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fc6b44ee3cd8ff7ea89b8edb4f4470247612fffb
openfoam/applications/solvers/multiphase/twoPhaseEulerFoam/twoPhaseSystem/twoPhaseSystem.C
Henry fc6b44ee3c twoPhaseEulerFoam: Added experimental face-based momentum equation formulation 
This formulation provides C-grid like pressure-flux staggering on an
unstructured mesh which is hugely beneficial for Euler-Euler multiphase
equations as it allows for all forces to be treated in a consistent
manner on the cell-faces which provides better balance, stability and
accuracy.  However, to achieve face-force consistency the momentum
transport terms must be interpolated to the faces reducing accuracy of
this part of the system but this is offset by the increase in accuracy
of the force-balance.

Currently it is not clear if this face-based momentum equation
formulation is preferable for all Euler-Euler simulations so I have
included it on a switch to allow evaluation and comparison with the
previous cell-based formulation.  To try the new algorithm simply switch
it on, e.g.:

PIMPLE
{
    nOuterCorrectors 3;
    nCorrectors      1;
    nNonOrthogonalCorrectors 0;
    faceMomentum     yes;
}

It is proving particularly good for bubbly flows, eliminating the
staggering patterns often seen in the air velocity field with the
previous algorithm, removing other spurious numerical artifacts in the
velocity fields and improving stability and allowing larger time-steps
For particle-gas flows the advantage is noticeable but not nearly as
pronounced as in the bubbly flow cases.

Please test the new algorithm on your cases and provide feedback.

Henry G. Weller
CFD Direct
2015-04-27 21:33:58 +01:00

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/*---------------------------------------------------------------------------*\
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | Copyright (C) 2013-2015 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 "twoPhaseSystem.H"
#include "PhaseCompressibleTurbulenceModel.H"
#include "BlendedInterfacialModel.H"
#include "virtualMassModel.H"
#include "heatTransferModel.H"
#include "liftModel.H"
#include "wallLubricationModel.H"
#include "turbulentDispersionModel.H"
#include "fvMatrix.H"
#include "surfaceInterpolate.H"
#include "MULES.H"
#include "subCycle.H"
#include "fvcDdt.H"
#include "fvcDiv.H"
#include "fvcSnGrad.H"
#include "fvcFlux.H"
#include "fvcCurl.H"
#include "fvmDdt.H"
#include "fvmLaplacian.H"
#include "fixedValueFvsPatchFields.H"
#include "blendingMethod.H"
#include "HashPtrTable.H"
// * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
Foam::dimensionedScalar Foam::twoPhaseSystem::zeroResidualAlpha_
(
"zeroResidualAlpha", dimless, 0
);
// * * * * * * * * * * * * * * * * Constructors * * * * * * * * * * * * * * //
Foam::twoPhaseSystem::twoPhaseSystem
(
const fvMesh& mesh,
const dimensionedVector& g
)
:
IOdictionary
(
IOobject
(
"phaseProperties",
mesh.time().constant(),
mesh,
IOobject::MUST_READ_IF_MODIFIED,
IOobject::NO_WRITE
)
),
mesh_(mesh),
phase1_
(
*this,
*this,
wordList(lookup("phases"))[0]
),
phase2_
(
*this,
*this,
wordList(lookup("phases"))[1]
),
phi_
(
