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Improved linearisation of coupling. Robert Keser

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This commit is contained in:
Hrvoje Jasak 2015-11-15 15:13:26 +00:00
parent da0a2f2a8a
commit d0ed6aa8ad
2 changed files with 166 additions and 59 deletions
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176
src/turbulenceModels/incompressible/RAS/coupledKOmegaSST/coupledKOmegaSST.C
View file

@ -86,6 +86,31 @@ tmp<volScalarField> coupledKOmegaSST::F2() const
}
tmp<volScalarField> coupledKOmegaSST::F3() const
{
tmp<volScalarField> arg3 = min
(
150*nu()/(omega_*sqr(y_)),
scalar(10)
);
return 1 - tanh(pow4(arg3));
}
tmp<volScalarField> coupledKOmegaSST::F23() const
{
tmp<volScalarField> f23(F2());
if (F3_)
{
f23() *= F3();
}
return f23;
}
// * * * * * * * * * * * * * * * * Constructors * * * * * * * * * * * * * * //
coupledKOmegaSST::coupledKOmegaSST
@ -99,16 +124,16 @@ coupledKOmegaSST::coupledKOmegaSST
alphaK1_
(
dimensioned<scalar>::lookupOrAddToDict
dimensionedScalar::lookupOrAddToDict
(
"alphaK1",
coeffDict_,
0.85034
0.85
)
),
alphaK2_
(
dimensioned<scalar>::lookupOrAddToDict
dimensionedScalar::lookupOrAddToDict
(
"alphaK2",
coeffDict_,
@ -117,7 +142,7 @@ coupledKOmegaSST::coupledKOmegaSST
),
alphaOmega1_
(
dimensioned<scalar>::lookupOrAddToDict
dimensionedScalar::lookupOrAddToDict
(
"alphaOmega1",
coeffDict_,
@ -126,34 +151,34 @@ coupledKOmegaSST::coupledKOmegaSST
),
alphaOmega2_
(
dimensioned<scalar>::lookupOrAddToDict
dimensionedScalar::lookupOrAddToDict
(
"alphaOmega2",
coeffDict_,
0.85616
0.856
)
),
gamma1_
(
dimensioned<scalar>::lookupOrAddToDict
dimensionedScalar::lookupOrAddToDict
(
"gamma1",
coeffDict_,
0.5532
5.0/9.0
)
),
gamma2_
(
dimensioned<scalar>::lookupOrAddToDict
dimensionedScalar::lookupOrAddToDict
(
"gamma2",
coeffDict_,
0.4403
0.44
)
),
beta1_
(
dimensioned<scalar>::lookupOrAddToDict
dimensionedScalar::lookupOrAddToDict
(
"beta1",
coeffDict_,
@ -162,7 +187,7 @@ coupledKOmegaSST::coupledKOmegaSST
),
beta2_
(
dimensioned<scalar>::lookupOrAddToDict
dimensionedScalar::lookupOrAddToDict
(
"beta2",
coeffDict_,
@ -171,7 +196,7 @@ coupledKOmegaSST::coupledKOmegaSST
),
betaStar_
(
dimensioned<scalar>::lookupOrAddToDict
dimensionedScalar::lookupOrAddToDict
(
"betaStar",
coeffDict_,
@ -180,22 +205,40 @@ coupledKOmegaSST::coupledKOmegaSST
),
a1_
(
dimensioned<scalar>::lookupOrAddToDict
dimensionedScalar::lookupOrAddToDict
(
"a1",
coeffDict_,
0.31
)
),
b1_
(
dimensionedScalar::lookupOrAddToDict
(
"b1",
coeffDict_,
1.0
)
),
c1_
(
dimensioned<scalar>::lookupOrAddToDict
dimensionedScalar::lookupOrAddToDict
(
"c1",
coeffDict_,
10.0
)
),
F3_
(
Switch::lookupOrAddToDict
(
"F3",
coeffDict_,
false
)
),
y_(mesh_),
@ -249,9 +292,18 @@ coupledKOmegaSST::coupledKOmegaSST
dimensionedVector2("zero", dimless, vector2::zero)
)
{
bound(k_, k0_);
bound(omega_, omega0_);
nut_ = a1_*k_/max(a1_*omega_, F2()*sqrt(2.0)*mag(symm(fvc::grad(U_))));
nut_ =
(
a1_*k_/
max
(
a1_*omega_,
b1_*F23()*sqrt(2.0)*mag(symm(fvc::grad(U_)))
)
);
nut_.correctBoundaryConditions();
printCoeffs();
@ -325,7 +377,9 @@ bool coupledKOmegaSST::read()
beta2_.readIfPresent(coeffDict());
betaStar_.readIfPresent(coeffDict());
