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MomentumTransportModels::k-omega model: Improved omega bounding using nutMaxCoeff

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Omega lower limit bounding is now based on a maximum turbulence viscosity nut
rather than a minimum omega value which improves stability and robustness of
the k-omega models in case of numerical boundedness problems.

The maximum nut value is calculated by multiplying the laminar viscosity by
nutMaxCoeff which defaults to 1e5 but can be set by the user in the
momentumTransport dictionary.
This commit is contained in:
Henry Weller
2023-12-19 22:50:10 +00:00
parent b1c6ddb197
commit 195dfbe168
13 changed files with 81 additions and 74 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
applications/utilities/preProcessing/applyBoundaryLayer/applyBoundaryLayer.C
View File

@ -195,7 +195,6 @@ int main(int argc, char *argv[])
refCast<const incompressible::RASModel>(turbulence());
omega = (1 - mask)*omega + mask*ce0*sqrt(k)/(Cmu*min(y, ybl));
bound(omega, rasModel.omegaMin());
// Do not correct BC - G set by the wall-functions is not available
// omega.correctBoundaryConditions();

15
src/MomentumTransportModels/incompressible/RAS/kkLOmega/kkLOmega.C
View File

@ -492,6 +492,16 @@ kkLOmega::kkLOmega
1.17
)
),
omegaMin_
(
dimensioned<scalar>::lookupOrAddToDict
(
"omegaMin",
coeffDict_,
dimless/dimTime,
small
)
),
kt_
(
IOobject
@ -536,12 +546,13 @@ kkLOmega::kkLOmega
runTime_.name(),
mesh_
),
kt_*max(omega_, omegaMin_) + D(kl_) + D(kt_)
kt_*omega_
)
{
bound(kt_, kMin_);
bound(kl_, kMin_);
bound(omega_, omegaMin_);
epsilon_ = kt_*omega_ + D(kl_) + D(kt_);
if (type == typeName)
{
@ -751,9 +762,11 @@ void kkLOmega::correct()
solve(ktEqn);
bound(kt_, kMin_);
// Update total fluctuation kinetic energy dissipation rate
epsilon_ = kt_*omega_ + Dl + Dt;
// Re-calculate turbulent viscosity
nut_ = nuts + nutl;
nut_.correctBoundaryConditions();

3
src/MomentumTransportModels/incompressible/RAS/kkLOmega/kkLOmega.H
View File

@ -192,6 +192,9 @@ protected:
dimensionedScalar Sigmak_;
dimensionedScalar Sigmaw_;
//- Lower limit for omega
dimensionedScalar omegaMin_;
// Fields

26
src/MomentumTransportModels/momentumTransportModels/Base/kOmegaSST/kOmegaSSTBase.C
View File

@ -36,9 +36,17 @@ namespace Foam
// * * * * * * * * * * * Protected Member Functions * * * * * * * * * * * * //
template<class MomentumTransportModel, class BasicMomentumTransportModel>
void
kOmegaSST<MomentumTransportModel, BasicMomentumTransportModel>::boundOmega()
{
omega_ = max(omega_, k_/(this->nutMaxCoeff_*this->nu()));
}
template<class MomentumTransportModel, class BasicMomentumTransportModel>
tmp<volScalarField>
kOmegaSST<MomentumTransportModel, BasicMomentumTransportModel>::kOmegaSST::F1
kOmegaSST<MomentumTransportModel, BasicMomentumTransportModel>::F1
(
const volScalarField& CDkOmega
) const
@ -68,8 +76,7 @@ kOmegaSST<MomentumTransportModel, BasicMomentumTransportModel>::kOmegaSST::F1
template<class MomentumTransportModel, class BasicMomentumTransportModel>
tmp<volScalarField>
kOmegaSST<MomentumTransportModel, BasicMomentumTransportModel>::kOmegaSST::
F2() const
kOmegaSST<MomentumTransportModel, BasicMomentumTransportModel>::F2() const
{
tmp<volScalarField> arg2 = min
(
@ -86,8 +93,7 @@ F2() const
template<class MomentumTransportModel, class BasicMomentumTransportModel>
tmp<volScalarField>
kOmegaSST<MomentumTransportModel, BasicMomentumTransportModel>::kOmegaSST::
F3() const
kOmegaSST<MomentumTransportModel, BasicMomentumTransportModel>::F3() const
{
tmp<volScalarField> arg3 = min
(
@ -100,8 +106,7 @@ F3() const
template<class MomentumTransportModel, class BasicMomentumTransportModel>
tmp<volScalarField>
kOmegaSST<MomentumTransportModel, BasicMomentumTransportModel>::kOmegaSST::
F23() const
kOmegaSST<MomentumTransportModel, BasicMomentumTransportModel>::F23() const
{
tmp<volScalarField> f23(F2());
@ -127,8 +132,6 @@ void kOmegaSST<MomentumTransportModel, BasicMomentumTransportModel>::correctNut
}
// * * * * * * * * * * * * Protected Member Functions * * * * * * * * * * * //
template<class MomentumTransportModel, class BasicMomentumTransportModel>
void kOmegaSST<MomentumTransportModel, BasicMomentumTransportModel>::
correctNut()
@ -380,7 +383,7 @@ kOmegaSST<MomentumTransportModel, BasicMomentumTransportModel>::kOmegaSST
)
{
bound(k_, this->kMin_);
bound(omega_, this->omegaMin_);
boundOmega();
}
@ -493,7 +496,7 @@ void kOmegaSST<MomentumTransportModel, BasicMomentumTransportModel>::correct()
omegaEqn.ref().boundaryManipulate(omega_.boundaryFieldRef());
solve(omegaEqn);
fvConstraints.constrain(omega_);
bound(omega_, this->omegaMin_);
boundOmega();
}
// Turbulent kinetic energy equation
@ -515,6 +518,7 @@ void kOmegaSST<MomentumTransportModel, BasicMomentumTransportModel>::correct()
solve(kEqn);
fvConstraints.constrain(k_);
bound(k_, this->kMin_);
boundOmega();
correctNut(S2, F23);
}

