HarrisCrighton.H

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/*---------------------------------------------------------------------------*\
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    Copyright (C) 2013-2016 OpenFOAM Foundation
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License
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Class
    Foam::ParticleStressModels::HarrisCrighton
 
Group
    grpLagrangianIntermediateMPPICParticleStressSubModels
 
Description
    Inter-particle stress model of Harris and Crighton
 
    The stress value takes the following form:
    \f[
        \frac{P_s \alpha^\beta}{ \mathrm{max} \left( \alpha_{pack} - \alpha ,
        \epsilon ( 1 - \alpha ) \right) }
    \f]
    Here, \f$\alpha\f$ is the volume fraction of the dispersed phase, and the
    other values are modelling constants. A small value \f$\epsilon\f$ is used
    to limit the denominator to ensure numerical stability.
 
    Reference:
    \verbatim
        "Solitons, solitary waves, and voidage disturbances in gas-fluidized
        beds"
        S Harris and D Crighton,
        Journal of Fluid Mechanics
        Volume 266, Pages 243-276, 1994
    \endverbatim
 
SourceFiles
    HarrisCrighton.C
 
\*---------------------------------------------------------------------------*/
 
#ifndef HarrisCrighton_H
#define HarrisCrighton_H
 
#include "ParticleStressModel.H"
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
namespace Foam
{
namespace ParticleStressModels
{
 
/*---------------------------------------------------------------------------*\
                        Class HarrisCrighton Declaration
\*---------------------------------------------------------------------------*/
 
class HarrisCrighton
:
    public ParticleStressModel
{
    // Private data
 
        //- Solid pressure coefficient
        scalar pSolid_;
 
        //- Exponent of the volume fraction
        scalar beta_;
 
        //- Smallest allowable difference from the packed volume fraction
        scalar eps_;
 
 
    // Private member functions
 
        //- Return the limited denominator of the radial distribution function
        tmp<Field<scalar>> denominator(const Field<scalar>& alpha) const;
 
 
public:
 
    //- Runtime type information
    TypeName("HarrisCrighton");
 
 
    //- Constructors
 
        //- Construct from components
        HarrisCrighton(const dictionary& dict);
 
        //- Construct copy
        HarrisCrighton(const HarrisCrighton& hc);
 
        //- Clone
        virtual autoPtr<ParticleStressModel> clone() const
        {
            return autoPtr<ParticleStressModel>
            (
                new HarrisCrighton(*this)
            );
        }
 
 
    //- Destructor
    virtual ~HarrisCrighton();
 
 
    //- Member Functions
 
        //- Collision stress
        tmp<Field<scalar>> tau
        (
            const Field<scalar>& alpha,
            const Field<scalar>& rho,
            const Field<scalar>& uRms
        ) const;
 
        //- Collision stress derivative w.r.t. the volume fraction
        tmp<Field<scalar>> dTaudTheta
        (
            const Field<scalar>& alpha,
            const Field<scalar>& rho,
            const Field<scalar>& uRms
        ) const;
};
 
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
} // End namespace ParticleStressModels
} // End namespace Foam
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
#endif
 
// ************************************************************************* //