a1_.readIfPresent(coeffDict());
b1_.readIfPresent(coeffDict());
c1_.readIfPresent(coeffDict());
F3_.readIfPresent("F3", coeffDict());
return true;
}
@ -358,8 +412,8 @@ void coupledKOmegaSST::correct()
y_.correct();
}
volScalarField S2 = magSqr(symm(fvc::grad(U_)));
volScalarField G("RASModel::G", nut_*2*S2);
const volScalarField S2(2*magSqr(symm(fvc::grad(U_))));
volScalarField G("RASModel::G", nut_*S2);
// Make coupled matrix
fvBlockMatrix<vector2> kOmegaEqn(kOmega_);
@ -367,12 +421,17 @@ void coupledKOmegaSST::correct()
// Update omega and G at the wall
omega_.boundaryField().updateCoeffs();
volScalarField CDkOmega =
(2*alphaOmega2_)*(fvc::grad(k_) & fvc::grad(omega_))/omega_;
const volScalarField CDkOmega
(
(2*alphaOmega2_)*(fvc::grad(k_) & fvc::grad(omega_))/omega_
);
volScalarField F1 = this->F1(CDkOmega);
const volScalarField F1(this->F1(CDkOmega));
Info<< "Coupled k-omega" << endl;
// Record coupling equations when omega is set. Same equations
// will be eliminated from k coupling as well due to wall functions
// HJ, 13/Nov/2015
labelList eliminated;
// Turbulent frequency equation
{
@ -382,14 +441,20 @@ void coupledKOmegaSST::correct()
+ fvm::div(phi_, omega_)
+ fvm::SuSp(-fvc::div(phi_), omega_)
- fvm::laplacian(DomegaEff(F1), omega_)
+ fvm::SuSp
==
gamma(F1)
*min
(
beta(F1)*omega_
+ (F1 - scalar(1))*CDkOmega/omega_,
S2,
(c1_/a1_)*betaStar_*omega_*max(a1_*omega_, b1_*F23()*sqrt(S2))
)
- fvm::Sp(2*beta(F1)*omega_, omega_)
+ beta(F1)*sqr(omega_)
- fvm::SuSp
(
(F1 - scalar(1))*CDkOmega/omega_,
omega_
)
==
gamma(F1)*2*S2
);
omegaEqn.relax();
@ -398,24 +463,26 @@ void coupledKOmegaSST::correct()
kOmegaEqn.insertEquation(1, omegaEqn);
// Add coupling term
volScalarField coupling
volScalarField couplingOmega
(
"coupling",
-gamma(F1)*2*S2/k_
"couplingOmega",
-beta(F1)*sqr(omega_)/k_
);
scalarField& couplingIn = coupling.internalField();
scalarField& couplingOmegaIn = couplingOmega.internalField();
// Eliminate coupling in wall function cells
labelList eliminated = omegaEqn.eliminatedEqns().toc();
// Collect cell indices where wall functions are active from the
// omega wall functions
eliminated = omegaEqn.eliminatedEqns().toc();
// Eliminate coupling in wall function cells for omega
forAll (eliminated, cellI)
{
couplingIn[eliminated[cellI]] *= 0;
couplingOmegaIn[eliminated[cellI]] *= 0;
}
// Insert coupling
kOmegaEqn.insertEquationCoupling(1, 0, coupling);
}
kOmegaEqn.insertEquationCoupling(1, 0, couplingOmega);
}
// Turbulent kinetic energy equation
{
@ -425,17 +492,32 @@ void coupledKOmegaSST::correct()
+ fvm::div(phi_, k_)
+ fvm::SuSp(-fvc::div(phi_), k_)
- fvm::laplacian(DkEff(F1), k_)
+ fvm::SuSp
(
betaStar_*omega_
- min(G/k_, c1_*betaStar_*omega_),
k_
)
==
min(G, c1_*betaStar_*k_*omega_)
- fvm::Sp(betaStar_*omega_, k_)
);
kEqn.relax();
kEqn.completeAssembly();
kOmegaEqn.insertEquation(0, kEqn);
// Add coupling term
volScalarField couplingK
(
"couplingK",
betaStar_*k_
);
scalarField& couplingKIn = couplingK.internalField();
// Eliminate coupling in wall function cells for k
forAll (eliminated, cellI)
{
couplingKIn[eliminated[cellI]] *= 0;
}
// Insert coupling
// kOmegaEqn.insertEquationCoupling(0, 1, couplingK);