IOobject
(
"phi",
mesh.time().timeName(),
mesh,
IOobject::NO_READ,
IOobject::AUTO_WRITE
),
this->calcPhi()
),
dgdt_
(
IOobject
(
"dgdt",
mesh.time().timeName(),
mesh,
IOobject::READ_IF_PRESENT,
IOobject::AUTO_WRITE
),
mesh,
dimensionedScalar("dgdt", dimless/dimTime, 0)
)
{
phase2_.volScalarField::operator=(scalar(1) - phase1_);
// Blending
forAllConstIter(dictionary, subDict("blending"), iter)
{
blendingMethods_.insert
(
iter().dict().dictName(),
blendingMethod::New
(
iter().dict(),
wordList(lookup("phases"))
)
);
}
// Pairs
phasePair::scalarTable sigmaTable(lookup("sigma"));
phasePair::dictTable aspectRatioTable(lookup("aspectRatio"));
pair_.set
(
new phasePair
(
phase1_,
phase2_,
g,
sigmaTable
)
);
pair1In2_.set
(
new orderedPhasePair
(
phase1_,
phase2_,
g,
sigmaTable,
aspectRatioTable
)
);
pair2In1_.set
(
new orderedPhasePair
(
phase2_,
phase1_,
g,
sigmaTable,
aspectRatioTable
)
);
// Models
drag_.set
(
new BlendedInterfacialModel<dragModel>
(
lookup("drag"),
(
blendingMethods_.found("drag")
? blendingMethods_["drag"]
: blendingMethods_["default"]
),
pair_,
pair1In2_,
pair2In1_,
false // Do not zero drag coefficent at fixed-flux BCs
)
);
virtualMass_.set
(
new BlendedInterfacialModel<virtualMassModel>
(
lookup("virtualMass"),
(
blendingMethods_.found("virtualMass")
? blendingMethods_["virtualMass"]
: blendingMethods_["default"]
),
pair_,
pair1In2_,
pair2In1_
)
);
heatTransfer_.set
(
new BlendedInterfacialModel<heatTransferModel>
(
lookup("heatTransfer"),
(
blendingMethods_.found("heatTransfer")
? blendingMethods_["heatTransfer"]
: blendingMethods_["default"]
),
pair_,
pair1In2_,
pair2In1_
)
);
lift_.set
(
new BlendedInterfacialModel<liftModel>
(
lookup("lift"),
(
blendingMethods_.found("lift")
? blendingMethods_["lift"]
: blendingMethods_["default"]
),
pair_,
pair1In2_,
pair2In1_
)
);
wallLubrication_.set
(
new BlendedInterfacialModel<wallLubricationModel>
(
lookup("wallLubrication"),
(
blendingMethods_.found("wallLubrication")
? blendingMethods_["wallLubrication"]
: blendingMethods_["default"]
),
pair_,
pair1In2_,
pair2In1_
)
);
turbulentDispersion_.set
(
new BlendedInterfacialModel<turbulentDispersionModel>
(
lookup("turbulentDispersion"),
(
blendingMethods_.found("turbulentDispersion")
? blendingMethods_["turbulentDispersion"]
: blendingMethods_["default"]
),
pair_,
pair1In2_,
pair2In1_
)
);
}
// * * * * * * * * * * * * * * * * Destructor * * * * * * * * * * * * * * * //
Foam::twoPhaseSystem::~twoPhaseSystem()
{}
// * * * * * * * * * * * * * * Member Functions * * * * * * * * * * * * * * //
Foam::tmp<Foam::volScalarField> Foam::twoPhaseSystem::rho() const
{
return phase1_*phase1_.thermo().rho() + phase2_*phase2_.thermo().rho();
}
Foam::tmp<Foam::volVectorField> Foam::twoPhaseSystem::U() const
{
return phase1_*phase1_.U() + phase2_*phase2_.U();
}
Foam::tmp<Foam::surfaceScalarField> Foam::twoPhaseSystem::calcPhi() const
{
return
fvc::interpolate(phase1_)*phase1_.phi()
+ fvc::interpolate(phase2_)*phase2_.phi();
}
Foam::tmp<Foam::volScalarField> Foam::twoPhaseSystem::Kd() const
{
return drag_->K();
}
Foam::tmp<Foam::surfaceScalarField> Foam::twoPhaseSystem::Kdf() const
{
return drag_->Kf();
}
