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/*---------------------------------------------------------------------------*\
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\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | Copyright (C) 2013 OpenFOAM Foundation
\\/ M anipulation |
-------------------------------------------------------------------------------
License
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OpenFOAM is free software: you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
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Class
Foam::ParticleStressModels::Lun
Description
Inter-particle stress model of Lun et al
The stress value takes the following form:
\f[
\left( \alpha \rho + \alpha^2 \rho (1 + e) \frac{3}{5}
\left( 1 - \left( \frac{\alpha}{\alpha_{pack}} \right)^\frac{1}{3}
\right) \right) \frac{1}{3} \sigma^2
Here, \f$\alpha\f$ is the volume fraction of the dispersed phase,
\f$\rho\f$ is the density of the dispersed phase, \f$e\f$ is a coefficient
of restitution, and \f$\sigma\f$ is the RMS velocity fluctuation.
Reference:
\verbatim
"Kinetic theories for granular flow: inelastic particles in Couette
flow and slightly inelastic particles in a general flowfield"
C Lun, S Savage, G Jeffrey, N Chepurniy
Journal of Fluid Mechanics
Volume 1, Page 223, April 2006
\endverbatim
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Lun.C
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\*---------------------------------------------------------------------------*/
#ifndef Lun_H
#define Lun_H
#include "ParticleStressModel.H"
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
namespace Foam
{
namespace ParticleStressModels
{
/*---------------------------------------------------------------------------*\
Class Lun Declaration
\*---------------------------------------------------------------------------*/
class Lun
:
public ParticleStressModel
{
// Private data
//- Coefficient of restitution
scalar e_;
//- Smallest allowable difference from the packed volume fraction
scalar eps_;
public:
//- Runtime type information
TypeName("Lun");
//- Constructors
//- Construct from components
Lun(const dictionary& dict);
//- Construct copy
Lun(const Lun& hc);
//- Clone
virtual autoPtr<ParticleStressModel> clone() const
{
return autoPtr<ParticleStressModel>
(
new Lun(*this)
);
}
//- Destructor
virtual ~Lun();
//- Member Functions
//- Collision stress
tmp<Field<scalar> > tau
(
const Field<scalar>& alpha,
const Field<scalar>& rho,
const Field<scalar>& uRms
) const;
//- Collision stress derivaive 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
// ************************************************************************* //