}
// Update source coupling: coupling terms eliminated from source
@ -447,14 +529,16 @@ void coupledKOmegaSST::correct()
kOmegaEqn.retrieveSolution(0, k_.internalField());
kOmegaEqn.retrieveSolution(1, omega_.internalField());
k_.correctBoundaryConditions();
omega_.correctBoundaryConditions();
bound(k_, k0_);
bound(omega_, omega0_);
k_.correctBoundaryConditions();
omega_.correctBoundaryConditions();
// Re-calculate viscosity
nut_ = a1_*k_/max(a1_*omega_, F2()*sqrt(2*S2));
// Fixed sqrt(2) error. HJ, 10/Jun/2015
nut_ = a1_*k_/max(a1_*omega_, b1_*F23()*sqrt(S2));
nut_ = min(nut_, nuRatio()*nu());
nut_.correctBoundaryConditions();
}

49
src/turbulenceModels/incompressible/RAS/coupledKOmegaSST/coupledKOmegaSST.H
View file

@ -33,9 +33,32 @@ Description
Menter, F., Esch, T.
"Elements of Industrial Heat Transfer Prediction"
16th Brazilian Congress of Mechanical Engineering (COBEM),
Nov. 2001
Nov. 2001.
@endverbatim
with updated coefficients from
@verbatim
Menter, F. R., Kuntz, M., and Langtry, R.,
"Ten Years of Industrial Experience with the SST Turbulence Model",
Turbulence, Heat and Mass Transfer 4, 2003,
pp. 625 - 632.
@endverbatim
but with the consistent production terms from the 2001 paper as form in the
2003 paper is a typo, see
@verbatim
http://turbmodels.larc.nasa.gov/sst.html
@endverbatim
and the addition of the optional F3 term for rough walls from
\verbatim
Hellsten, A.
"Some Improvements in Menter’s k-omega-SST turbulence model"
29th AIAA Fluid Dynamics Conference,
AIAA-98-2554,
June 1998.
\endverbatim
Note that this implementation is written in terms of alpha diffusion
coefficients rather than the more traditional sigma (alpha = 1/sigma) so
that the blending can be applied to all coefficuients in a consistent
@ -45,13 +68,6 @@ Description
Also note that the error in the last term of equation (2) relating to
sigma has been corrected.
Wall-functions are applied in this implementation by using equations (14)
to specify the near-wall omega as appropriate.
The blending functions (15) and (16) are not currently used because of the
uncertainty in their origin, range of applicability and that is y+ becomes
sufficiently small blending u_tau in this manner clearly becomes nonsense.
The default model coefficients correspond to the following:
@verbatim
coupledKOmegaSSTCoeffs
@ -63,14 +79,17 @@ Description
beta1 0.075;
beta2 0.0828;
betaStar 0.09;
gamma1 0.5532;
gamma2 0.4403;
gamma1 5/9;
gamma2 0.44;
a1 0.31;
b1 1.0;
c1 10.0;
F3 no;
}
@endverbatim
Author
Robert Keser, FMENA. All rights reserved.
Hrvoje Jasak, Wikki Ltd. All rights reserved.
SourceFiles
@ -119,8 +138,11 @@ class coupledKOmegaSST
dimensionedScalar betaStar_;
dimensionedScalar a1_;
dimensionedScalar b1_;
dimensionedScalar c1_;
Switch F3_;
//- Wall distance field
// Note: different to wall distance in parent RASModel
@ -141,6 +163,8 @@ class coupledKOmegaSST
tmp<volScalarField> F1(const volScalarField& CDkOmega) const;
tmp<volScalarField> F2() const;
tmp<volScalarField> F3() const;
tmp<volScalarField> F23() const;
tmp<volScalarField> blend
(
@ -203,9 +227,8 @@ public:
//- Destructor
virtual ~coupledKOmegaSST()
{}
virtual ~coupledKOmegaSST()
{}
// Member Functions