3
src/MomentumTransportModels/momentumTransportModels/Base/kOmegaSST/kOmegaSSTBase.H
View File

@ -200,6 +200,9 @@ protected:
return blend(F1, gamma1_, gamma2_);
}
//- Bound omega
void boundOmega();
virtual void correctNut
(
const volScalarField& S2,

9
src/MomentumTransportModels/momentumTransportModels/LES/LESModel/LESModel.C
View File

@ -79,14 +79,14 @@ Foam::LESModel<BasicMomentumTransportModel>::LESModel
)
),
omegaMin_
nutMaxCoeff_
(
dimensioned<scalar>::lookupOrAddToDict
(
"omegaMin",
"nutMaxCoeff",
LESDict_,
dimless/dimTime,
small
dimless,
1e5
)
),
@ -192,6 +192,7 @@ bool Foam::LESModel<BasicMomentumTransportModel>::read()
delta_().read(LESDict_);
kMin_.readIfPresent(LESDict_);
nutMaxCoeff_.readIfPresent(LESDict_);
return true;
}

16
src/MomentumTransportModels/momentumTransportModels/LES/LESModel/LESModel.H
View File

@ -82,8 +82,8 @@ protected:
//- Lower limit of k
dimensionedScalar kMin_;
//- Lower limit for omega
dimensionedScalar omegaMin_;
//- Upper limit coefficient for nut
dimensionedScalar nutMaxCoeff_;
//- Run-time selectable generalised Newtonian viscosity model
autoPtr<laminarModels::generalisedNewtonianViscosityModel>
@ -176,18 +176,6 @@ public:
return coeffDict_;
}
//- Return the lower allowable limit for k (default: small)
const dimensionedScalar& kMin() const
{
return kMin_;
}
//- Allow kMin to be changed
dimensionedScalar& kMin()
{
return kMin_;
}
//- Access function to filter width
inline const volScalarField& delta() const
{

13
src/MomentumTransportModels/momentumTransportModels/RAS/RASModel/RASModel.C
View File

@ -79,17 +79,6 @@ Foam::RASModel<BasicMomentumTransportModel>::RASModel
)
),
omegaMin_
(
dimensioned<scalar>::lookupOrAddToDict
(
"omegaMin",
RASDict_,
dimless/dimTime,
small
)
),
nutMaxCoeff_
(
dimensioned<scalar>::lookupOrAddToDict
@ -191,7 +180,7 @@ bool Foam::RASModel<BasicMomentumTransportModel>::read()
coeffDict_ <<= RASDict_.optionalSubDict(type() + "Coeffs");
kMin_.readIfPresent(RASDict_);
omegaMin_.readIfPresent(RASDict_);
nutMaxCoeff_.readIfPresent(RASDict_);
return true;
}

27
src/MomentumTransportModels/momentumTransportModels/RAS/RASModel/RASModel.H
View File

