Commit ad92287a authored by Henry Weller's avatar Henry Weller
Browse files

Multi-phase solvers: Improved handling of inflow/outflow BCs in MULES

Avoids slight phase-fraction unboundedness at entertainment BCs and improved
robustness.

Additionally the phase-fractions in the multi-phase (rather than two-phase)
solvers are adjusted to avoid the slow growth of inconsistency ("drift") caused
by solving for all of the phase-fractions rather than deriving one from the
others.
parent 8b930836
......@@ -2,7 +2,7 @@
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | Copyright (C) 2011-2016 OpenFOAM Foundation
\\ / A nd | Copyright (C) 2011-2017 OpenFOAM Foundation
\\/ M anipulation |
-------------------------------------------------------------------------------
License
......@@ -64,11 +64,8 @@ void Foam::multiphaseSystem::solveAlphas()
forAllIter(PtrDictionary<phaseModel>, phases_, iter)
{
phaseModel& phase1 = iter();
volScalarField& alpha1 = phase1;
phase1.alphaPhi() =
dimensionedScalar("0", dimensionSet(0, 3, -1, 0, 0), 0);
phaseModel& phase = iter();
volScalarField& alpha1 = phase;
alphaPhiCorrs.set
(
......@@ -79,7 +76,7 @@ void Foam::multiphaseSystem::solveAlphas()
fvc::flux
(
phi_,
phase1,
phase,
"div(phi," + alpha1.name() + ')'
)
)
......@@ -92,13 +89,13 @@ void Foam::multiphaseSystem::solveAlphas()
phaseModel& phase2 = iter2();
volScalarField& alpha2 = phase2;
if (&phase2 == &phase1) continue;
if (&phase2 == &phase) continue;
surfaceScalarField phir(phase1.phi() - phase2.phi());
surfaceScalarField phir(phase.phi() - phase2.phi());
scalarCoeffSymmTable::const_iterator cAlpha
(
cAlphas_.find(interfacePair(phase1, phase2))
cAlphas_.find(interfacePair(phase, phase2))
);
if (cAlpha != cAlphas_.end())
......@@ -108,7 +105,7 @@ void Foam::multiphaseSystem::solveAlphas()
(mag(phi_) + mag(phir))/mesh_.magSf()
);
phir += min(cAlpha()*phic, max(phic))*nHatf(phase1, phase2);
phir += min(cAlpha()*phic, max(phic))*nHatf(phase, phase2);
}
word phirScheme
......@@ -119,39 +116,18 @@ void Foam::multiphaseSystem::solveAlphas()
alphaPhiCorr += fvc::flux
(
-fvc::flux(-phir, phase2, phirScheme),
phase1,
phase,
phirScheme
);
}
surfaceScalarField::Boundary& alphaPhiCorrBf =
alphaPhiCorr.boundaryFieldRef();
// Ensure that the flux at inflow BCs is preserved
forAll(alphaPhiCorrBf, patchi)
{
fvsPatchScalarField& alphaPhiCorrp = alphaPhiCorrBf[patchi];
if (!alphaPhiCorrp.coupled())
{
const scalarField& phi1p = phase1.phi().boundaryField()[patchi];
const scalarField& alpha1p = alpha1.boundaryField()[patchi];
forAll(alphaPhiCorrp, facei)
{
if (phi1p[facei] < 0)
{
alphaPhiCorrp[facei] = alpha1p[facei]*phi1p[facei];
}
}
}
}
phase.correctInflowOutflow(alphaPhiCorr);
MULES::limit
(
1.0/mesh_.time().deltaT().value(),
geometricOneField(),
phase1,
phase,
phi_,
alphaPhiCorr,
zeroField(),
......@@ -182,29 +158,30 @@ void Foam::multiphaseSystem::solveAlphas()
forAllIter(PtrDictionary<phaseModel>, phases_, iter)
{
phaseModel& phase1 = iter();
phaseModel& phase = iter();
surfaceScalarField& alphaPhi = alphaPhiCorrs[phasei];
alphaPhi += upwind<scalar>(mesh_, phi_).flux(phase1);
alphaPhi += upwind<scalar>(mesh_, phi_).flux(phase);
phase.correctInflowOutflow(alphaPhi);
MULES::explicitSolve
(
geometricOneField(),
phase1,
phase,
alphaPhi,
zeroField(),
zeroField()
);
phase1.alphaPhi() += alphaPhi;
phase.alphaPhi() = alphaPhi;
Info<< phase1.name() << " volume fraction, min, max = "
<< phase1.weightedAverage(mesh_.V()).value()
<< ' ' << min(phase1).value()
<< ' ' << max(phase1).value()
Info<< phase.name() << " volume fraction, min, max = "
<< phase.weightedAverage(mesh_.V()).value()
<< ' ' << min(phase).value()
<< ' ' << max(phase).value()
<< endl;
sumAlpha += phase1;
sumAlpha += phase;
phasei++;
}
......@@ -215,6 +192,15 @@ void Foam::multiphaseSystem::solveAlphas()
<< ' ' << max(sumAlpha).value()
<< endl;
// Correct the sum of the phase-fractions to avoid 'drift'
volScalarField sumCorr(1.0 - sumAlpha);
forAllIter(PtrDictionary<phaseModel>, phases_, iter)
{
phaseModel& phase = iter();
volScalarField& alpha = phase;
alpha += alpha*sumCorr;
}
calcAlphas();
}
......
