}


// * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //

Foam::kineticTheoryModels::frictionalStressModels::Schaeffer::~Schaeffer()
{}


// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //

Foam::tmp<Foam::volScalarField>
Foam::kineticTheoryModels::frictionalStressModels::Schaeffer::
frictionalPressure
(
    const phaseModel& phase,
    const dimensionedScalar& alphaMinFriction,
    const dimensionedScalar& alphaMax
) const
{
    const volScalarField& alpha = phase;

    return
        dimensionedScalar("", dimensionSet(1, -1, -2, 0, 0), 1e24)
       *pow(Foam::max(alpha - alphaMinFriction, scalar(0)), 10.0);
}


Foam::tmp<Foam::volScalarField>
Foam::kineticTheoryModels::frictionalStressModels::Schaeffer::
frictionalPressurePrime
(
    const phaseModel& phase,
    const dimensionedScalar& alphaMinFriction,
    const dimensionedScalar& alphaMax
) const
{
    const volScalarField& alpha = phase;

    return
        dimensionedScalar("", dimensionSet(1, -1, -2, 0, 0), 1e25)
       *pow(Foam::max(alpha - alphaMinFriction, scalar(0)), 9.0);
}


Foam::tmp<Foam::volScalarField>
Foam::kineticTheoryModels::frictionalStressModels::Schaeffer::nu
(
    const phaseModel& phase,
    const dimensionedScalar& alphaMinFriction,
    const dimensionedScalar& alphaMax,
    const volScalarField& pf,
    const volSymmTensorField& D
) const
{
    const volScalarField& alpha = phase;

    tmp<volScalarField> tnu
    (
        new volScalarField
        (
            IOobject
            (
                "Schaeffer:nu",
                phase.mesh().time().timeName(),
                phase.mesh(),
                IOobject::NO_READ,
                IOobject::NO_WRITE,
                IOobject::NO_REGISTER
            ),
            phase.mesh(),
            dimensionedScalar(dimensionSet(0, 2, -1, 0, 0), Zero)
        )
    );

    volScalarField& nuf = tnu.ref();

    forAll(D, celli)
    {
        if (alpha[celli] > alphaMinFriction.value())
        {
            nuf[celli] =
                0.5*pf[celli]*sin(phi_.value())
               /(
                    sqrt((1.0/3.0)*sqr(tr(D[celli])) - invariantII(D[celli]))
                  + SMALL
                );
        }
    }

    const fvPatchList& patches = phase.mesh().boundary();
    const volVectorField& U = phase.U();

    volScalarField::Boundary& nufBf = nuf.boundaryFieldRef();

    forAll(patches, patchi)
    {
        if (!patches[patchi].coupled())
        {
            nufBf[patchi] =
                (
                    pf.boundaryField()[patchi]*sin(phi_.value())
                   /(
                        mag(U.boundaryField()[patchi].snGrad())
                      + SMALL
                    )
                );
        }
    }

    // Correct coupled BCs
    nuf.correctBoundaryConditions();

    return tnu;
}


bool Foam::kineticTheoryModels::frictionalStressModels::Schaeffer::read()
{
    coeffDict_ <<= dict_.optionalSubDict(typeName + "Coeffs");

    phi_.read(coeffDict_);
    phi_ *= degToRad();

    return true;
}


// ************************************************************************* //