SpalartAllmaras.H

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License
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Class
    Foam::RASModels::SpalartAllmaras

Description
    Spalart-Allmaras one-eqn mixing-length model for incompressible and
    compressible external flows.

    Reference:
    \verbatim
        Spalart, P.R., & Allmaras, S.R. (1994).
        A one-equation turbulence model for aerodynamic flows.
        La Recherche Aerospatiale, 1, 5-21.
    \endverbatim

    The model is implemented without the trip-term and hence the ft2 term is
    not needed.

    It is necessary to limit the Stilda generation term as the model generates
    unphysical results if this term becomes negative which occurs for complex
    flow.  Several approaches have been proposed to limit Stilda but it is not
    clear which is the most appropriate.  Here the limiter proposed by Spalart
    is implemented in which Stilda is clipped at Cs*Omega with the default value
    of Cs = 0.3.

    The default model coefficients are
    \verbatim
        SpalartAllmarasCoeffs
        {
            Cb1         0.1355;
            Cb2         0.622;
            Cw2         0.3;
            Cw3         2.0;
            Cv1         7.1;
            Cs          0.3;
            sigmaNut    0.66666;
            kappa       0.41;
        }
    \endverbatim

SourceFiles
    SpalartAllmaras.C

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

#ifndef SpalartAllmaras_H
#define SpalartAllmaras_H

#include "RASModel.H"
#include "eddyViscosity.H"

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

namespace Foam
{
namespace RASModels
{

/*---------------------------------------------------------------------------*\
                      Class SpalartAllmaras Declaration
\*---------------------------------------------------------------------------*/

template<class BasicTurbulenceModel>
class SpalartAllmaras
:
    public eddyViscosity<RASModel<BasicTurbulenceModel>>
{
    // Private Member Functions

        // Disallow default bitwise copy construct and assignment
        SpalartAllmaras(const SpalartAllmaras&);
        void operator=(const SpalartAllmaras&);


protected:

    // Protected data

        // Model coefficients

            dimensionedScalar sigmaNut_;
            dimensionedScalar kappa_;

            dimensionedScalar Cb1_;
            dimensionedScalar Cb2_;
            dimensionedScalar Cw1_;
            dimensionedScalar Cw2_;
            dimensionedScalar Cw3_;
            dimensionedScalar Cv1_;
            dimensionedScalar Cs_;


        // Fields

            volScalarField nuTilda_;

            //- Wall distance
            //  Note: different to wall distance in parent RASModel
            //  which is for near-wall cells only
            const volScalarField& y_;


    // Protected Member Functions

        tmp<volScalarField> chi() const;

        tmp<volScalarField> fv1(const volScalarField& chi) const;

        tmp<volScalarField> fv2
        (
            const volScalarField& chi,
            const volScalarField& fv1
        ) const;

        tmp<volScalarField> Stilda
        (
            const volScalarField& chi,
            const volScalarField& fv1
        ) const;

        tmp<volScalarField> fw(const volScalarField& Stilda) const;

        void correctNut(const volScalarField& fv1);
        virtual void correctNut();


public:

    typedef typename BasicTurbulenceModel::alphaField alphaField;
    typedef typename BasicTurbulenceModel::rhoField rhoField;
    typedef typename BasicTurbulenceModel::transportModel transportModel;


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


    // Constructors

        //- Construct from components
        SpalartAllmaras
        (
            const alphaField& alpha,
            const rhoField& rho,
            const volVectorField& U,
            const surfaceScalarField& alphaRhoPhi,
            const surfaceScalarField& phi,
            const transportModel& transport,
            const word& propertiesName = turbulenceModel::propertiesName,
            const word& type = typeName
        );


    //- Destructor
    virtual ~SpalartAllmaras()
    {}


    // Member Functions

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

        //- Return the effective diffusivity for nuTilda
        tmp<volScalarField> DnuTildaEff() const;

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

        //- Return the turbulence kinetic energy dissipation rate
        virtual tmp<volScalarField> epsilon() const;

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


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

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

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

#ifdef NoRepository
    #include "SpalartAllmaras.C"
#endif

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

#endif

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