......@@ -2,7 +2,7 @@
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | Copyright (C) 2011-2016 OpenFOAM Foundation
\\ / A nd | Copyright (C) 2011-2017 OpenFOAM Foundation
\\/ M anipulation |
-------------------------------------------------------------------------------
License
......@@ -236,6 +236,24 @@ bool Foam::phaseModel::read(const dictionary& phaseDict)
}
void Foam::phaseModel::correctInflowOutflow(surfaceScalarField& alphaPhi) const
{
surfaceScalarField::Boundary& alphaPhiBf = alphaPhi.boundaryFieldRef();
const volScalarField::Boundary& alphaBf = boundaryField();
const surfaceScalarField::Boundary& phiBf = phi().boundaryField();
forAll(alphaPhiBf, patchi)
{
fvsPatchScalarField& alphaPhip = alphaPhiBf[patchi];
if (!alphaPhip.coupled())
{
alphaPhip = phiBf[patchi]*alphaBf[patchi];
}
}
}
Foam::tmp<Foam::volScalarField> Foam::phaseModel::d() const
{
return dPtr_().d();
......
......@@ -2,7 +2,7 @@
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | Copyright (C) 2011-2015 OpenFOAM Foundation
\\ / A nd | Copyright (C) 2011-2017 OpenFOAM Foundation
\\/ M anipulation |
-------------------------------------------------------------------------------
License
......@@ -208,6 +208,9 @@ public:
return alphaPhi_;
}
//- Ensure that the flux at inflow/outflow BCs is preserved
void correctInflowOutflow(surfaceScalarField& alphaPhi) const;
//- Correct the phase properties
void correct();
......
......@@ -2,7 +2,7 @@
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | Copyright (C) 2011-2016 OpenFOAM Foundation
\\ / A nd | Copyright (C) 2011-2017 OpenFOAM Foundation
\\/ M anipulation |
-------------------------------------------------------------------------------
License
......@@ -681,6 +681,14 @@ void Foam::multiphaseMixture::solveAlphas
<< ' ' << max(sumAlpha).value()
<< endl;
// Correct the sum of the phase-fractions to avoid 'drift'
volScalarField sumCorr(1.0 - sumAlpha);
forAllIter(PtrDictionary<phase>, phases_, iter)
{
phase& alpha = iter();
alpha += alpha*sumCorr;
}
calcAlphas();
}
......
......@@ -2,7 +2,7 @@
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | Copyright (C) 2015-2016 OpenFOAM Foundation
\\ / A nd | Copyright (C) 2015-2017 OpenFOAM Foundation
\\/ M anipulation |
-------------------------------------------------------------------------------
License
......@@ -165,6 +165,24 @@ bool Foam::phaseModel::compressible() const
}
void Foam::phaseModel::correctInflowOutflow(surfaceScalarField& alphaPhi) const
{
surfaceScalarField::Boundary& alphaPhiBf = alphaPhi.boundaryFieldRef();
const volScalarField::Boundary& alphaBf = boundaryField();
const surfaceScalarField::Boundary& phiBf = phi()().boundaryField();
forAll(alphaPhiBf, patchi)
{
fvsPatchScalarField& alphaPhip = alphaPhiBf[patchi];
if (!alphaPhip.coupled())
{
alphaPhip = phiBf[patchi]*alphaBf[patchi];
}
}
}
const Foam::tmp<Foam::volScalarField>& Foam::phaseModel::divU() const
{
NotImplemented;
......
......@@ -2,7 +2,7 @@
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | Copyright (C) 2015 OpenFOAM Foundation
\\ / A nd | Copyright (C) 2015-2017 OpenFOAM Foundation
\\/ M anipulation |
-------------------------------------------------------------------------------
License
......@@ -283,6 +283,9 @@ public:
//- Access the mass flux of the phase
virtual surfaceScalarField& alphaRhoPhi() = 0;
//- Ensure that the flux at inflow/outflow BCs is preserved
void correctInflowOutflow(surfaceScalarField& alphaPhi) const;
// Transport
......