Foam::tmp<Foam::volScalarField> Foam::twoPhaseSystem::Vm() const
{
return virtualMass_->K();
}
Foam::tmp<Foam::surfaceScalarField> Foam::twoPhaseSystem::Vmf() const
{
return virtualMass_->Kf();
}
Foam::tmp<Foam::volScalarField> Foam::twoPhaseSystem::Kh() const
{
return heatTransfer_->K();
}
Foam::tmp<Foam::volVectorField> Foam::twoPhaseSystem::F() const
{
return lift_->F<vector>() + wallLubrication_->F<vector>();
}
Foam::tmp<Foam::surfaceScalarField> Foam::twoPhaseSystem::Ff() const
{
return lift_->Ff() + wallLubrication_->Ff();
}
Foam::tmp<Foam::volScalarField> Foam::twoPhaseSystem::D() const
{
return turbulentDispersion_->D();
}
void Foam::twoPhaseSystem::solve()
{
const Time& runTime = mesh_.time();
volScalarField& alpha1 = phase1_;
volScalarField& alpha2 = phase2_;
const surfaceScalarField& phi1 = phase1_.phi();
const surfaceScalarField& phi2 = phase2_.phi();
Switch faceMomentum
(
//pimple.dict().lookupOrDefault<Switch>("faceMomentum", false)
mesh_.solutionDict().subDict("PIMPLE")
.lookupOrDefault<Switch>("faceMomentum", false)
);
const dictionary& alphaControls = mesh_.solverDict
(
alpha1.name()
);
label nAlphaSubCycles(readLabel(alphaControls.lookup("nAlphaSubCycles")));
label nAlphaCorr(readLabel(alphaControls.lookup("nAlphaCorr")));
Switch implicitPhasePressure
(
alphaControls.lookupOrDefault<Switch>("implicitPhasePressure", false)
);
word alphaScheme("div(phi," + alpha1.name() + ')');
word alpharScheme("div(phir," + alpha1.name() + ')');
alpha1.correctBoundaryConditions();
surfaceScalarField phic("phic", phi_);
surfaceScalarField phir("phir", phi1 - phi2);
surfaceScalarField alpha1f(fvc::interpolate(max(alpha1, scalar(0))));
tmp<surfaceScalarField> pPrimeByA;
if (implicitPhasePressure)
{
if (faceMomentum)
{
const surfaceScalarField& rAU1f =
mesh_.lookupObject<surfaceScalarField>
(
IOobject::groupName("rAUf", phase1_.name())
);
const surfaceScalarField& rAU2f =
mesh_.lookupObject<surfaceScalarField>
(
IOobject::groupName("rAUf", phase2_.name())
);
volScalarField D(this->D());
pPrimeByA =
rAU1f*fvc::interpolate(D + phase1_.turbulence().pPrime())
+ rAU2f*fvc::interpolate(D + phase2_.turbulence().pPrime());
}
else
{
const volScalarField& rAU1 = mesh_.lookupObject<volScalarField>
(
IOobject::groupName("rAU", phase1_.name())
);
const volScalarField& rAU2 = mesh_.lookupObject<volScalarField>
(
IOobject::groupName("rAU", phase2_.name())
);
pPrimeByA =
fvc::interpolate(rAU1*phase1_.turbulence().pPrime())
+ fvc::interpolate(rAU2*phase2_.turbulence().pPrime());
}
surfaceScalarField phiP
(
pPrimeByA()*fvc::snGrad(alpha1, "bounded")*mesh_.magSf()
);
phic += alpha1f*phiP;
phir += phiP;
}
for (int acorr=0; acorr<nAlphaCorr; acorr++)
{
volScalarField::DimensionedInternalField Sp
(
IOobject
(
"Sp",
runTime.timeName(),
mesh_
),
mesh_,
dimensionedScalar("Sp", dgdt_.dimensions(), 0.0)
);
volScalarField::DimensionedInternalField Su
(
IOobject
(
"Su",
runTime.timeName(),
mesh_
),
// Divergence term is handled explicitly to be
// consistent with the explicit transport solution
fvc::div(phi_)*min(alpha1, scalar(1))
);
forAll(dgdt_, celli)
{
if (dgdt_[celli] > 0.0)
{
Sp[celli] -= dgdt_[celli]/max(1.0 - alpha1[celli], 1e-4);
