Files
OpenFOAM-12/applications/solvers/combustion/PDRFoam/PDRModels/dragModels/basic/basic.H
Henry Weller b7ea5fcc29 solvers::XiFluid: New solver module for compressible premixed/partially-premixed combustion
executed with foamRun for single region simulations of foamMultiRun for
multi-region simulations.  Replaces XiFoam and all the corresponding
tutorials have been updated and moved to tutorials/modules/XiFluid.

Class
    Foam::solvers::XiFluid

Description
    Solver module for compressible premixed/partially-premixed combustion with
    turbulence modelling.

    Combusting RANS code using the b-Xi two-equation model.
    Xi may be obtained by either the solution of the Xi transport
    equation or from an algebraic expression.  Both approaches are
    based on Gulder's flame speed correlation which has been shown
    to be appropriate by comparison with the results from the
    spectral model.

    Strain effects are encorporated directly into the Xi equation
    but not in the algebraic approximation.  Further work need to be
    done on this issue, particularly regarding the enhanced removal rate
    caused by flame compression.  Analysis using results of the spectral
    model will be required.

    For cases involving very lean Propane flames or other flames which are
    very strain-sensitive, a transport equation for the laminar flame
    speed is present.  This equation is derived using heuristic arguments
    involving the strain time scale and the strain-rate at extinction.
    the transport velocity is the same as that for the Xi equation.

    Uses the flexible PIMPLE (PISO-SIMPLE) solution for time-resolved and
    pseudo-transient and steady simulations.

    Optional fvModels and fvConstraints are provided to enhance the simulation
    in many ways including adding various sources, chemical reactions,
    combustion, Lagrangian particles, radiation, surface film etc. and
    constraining or limiting the solution.

    Reference:
    \verbatim
        Greenshields, C. J., & Weller, H. G. (2022).
        Notes on Computational Fluid Dynamics: General Principles.
        CFD Direct Ltd.: Reading, UK.
    \endverbatim

SourceFiles
    XiFluid.C

See also
    Foam::solvers::fluidSolver
    Foam::solvers::isothermalFluid
2022-12-29 23:53:33 +00:00

167 lines
4.4 KiB
C++

/*---------------------------------------------------------------------------*\
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration | Website: https://openfoam.org
\\ / A nd | Copyright (C) 2011-2022 OpenFOAM Foundation
\\/ M anipulation |
-------------------------------------------------------------------------------
License
This file is part of OpenFOAM.
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.
OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License
along with OpenFOAM. If not, see <http://www.gnu.org/licenses/>.
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_;
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
);
//- Disallow default bitwise copy construction
basic(const basic&);
//- 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;
// Member Operators
//- Disallow default bitwise assignment
void operator=(const basic&) = delete;
};
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
} // End namespace PDRDragModels
} // End namespace Foam
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
#endif
// ************************************************************************* //