contactAngleForce.C

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/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     |
    \\  /    A nd           | www.openfoam.com
     \\/     M anipulation  |
-------------------------------------------------------------------------------
    Copyright (C) 2011-2017 OpenFOAM Foundation
    Copyright (C) 2018-2020 OpenCFD Ltd.
-------------------------------------------------------------------------------
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
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
 
    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    for more details.
 
    You should have received a copy of the GNU General Public License
    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.
 
\*---------------------------------------------------------------------------*/
 
#include "contactAngleForce.H"
#include "addToRunTimeSelectionTable.H"
#include "fvcGrad.H"
#include "unitConversion.H"
#include "meshWavePatchDistMethod.H"
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
namespace Foam
{
namespace regionModels
{
namespace surfaceFilmModels
{
 
// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
 
defineTypeNameAndDebug(contactAngleForce, 0);
 
// * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * * //
 
void contactAngleForce::initialise()
{
    const wordRes zeroForcePatches
    (
        coeffDict_.getOrDefault<wordRes>("zeroForcePatches", wordRes())
    );
 
    if (zeroForcePatches.size())
    {
        const polyBoundaryMesh& pbm = filmModel_.regionMesh().boundaryMesh();
        const scalar dLim = coeffDict_.get<scalar>("zeroForceDistance");
 
        Info<< "        Assigning zero contact force within " << dLim
            << " of patches:" << endl;
 
        labelHashSet patchIDs = pbm.patchSet(zeroForcePatches);
 
        for (const label patchi : patchIDs)
        {
            Info<< "            " << pbm[patchi].name() << endl;
        }
 
        // Temporary implementation until run-time selection covers this case
        patchDistMethods::meshWave dist(filmModel_.regionMesh(), patchIDs);
        volScalarField y
        (
            IOobject
            (
                "y",
                filmModel_.regionMesh().time().timeName(),
                filmModel_.regionMesh(),
                IOobject::NO_READ,
                IOobject::NO_WRITE,
                false
            ),
            filmModel_.regionMesh(),
            dimensionedScalar("y", dimLength, GREAT)
        );
        dist.correct(y);
 
        mask_ = pos0(y - dimensionedScalar("dLim", dimLength, dLim));
    }
}
 
 
// * * * * * * * * * * * * * * * * Constructors  * * * * * * * * * * * * * * //
 
contactAngleForce::contactAngleForce
(
    const word& typeName,
    surfaceFilmRegionModel& film,
    const dictionary& dict
)
:
    force(typeName, film, dict),
    Ccf_(coeffDict_.get<scalar>("Ccf")),
    mask_
    (
        IOobject
        (
            typeName + ":contactForceMask",
            filmModel_.time().timeName(),
            filmModel_.regionMesh(),
            IOobject::NO_READ,
            IOobject::NO_WRITE
        ),
        filmModel_.regionMesh(),
        dimensionedScalar("mask", dimless, 1.0)
    )
{
    initialise();
}
 
 
// * * * * * * * * * * * * * * * * Destructor  * * * * * * * * * * * * * * * //
 
contactAngleForce::~contactAngleForce()
{}
 
 
// * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * * //
 
tmp<fvVectorMatrix> contactAngleForce::correct(volVectorField& U)
{
    tmp<volVectorField> tForce
    (
        new volVectorField
        (
            IOobject
            (
                typeName + ":contactForce",
                filmModel_.time().timeName(),
                filmModel_.regionMesh(),
                IOobject::NO_READ,
                IOobject::NO_WRITE
            ),
            filmModel_.regionMesh(),
            dimensionedVector(dimForce/dimArea, Zero)
        )
    );
 
    vectorField& force = tForce.ref().primitiveFieldRef();
 
    const labelUList& own = filmModel_.regionMesh().owner();
    const labelUList& nbr = filmModel_.regionMesh().neighbour();
 
    const scalarField& magSf = filmModel_.magSf();
 
    const volScalarField& alpha = filmModel_.alpha();
    const volScalarField& sigma = filmModel_.sigma();
 
    const tmp<volScalarField> ttheta = theta();
    const volScalarField& theta = ttheta();
 
    const volVectorField gradAlpha(fvc::grad(alpha));
 
    forAll(nbr, facei)
    {
        const label cellO = own[facei];
        const label cellN = nbr[facei];
 
        label celli = -1;
        if ((alpha[cellO] > 0.5) && (alpha[cellN] < 0.5))
        {
            celli = cellO;
        }
        else if ((alpha[cellO] < 0.5) && (alpha[cellN] > 0.5))
        {
            celli = cellN;
        }
 
        if (celli != -1 && mask_[celli] > 0.5)
        {
            const scalar invDx = filmModel_.regionMesh().deltaCoeffs()[facei];
            const vector n =
                gradAlpha[celli]/(mag(gradAlpha[celli]) + ROOTVSMALL);
            const scalar cosTheta = cos(degToRad(theta[celli]));
            force[celli] += Ccf_*n*sigma[celli]*(1 - cosTheta)/invDx;
        }
    }
 
    forAll(alpha.boundaryField(), patchi)
    {
        if (!filmModel_.isCoupledPatch(patchi))
        {
            const fvPatchField<scalar>& alphaPf = alpha.boundaryField()[patchi];
            const fvPatchField<scalar>& maskPf = mask_.boundaryField()[patchi];
            const fvPatchField<scalar>& sigmaPf = sigma.boundaryField()[patchi];
            const fvPatchField<scalar>& thetaPf = theta.boundaryField()[patchi];
            const scalarField& invDx = alphaPf.patch().deltaCoeffs();
            const labelUList& faceCells = alphaPf.patch().faceCells();
 
            forAll(alphaPf, facei)
            {
                if (maskPf[facei] > 0.5)
                {
                    label cellO = faceCells[facei];
 
                    if ((alpha[cellO] > 0.5) && (alphaPf[facei] < 0.5))
                    {
                        const vector n =
                            gradAlpha[cellO]
                           /(mag(gradAlpha[cellO]) + ROOTVSMALL);
                        const scalar cosTheta = cos(degToRad(thetaPf[facei]));
                        force[cellO] +=
                            Ccf_*n*sigmaPf[facei]*(1 - cosTheta)/invDx[facei];
                    }
                }
            }
        }
    }
 
    force /= magSf;
 
    if (filmModel_.regionMesh().time().writeTime())
    {
        tForce().write();
    }
 
    tmp<fvVectorMatrix> tfvm
    (
        new fvVectorMatrix(U, dimForce/dimArea*dimVolume)
    );
 
    tfvm.ref() += tForce;
 
    return tfvm;
}
 
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
} // End namespace surfaceFilmModels
} // End namespace regionModels
} // End namespace Foam
 
// ************************************************************************* //