momentumPredictor.C

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License
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#include "isothermalFilm.H"
#include "surfaceTensionModel.H"
#include "fvmDiv.H"
#include "fvcSnGrad.H"
#include "fvcLaplacian.H"
#include "fvcReconstruct.H"
 
// * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * * //
 
Foam::tmp<Foam::volScalarField>
Foam::solvers::isothermalFilm::sigma() const
{
    return constrainedField(surfaceTension->sigma());
}
 
 
Foam::tmp<Foam::surfaceScalarField>
Foam::solvers::isothermalFilm::pbByAlphaRhof() const
{
    return fvc::interpolate
    (
        max(nHat & g, dimensionedScalar(g.dimensions(), 0))*VbyA
    );
}
 
 
Foam::tmp<Foam::surfaceScalarField>
Foam::solvers::isothermalFilm::pbByAlphaf() const
{
    return fvc::interpolate(rho)*pbByAlphaRhof();
}
 
 
Foam::tmp<Foam::surfaceScalarField>
Foam::solvers::isothermalFilm::pbByAlphaGradRhof() const
{
    return pbByAlphaRhof()*fvc::snGrad(rho);
}
 
 
Foam::tmp<Foam::volScalarField>
Foam::solvers::isothermalFilm::pc(const volScalarField& sigma) const
{
    return -fvc::laplacian(sigma, delta);
}
 
 
Foam::tmp<Foam::volScalarField>
Foam::solvers::isothermalFilm::pe() const
{
    // Update the pressure, mapping from the fluid region as required
    p.correctBoundaryConditions();
 
    // Add the droplet impingement pressure
    p.ref() += mesh.time().deltaT()*fvModels().source(p, "pi")().Su();
 
    return p;
}
 
 
void Foam::solvers::isothermalFilm::momentumPredictor()
{
    volVectorField& U = U_;
 
    // Calculate the surface tension coefficient
    const volScalarField sigma(this->sigma());
 
    tUEqn =
    (
        fvm::ddt(alpha, rho, U) + fvm::div(alphaRhoPhi, U)
      - fvm::Sp(contErr(), U)
      + momentumTransport->divDevTau(U)
     ==
        contactForce(sigma)
      + fvModels().source(alpha, rho, U)
    );
    fvVectorMatrix& UEqn = tUEqn.ref();
 
    // Thermocapillary force
    if (thermocapillary)
    {
        UEqn -= fvc::grad(sigma)/VbyA;
    }
 
    UEqn.relax();
 
    fvConstraints().constrain(UEqn);
 
    if (pimple.momentumPredictor())
    {
        const surfaceScalarField alphaf(fvc::interpolate(alpha));
 
        solve
        (
            UEqn
         ==
            fvc::reconstruct
            (
                constrainedField
                (
                    alphaf
                   *(
                        // Buoyancy force
                        fvc::interpolate(rho)*(g & mesh.Sf())
 
                      - (
                            // External and capillary pressure
                            fvc::snGrad(pe() + pc(sigma), "snGrad(p)")
 
                            // Buoyant pressure
                          + pbByAlphaGradRhof()*alphaf
                          + pbByAlphaf()*fvc::snGrad(alpha)
                        )*mesh.magSf()
                    )
                )
            )
        );
 
        // Remove film-normal component of velocity
        U -= nHat*(nHat & U);
 
        U.correctBoundaryConditions();
    }
}
 
 
// ************************************************************************* //