@ -75,9 +75,6 @@ protected:
//- Lower limit of k
dimensionedScalar kMin_;
//- Lower limit for omega
dimensionedScalar omegaMin_;
//- Upper limit coefficient for nut
dimensionedScalar nutMaxCoeff_;
@ -163,30 +160,6 @@ public:
//- Read model coefficients if they have changed
virtual bool read();
//- Return the lower allowable limit for k (default: small)
const dimensionedScalar& kMin() const
{
return kMin_;
}
//- Return the lower allowable limit for omega (default: small)
const dimensionedScalar& omegaMin() const
{
return omegaMin_;
}
//- Allow kMin to be changed
dimensionedScalar& kMin()
{
return kMin_;
}
//- Allow omegaMin to be changed
dimensionedScalar& omegaMin()
{
return omegaMin_;
}
//- Const access to the coefficients dictionary
virtual const dictionary& coeffDict() const
{

12
src/MomentumTransportModels/momentumTransportModels/RAS/kOmega/kOmega.C
View File

@ -37,6 +37,13 @@ namespace RASModels
// * * * * * * * * * * * * Protected Member Functions * * * * * * * * * * * //
template<class BasicMomentumTransportModel>
void kOmega<BasicMomentumTransportModel>::boundOmega()
{
omega_ = max(omega_, k_/(this->nutMaxCoeff_*this->nu()));
}
template<class BasicMomentumTransportModel>
void kOmega<BasicMomentumTransportModel>::correctNut()
{
@ -172,7 +179,7 @@ kOmega<BasicMomentumTransportModel>::kOmega
)
{
bound(k_, this->kMin_);
bound(omega_, this->omegaMin_);
boundOmega();
if (type == typeName)
{
@ -260,7 +267,7 @@ void kOmega<BasicMomentumTransportModel>::correct()
omegaEqn.ref().boundaryManipulate(omega_.boundaryFieldRef());
solve(omegaEqn);
fvConstraints.constrain(omega_);
bound(omega_, this->omegaMin_);
boundOmega();
// Turbulent kinetic energy equation
@ -282,6 +289,7 @@ void kOmega<BasicMomentumTransportModel>::correct()
solve(kEqn);
fvConstraints.constrain(k_);
bound(k_, this->kMin_);
boundOmega();
correctNut();
}

8
src/MomentumTransportModels/momentumTransportModels/RAS/kOmega/kOmega.H
View File

@ -96,8 +96,16 @@ protected:
// Protected Member Functions
//- Bound omega
void boundOmega();
//- Correct the eddy-viscosity nut
virtual void correctNut();
//- Source term for the k equation
virtual tmp<fvScalarMatrix> kSource() const;
//- Source term for the omega equation
virtual tmp<fvScalarMatrix> omegaSource() const;

14
src/MomentumTransportModels/momentumTransportModels/RAS/kOmega2006/kOmega2006.C
View File

@ -35,6 +35,15 @@ namespace Foam
namespace RASModels
{
// * * * * * * * * * * * * Protected Member Functions * * * * * * * * * * * //
template<class BasicMomentumTransportModel>
void kOmega2006<BasicMomentumTransportModel>::boundOmega()
{
omega_ = max(omega_, k_/(this->nutMaxCoeff_*this->nu()));
}
template<class BasicMomentumTransportModel>
void kOmega2006<BasicMomentumTransportModel>::correctNut
(
@ -238,7 +247,7 @@ kOmega2006<BasicMomentumTransportModel>::kOmega2006
)
{
bound(k_, this->kMin_);
bound(omega_, this->omegaMin_);
boundOmega();
if (type == typeName)
{
@ -328,7 +337,7 @@ void kOmega2006<BasicMomentumTransportModel>::correct()
omegaEqn.ref().boundaryManipulate(omega_.boundaryFieldRef());
solve(omegaEqn);
fvConstraints.constrain(omega_);
bound(omega_, this->omegaMin_);
boundOmega();
// Turbulent kinetic energy equation
@ -350,6 +359,7 @@ void kOmega2006<BasicMomentumTransportModel>::correct()
solve(kEqn);
fvConstraints.constrain(k_);
bound(k_, this->kMin_);
boundOmega();
correctNut(gradU);
}

8
src/MomentumTransportModels/momentumTransportModels/RAS/kOmega2006/kOmega2006.H
View File

@ -111,8 +111,16 @@ protected:
// Protected Member Functions
//- Bound omega
void boundOmega();
//- Correct the eddy-viscosity nut
virtual void correctNut();
//- Source term for the k equation
virtual tmp<fvScalarMatrix> kSource() const;
//- Source term for the omega equation
virtual tmp<fvScalarMatrix> omegaSource() const;