basic.H

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Class
    Foam::PDRDragModels::basic
 
Description
    Basic sub-grid obstacle drag model.
    Details supplied by J Puttock 2/7/06.
 
    <b> Sub-grid drag term </b>
 
    The resistance term (force per unit of volume) is given by:
 
    \f[
        R = -\frac{1}{2} \rho \vert \dwea{\vec{U}} \vert \dwea{\vec{U}}.D
    \f]
 
    where:
 
        \f$ D \f$ is the tensor field "CR" in \f$ m^{-1} \f$
 
        This is term is treated implicitly in UEqn.H
 
    <b> Sub-grid turbulence generation </b>
 
    The turbulence source term \f$ G_{R} \f$ occurring in the
    \f$ \kappa-\epsilon \f$ equations for the generation of turbulence due
    to interaction with unresolved obstacles :
 
    \f$ G_{R} = C_{s}\beta_{\nu}
    \mu_{eff} A_{w}^{2}(\dwea{\vec{U}}-\dwea{\vec{U}_{s}})^2 + \frac{1}{2}
    \rho \vert \dwea{\vec{U}} \vert \dwea{\vec{U}}.T.\dwea{\vec{U}} \f$
 
    where:
 
        \f$ C_{s} \f$ = 1
 
        \f$ \beta_{\nu} \f$ is the volume porosity (file "betav").
 
        \f$ \mu_{eff} \f$ is the effective viscosity.
 
        \f$ A_{w}^{2}\f$ is the obstacle surface area per unit of volume
        (file "Aw").
 
        \f$ \dwea{\vec{U}_{s}} \f$ is the slip velocity and is considered
        \f$ \frac{1}{2}. \dwea{\vec{U}} \f$.
 
        \f$ T \f$ is a tensor in the file CT.
 
    The term \f$ G_{R} \f$ is treated explicitly in the \f$ \kappa-\epsilon
    \f$ Eqs in the \link PDRkEpsilon.C \endlink file.
 
 
SourceFiles
    basic.C
 
\*---------------------------------------------------------------------------*/
 
#ifndef basic_H
#define basic_H
 
#include "PDRDragModel.H"
#include "XiEqModel.H"
 
 
namespace Foam
{
namespace PDRDragModels
{
 
/*---------------------------------------------------------------------------*\
                          Class basic Declaration
\*---------------------------------------------------------------------------*/
 
class basic
:
    public PDRDragModel
{
    // Private data
 
        dimensionedScalar Csu;
        dimensionedScalar Csk;
 
        volScalarField Aw_;
        volSymmTensorField CR_;
 
 
    // Private Member Functions
 
        //- No copy construct
        basic(const basic&) = delete;
 
        //- No copy assignment
        void operator=(const basic&) = delete;
 
 
public:
 
    //- Runtime type information
    TypeName("basic");
 
 
    // Constructors
 
        //- Construct from components
        basic
        (
            const dictionary& PDRProperties,
            const compressible::RASModel& turbulence,
            const volScalarField& rho,
            const volVectorField& U,
            const surfaceScalarField& phi
        );
 
 
    //- Destructor
    virtual ~basic();
 
 
    // Member Functions
 
        //- Return the momentum drag coefficient
        virtual tmp<volSymmTensorField> Dcu() const;
 
        //- Return the momentum drag turbulence generation rate
        virtual tmp<volScalarField> Gk() const;
 
        //- Update properties from given dictionary
        virtual bool read(const dictionary& PDRProperties);
 
        //- Write fields
        void writeFields() const;
};
 
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
} // End namespace PDRDragModels
} // End namespace Foam
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
#endif
 
// ************************************************************************* //