Su[celli] += dgdt_[celli]/max(1.0 - alpha1[celli], 1e-4);
}
else if (dgdt_[celli] < 0.0)
{
Sp[celli] += dgdt_[celli]/max(alpha1[celli], 1e-4);
}
}
surfaceScalarField alphaPhic1
(
fvc::flux
(
phic,
alpha1,
alphaScheme
)
+ fvc::flux
(
-fvc::flux(-phir, scalar(1) - alpha1, alpharScheme),
alpha1,
alpharScheme
)
);
// Ensure that the flux at inflow BCs is preserved
forAll(alphaPhic1.boundaryField(), patchi)
{
fvsPatchScalarField& alphaPhic1p =
alphaPhic1.boundaryField()[patchi];
if (!alphaPhic1p.coupled())
{
const scalarField& phi1p = phi1.boundaryField()[patchi];
const scalarField& alpha1p = alpha1.boundaryField()[patchi];
forAll(alphaPhic1p, facei)
{
if (phi1p[facei] < 0)
{
alphaPhic1p[facei] = alpha1p[facei]*phi1p[facei];
}
}
}
}
if (nAlphaSubCycles > 1)
{
for
(
subCycle<volScalarField> alphaSubCycle(alpha1, nAlphaSubCycles);
!(++alphaSubCycle).end();
)
{
surfaceScalarField alphaPhic10(alphaPhic1);
MULES::explicitSolve
(
geometricOneField(),
alpha1,
phi_,
alphaPhic10,
(alphaSubCycle.index()*Sp)(),
(Su - (alphaSubCycle.index() - 1)*Sp*alpha1)(),
phase1_.alphaMax(),
0
);
if (alphaSubCycle.index() == 1)
{
phase1_.alphaPhi() = alphaPhic10;
}
else
{
phase1_.alphaPhi() += alphaPhic10;
}
}
phase1_.alphaPhi() /= nAlphaSubCycles;
}
else
{
MULES::explicitSolve
(
geometricOneField(),
alpha1,
phi_,
alphaPhic1,
Sp,
Su,
phase1_.alphaMax(),
0
);
phase1_.alphaPhi() = alphaPhic1;
}
if (implicitPhasePressure)
{
fvScalarMatrix alpha1Eqn
(
fvm::ddt(alpha1) - fvc::ddt(alpha1)
- fvm::laplacian(alpha1f*pPrimeByA(), alpha1, "bounded")
);
alpha1Eqn.relax();
alpha1Eqn.solve();
phase1_.alphaPhi() += alpha1Eqn.flux();
}
phase1_.alphaRhoPhi() =
fvc::interpolate(phase1_.rho())*phase1_.alphaPhi();
phase2_.alphaPhi() = phi_ - phase1_.alphaPhi();
alpha2 = scalar(1) - alpha1;
phase2_.alphaRhoPhi() =
fvc::interpolate(phase2_.rho())*phase2_.alphaPhi();
Info<< alpha1.name() << " volume fraction = "
<< alpha1.weightedAverage(mesh_.V()).value()
<< " Min(" << alpha1.name() << ") = " << min(alpha1).value()
<< " Max(" << alpha1.name() << ") = " << max(alpha1).value()
<< endl;
}
}
void Foam::twoPhaseSystem::correct()
{
phase1_.correct();
phase2_.correct();
}
void Foam::twoPhaseSystem::correctTurbulence()
{
phase1_.turbulence().correct();
phase2_.turbulence().correct();
}
bool Foam::twoPhaseSystem::read()
{
if (regIOobject::read())
{
bool readOK = true;
readOK &= phase1_.read(*this);
readOK &= phase2_.read(*this);
// models ...
return readOK;
}
else
{
return false;
}
}
const Foam::dimensionedScalar&
Foam::twoPhaseSystem::residualAlpha(const phaseModel& phase) const
{
if (drag_->hasModel(phase))
{
return drag_->phaseModel(phase).residualAlpha();
}
else
{
return zeroResidualAlpha_;
}
}
const Foam::dragModel& Foam::twoPhaseSystem::drag(const phaseModel& phase) const
{
return drag_->phaseModel(phase);
}
const Foam::virtualMassModel&
Foam::twoPhaseSystem::virtualMass(const phaseModel& phase) const
{
return virtualMass_->phaseModel(phase);
}
const Foam::dimensionedScalar& Foam::twoPhaseSystem::sigma() const
{
return pair_->sigma();
}
// ************************************************************************* //
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