......@@ -2,7 +2,7 @@
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | Copyright (C) 2013-2016 OpenFOAM Foundation
\\ / A nd | Copyright (C) 2013-2017 OpenFOAM Foundation
\\/ M anipulation |
-------------------------------------------------------------------------------
License
......@@ -71,15 +71,17 @@ void Foam::multiphaseSystem::solveAlphas()
{
bool LTS = fv::localEulerDdt::enabled(mesh_);
forAll(phases(), phasei)
{
phases()[phasei].correctBoundaryConditions();
}
PtrList<surfaceScalarField> alphaPhiCorrs(phases().size());
forAll(phases(), phasei)
{
phaseModel& phase = phases()[phasei];
volScalarField& alpha1 = phase;
phase.alphaPhi() =
dimensionedScalar("0", dimensionSet(0, 3, -1, 0, 0), 0);
alphaPhiCorrs.set
(
phasei,
......@@ -134,28 +136,7 @@ void Foam::multiphaseSystem::solveAlphas()
);
}
surfaceScalarField::Boundary& alphaPhiCorrBf =
alphaPhiCorr.boundaryFieldRef();
// Ensure that the flux at inflow BCs is preserved
forAll(alphaPhiCorr.boundaryField(), patchi)
{
fvsPatchScalarField& alphaPhiCorrp = alphaPhiCorrBf[patchi];
if (!alphaPhiCorrp.coupled())
{
const scalarField& phi1p = phase.phi().boundaryField()[patchi];
const scalarField& alpha1p = alpha1.boundaryField()[patchi];
forAll(alphaPhiCorrp, facei)
{
if (phi1p[facei] < 0)
{
alphaPhiCorrp[facei] = alpha1p[facei]*phi1p[facei];
}
}
}
}
phase.correctInflowOutflow(alphaPhiCorr);
if (LTS)
{
......@@ -215,8 +196,9 @@ void Foam::multiphaseSystem::solveAlphas()
phaseModel& phase = phases()[phasei];
volScalarField& alpha = phase;
surfaceScalarField& alphaPhic = alphaPhiCorrs[phasei];
alphaPhic += upwind<scalar>(mesh_, phi_).flux(phase);
surfaceScalarField& alphaPhi = alphaPhiCorrs[phasei];
alphaPhi += upwind<scalar>(mesh_, phi_).flux(phase);
phase.correctInflowOutflow(alphaPhi);
volScalarField::Internal Sp
(
......@@ -298,12 +280,12 @@ void Foam::multiphaseSystem::solveAlphas()
(
geometricOneField(),
alpha,
alphaPhic,
alphaPhi,
Sp,
Su
);
phase.alphaPhi() += alphaPhic;
phase.alphaPhi() = alphaPhi;
Info<< phase.name() << " volume fraction, min, max = "
<< phase.weightedAverage(mesh_.V()).value()
......@@ -319,6 +301,14 @@ void Foam::multiphaseSystem::solveAlphas()
<< ' ' << min(sumAlpha).value()
<< ' ' << max(sumAlpha).value()
<< endl;
// Correct the sum of the phase-fractions to avoid 'drift'
volScalarField sumCorr(1.0 - sumAlpha);
forAll(phases(), phasei)
{
volScalarField& alpha = phases()[phasei];
alpha += alpha*sumCorr;
}
}
......
