libfreefoam-dev 0.1.0+dfsg-1build1 / usr / include / freefoam / incompressibleRASModels / kOmegaSST.H

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License
    This file is part of OpenFOAM.

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    the Free Software Foundation, either version 3 of the License, or
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Class
    Foam::incompressible::RASModels::kOmegaSST

Description
    Implementation of the k-omega-SST turbulence model for incompressible
    flows.

    Turbulence model described in:
    @verbatim
        Menter, F., Esch, T.
        "Elements of Industrial Heat Transfer Prediction"
        16th Brazilian Congress of Mechanical Engineering (COBEM),
        Nov. 2001
    @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
    manner.  The paper suggests that sigma is blended but this would not be
    consistent with the blending of the k-epsilon and k-omega models.

    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
        kOmegaSSTCoeffs
        {
            alphaK1     0.85034;
            alphaK2     1.0;
            alphaOmega1 0.5;
            alphaOmega2 0.85616;
            beta1       0.075;
            beta2       0.0828;
            betaStar    0.09;
            gamma1      0.5532;
            gamma2      0.4403;
            a1          0.31;
            c1          10.0;
        }
    @endverbatim

SourceFiles
    kOmegaSST.C

\*---------------------------------------------------------------------------*/

#ifndef kOmegaSST_H
#define kOmegaSST_H

#include <incompressibleRASModels/RASModel.H>
#include <finiteVolume/wallDist.H>

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

namespace Foam
{
namespace incompressible
{
namespace RASModels
{

/*---------------------------------------------------------------------------*\
                           Class kOmega Declaration
\*---------------------------------------------------------------------------*/

class kOmegaSST
:
    public RASModel
{
    // Private data

        // Model coefficients
            dimensionedScalar alphaK1_;
            dimensionedScalar alphaK2_;

            dimensionedScalar alphaOmega1_;
            dimensionedScalar alphaOmega2_;

            dimensionedScalar gamma1_;
            dimensionedScalar gamma2_;

            dimensionedScalar beta1_;
            dimensionedScalar beta2_;

            dimensionedScalar betaStar_;

            dimensionedScalar a1_;
            dimensionedScalar c1_;

        //- Wall distance field
        //  Note: different to wall distance in parent RASModel
        wallDist y_;

        // Fields

            volScalarField k_;
            volScalarField omega_;
            volScalarField nut_;


    // Private member functions

        tmp<volScalarField> F1(const volScalarField& CDkOmega) const;
        tmp<volScalarField> F2() const;

        tmp<volScalarField> blend
        (
            const volScalarField& F1,
            const dimensionedScalar& psi1,
            const dimensionedScalar& psi2
        ) const
        {
            return F1*(psi1 - psi2) + psi2;
        }

        tmp<volScalarField> alphaK
        (
            const volScalarField& F1
        ) const
        {
            return blend(F1, alphaK1_, alphaK2_);
        }

        tmp<volScalarField> alphaOmega
        (
            const volScalarField& F1
        ) const
        {
            return blend(F1, alphaOmega1_, alphaOmega2_);
        }

        tmp<volScalarField> beta
        (
            const volScalarField& F1
        ) const
        {
            return blend(F1, beta1_, beta2_);
        }

        tmp<volScalarField> gamma
        (
            const volScalarField& F1
        ) const
        {
            return blend(F1, gamma1_, gamma2_);
        }


public:

    //- Runtime type information
    TypeName("kOmegaSST");


    // Constructors

        //- Construct from components
        kOmegaSST
        (
            const volVectorField& U,
            const surfaceScalarField& phi,
            transportModel& transport
        );


    //- Destructor
    virtual ~kOmegaSST()
    {}


    // Member Functions

        //- Return the turbulence viscosity
        virtual tmp<volScalarField> nut() const
        {
            return nut_;
        }

        //- Return the effective diffusivity for k
        tmp<volScalarField> DkEff(const volScalarField& F1) const
        {
            return tmp<volScalarField>
            (
                new volScalarField("DkEff", alphaK(F1)*nut_ + nu())
            );
        }

        //- Return the effective diffusivity for omega
        tmp<volScalarField> DomegaEff(const volScalarField& F1) const
        {
            return tmp<volScalarField>
            (
                new volScalarField("DomegaEff", alphaOmega(F1)*nut_ + nu())
            );
        }

        //- Return the turbulence kinetic energy
        virtual tmp<volScalarField> k() const
        {
            return k_;
        }

        //- Return the turbulence specific dissipation rate
        virtual tmp<volScalarField> omega() const
        {
            return omega_;
        }

        //- Return the turbulence kinetic energy dissipation rate
        virtual tmp<volScalarField> epsilon() const
        {
            return tmp<volScalarField>
            (
                new volScalarField
                (
                    IOobject
                    (
                        "epsilon",
                        mesh_.time().timeName(),
                        mesh_
                    ),
                    betaStar_*k_*omega_,
                    omega_.boundaryField().types()
                )
            );
        }

        //- Return the Reynolds stress tensor
        virtual tmp<volSymmTensorField> R() const;

        //- Return the effective stress tensor including the laminar stress
        virtual tmp<volSymmTensorField> devReff() const;

        //- Return the source term for the momentum equation
        virtual tmp<fvVectorMatrix> divDevReff(volVectorField& U) const;

        //- Solve the turbulence equations and correct the turbulence viscosity
        virtual void correct();

        //- Read RASProperties dictionary
        virtual bool read();
};


// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

} // End namespace RASModels
} // namespace incompressible
} // End namespace Foam

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

#endif

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