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========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration | Website: https://openfoam.org
\\ / A nd | Copyright (C) 2011-2026 OpenFOAM Foundation
\\/ M anipulation |
-------------------------------------------------------------------------------
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 "interfaceProperties.H"
#include "contactAngleFvPatchScalarField.H"
#include "surfaceInterpolate.H"
#include "fvcDiv.H"
#include "fvcGrad.H"
#include "fvcSnGrad.H"
// * * * * * * * * * * * * * Private Member Functions * * * * * * * * * * * //
// Correction for the boundary condition on the unit normal nHat on
// walls to produce the correct contact angle.
// The dynamic contact angle is calculated from the component of the
// velocity on the direction of the interface, parallel to the wall.
void Foam::interfaceProperties::correctContactAngle
(
surfaceVectorField::BoundaryField& nHatb,
const surfaceVectorField::BoundaryField& gradAlphaf
)
{
const fvMesh& mesh = alpha1_.mesh();
volScalarField::BoundaryField& a1bf = alpha1_.boundaryFieldRef();
volScalarField::BoundaryField& a2bf = alpha2_.boundaryFieldRef();
const fvBoundaryMesh& boundary = mesh.boundary();
forAll(boundary, patchi)
{
if (isA<contactAngleFvPatchScalarField>(a1bf[patchi]))
{
contactAngleFvPatchScalarField& a1cap =
refCast<contactAngleFvPatchScalarField>
(
a1bf[patchi]
);
fvsPatchVectorField& nHatp = nHatb[patchi];
const scalarField cosTheta
(
a1cap.cosTheta(U_.boundaryField()[patchi], nHatp)
);
const vectorField nf
(
boundary[patchi].nf()
);
// Reset nHatp to correspond to the contact angle
const scalarField a12(nHatp & nf);
const scalarField b1(cosTheta);
scalarField b2(nHatp.size());
forAll(b2, facei)
{
b2[facei] = cos(acos(a12[facei]) - acos(cosTheta[facei]));
}
const scalarField det(1.0 - a12*a12);
scalarField a((b1 - a12*b2)/det);
scalarField b((b2 - a12*b1)/det);
nHatp = a*nf + b*nHatp;
nHatp /= (mag(nHatp) + deltaN_.value());
a1cap.gradient() = (nf & nHatp)*mag(gradAlphaf[patchi]);
a1cap.evaluate();
a2bf[patchi] = 1 - a1cap.field();
}
}
}
void Foam::interfaceProperties::calculateK()
{
const fvMesh& mesh = alpha1_.mesh();
const surfaceVectorField& Sf = mesh.Sf();
// Cell gradient of alpha
const volVectorField gradAlpha(fvc::grad(alpha1_, "nHat"));
// Interpolated face-gradient of alpha
surfaceVectorField gradAlphaf(fvc::interpolate(gradAlpha));
// gradAlphaf -=
// (mesh.Sf()/mesh.magSf())
// *(fvc::snGrad(alpha1_) - (mesh.Sf() & gradAlphaf)/mesh.magSf());
// Face unit interface normal
surfaceVectorField nHatfv(gradAlphaf/(mag(gradAlphaf) + deltaN_));
// surfaceVectorField nHatfv
// (
// (gradAlphaf + deltaN_*vector(0, 0, 1)
// *sign(gradAlphaf.component(vector::Z)))/(mag(gradAlphaf) + deltaN_)
// );
correctContactAngle(nHatfv.boundaryFieldRef(), gradAlphaf.boundaryField());
// Face unit interface normal flux
nHatf_ = nHatfv & Sf;
// Simple expression for curvature
K_ = -fvc::div(nHatf_);
// Complex expression for curvature.
// Correction is formally zero but numerically non-zero.
/*
volVectorField nHat(gradAlpha/(mag(gradAlpha) + deltaN_));
forAll(nHat.boundaryField(), patchi)
{
nHat.boundaryField()[patchi] = nHatfv.boundaryField()[patchi];
}
K_ = -fvc::div(nHatf_) + (nHat & fvc::grad(nHatfv) & nHat);
*/
}
// * * * * * * * * * * * * * * * * Constructors * * * * * * * * * * * * * * //
Foam::interfaceProperties::interfaceProperties
(
const IOdictionary& dict,
volScalarField& alpha1,
volScalarField& alpha2,
const volVectorField& U
)
:
phasePropertiesDict_(dict),
alpha1_(alpha1),
alpha2_(alpha2),
U_(U),
sigmaPtr_(surfaceTensionModel::New(dict, alpha1.mesh())),
deltaN_
(
"deltaN",
1e-8/pow(average(alpha1.mesh().V()), 1.0/3.0)
),
nHatf_
(
IOobject
(
"nHatf",
alpha1_.time().name(),
alpha1_.mesh()
),
alpha1_.mesh(),
dimensionedScalar(dimensions::area, 0)
),
K_
(
IOobject
(
"interfaceProperties:K",
alpha1_.time().name(),
alpha1_.mesh()
),
alpha1_.mesh(),
dimensionedScalar(inv(dimensions::length), 0)
)
{
calculateK();
}
// * * * * * * * * * * * * * * Member Functions * * * * * * * * * * * * * * //
Foam::tmp<Foam::volVectorField> Foam::interfaceProperties::n() const
{
const volVectorField gradAlpha(fvc::grad(alpha1_));
return volVectorField::New("n", gradAlpha/(mag(gradAlpha) + deltaN_));
}
Foam::tmp<Foam::volScalarField>
Foam::interfaceProperties::sigmaK() const
{
return sigmaPtr_->sigma()*K_;
}
Foam::tmp<Foam::surfaceScalarField>
Foam::interfaceProperties::surfaceTensionForce() const
{
return fvc::interpolate(sigmaK())*fvc::snGrad(alpha1_);
}
Foam::tmp<Foam::volScalarField>
Foam::interfaceProperties::nearInterface() const
{
return pos0(alpha1_ - 0.01)*pos0(0.99 - alpha1_);
}
void Foam::interfaceProperties::correct()
{
calculateK();
}
bool Foam::interfaceProperties::read()
{
sigmaPtr_->readDict(phasePropertiesDict_);
return true;
}
// ************************************************************************* //
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