......@@ -2,7 +2,7 @@
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | Copyright (C) 2013-2016 OpenFOAM Foundation
\\ / A nd | Copyright (C) 2013-2017 OpenFOAM Foundation
\\/ M anipulation |
-------------------------------------------------------------------------------
License
......@@ -201,7 +201,6 @@ void Foam::twoPhaseSystem::solve()
word alphaScheme("div(phi," + alpha1.name() + ')');
word alpharScheme("div(phir," + alpha1.name() + ')');
const surfaceScalarField& phi = this->phi();
const surfaceScalarField& phi1 = phase1_.phi();
const surfaceScalarField& phi2 = phase2_.phi();
......@@ -236,9 +235,7 @@ void Foam::twoPhaseSystem::solve()
}
alpha1.correctBoundaryConditions();
surfaceScalarField alpha1f(fvc::interpolate(max(alpha1, scalar(0))));
surfaceScalarField phic("phic", phi);
surfaceScalarField phir("phir", phi1 - phi2);
tmp<surfaceScalarField> alphaDbyA;
......@@ -279,7 +276,7 @@ void Foam::twoPhaseSystem::solve()
),
// Divergence term is handled explicitly to be
// consistent with the explicit transport solution
fvc::div(phi)*min(alpha1, scalar(1))
fvc::div(phi_)*min(alpha1, scalar(1))
);
if (tdgdt.valid())
......@@ -300,11 +297,11 @@ void Foam::twoPhaseSystem::solve()
}
}
surfaceScalarField alphaPhic1
surfaceScalarField alphaPhi1
(
fvc::flux
(
phic,
phi_,
alpha1,
alphaScheme
)
......@@ -316,28 +313,7 @@ void Foam::twoPhaseSystem::solve()
)
);
surfaceScalarField::Boundary& alphaPhic1Bf =
alphaPhic1.boundaryFieldRef();
// Ensure that the flux at inflow BCs is preserved
forAll(alphaPhic1Bf, patchi)
{
fvsPatchScalarField& alphaPhic1p = alphaPhic1Bf[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];
}
}
}
}
phase1_.correctInflowOutflow(alphaPhi1);
if (nAlphaSubCycles > 1)
{
......@@ -355,14 +331,14 @@ void Foam::twoPhaseSystem::solve()
!(++alphaSubCycle).end();
)
{
surfaceScalarField alphaPhic10(alphaPhic1);
surfaceScalarField alphaPhi10(alphaPhi1);
MULES::explicitSolve
(
geometricOneField(),
alpha1,
phi,
alphaPhic10,
phi_,
alphaPhi10,
(alphaSubCycle.index()*Sp)(),
(Su - (alphaSubCycle.index() - 1)*Sp*alpha1)(),
phase1_.alphaMax(),
......@@ -371,11 +347,11 @@ void Foam::twoPhaseSystem::solve()
if (alphaSubCycle.index() == 1)
{
phase1_.alphaPhi() = alphaPhic10;
phase1_.alphaPhi() = alphaPhi10;
}
else
{
phase1_.alphaPhi() += alphaPhic10;
phase1_.alphaPhi() += alphaPhi10;
}
}
......@@ -387,15 +363,15 @@ void Foam::twoPhaseSystem::solve()
(
geometricOneField(),
alpha1,
phi,
alphaPhic1,
phi_,
alphaPhi1,
Sp,
Su,
phase1_.alphaMax(),
0
);
phase1_.alphaPhi() = alphaPhic1;
phase1_.alphaPhi() = alphaPhi1;
}
if (alphaDbyA.valid())
......@@ -415,8 +391,8 @@ void Foam::twoPhaseSystem::solve()
phase1_.alphaRhoPhi() =
fvc::interpolate(phase1_.rho())*phase1_.alphaPhi();
phase2_.alphaPhi() = phi - phase1_.alphaPhi();
alpha2 = scalar(1) - alpha1;
phase2_.alphaPhi() = phi_ - phase1_.alphaPhi();
phase2_.correctInflowOutflow(phase2_.alphaPhi());
phase2_.alphaRhoPhi() =
fvc::interpolate(phase2_.rho())*phase2_.alphaPhi();
......@@ -425,6 +401,13 @@ void Foam::twoPhaseSystem::solve()
<< " Min(alpha1) = " << min(alpha1).value()
<< " Max(alpha1) = " << max(alpha1).value()
<< endl;
// Ensure the phase-fractions are bounded
alpha1.max(0);
alpha1.min(1);
// Update the phase-fraction of the other phase
alpha2 = scalar(1) - alpha1;
}
}
......
......@@ -2,7 +2,7 @@
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | Copyright (C) 2011-2016 OpenFOAM Foundation
\\ / A nd | Copyright (C) 2011-2017 OpenFOAM Foundation
\\/ M anipulation |
-------------------------------------------------------------------------------
License
......@@ -248,27 +248,19 @@ bool Foam::phaseModel::read(const dictionary& phaseProperties)
}
void Foam::phaseModel::correctInflowFlux(surfaceScalarField& alphaPhi) const
void Foam::phaseModel::correctInflowOutflow(surfaceScalarField& alphaPhi) const
{
surfaceScalarField::Boundary& alphaPhiBf = alphaPhi.boundaryFieldRef();
const volScalarField::Boundary& alphaBf = boundaryField();
const surfaceScalarField::Boundary& phiBf = phi().boundaryField();
// Ensure that the flux at inflow BCs is preserved
forAll(alphaPhiBf, patchi)
{
fvsPatchScalarField& alphaPhip = alphaPhiBf[patchi];
if (!alphaPhip.coupled())
{
const scalarField& phip = phi().boundaryField()[patchi];
const scalarField& alphap = boundaryField()[patchi];
forAll(alphaPhip, facei)
{
if (phip[facei] < SMALL)