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
167 lines
4.4 KiB
C++
167 lines
4.4 KiB
C++
/*---------------------------------------------------------------------------*\
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========= |
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\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
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\\ / O peration | Website: https://openfoam.org
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\\ / A nd | Copyright (C) 2011-2022 OpenFOAM Foundation
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\\/ M anipulation |
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-------------------------------------------------------------------------------
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License
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This file is part of OpenFOAM.
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OpenFOAM is free software: you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License
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along with OpenFOAM. If not, see <http://www.gnu.org/licenses/>.
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Class
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Foam::PDRDragModels::basic
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Description
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Basic sub-grid obstacle drag model.
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Details supplied by J Puttock 2/7/06.
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<b> Sub-grid drag term </b>
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The resistance term (force per unit of volume) is given by:
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\f[
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R = -\frac{1}{2} \rho \vert \dwea{\vec{U}} \vert \dwea{\vec{U}}.D
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\f]
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where:
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\f$ D \f$ is the tensor field "CR" in \f$ m^{-1} \f$
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This is term is treated implicitly in UEqn.H
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<b> Sub-grid turbulence generation </b>
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The turbulence source term \f$ G_{R} \f$ occurring in the
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\f$ \kappa-\epsilon \f$ equations for the generation of turbulence due
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to interaction with unresolved obstacles :
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\f$ G_{R} = C_{s}\beta_{\nu}
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\mu_{eff} A_{w}^{2}(\dwea{\vec{U}}-\dwea{\vec{U}_{s}})^2 + \frac{1}{2}
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\rho \vert \dwea{\vec{U}} \vert \dwea{\vec{U}}.T.\dwea{\vec{U}} \f$
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where:
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\f$ C_{s} \f$ = 1
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\f$ \beta_{\nu} \f$ is the volume porosity (file "betav").
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\f$ \mu_{eff} \f$ is the effective viscosity.
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\f$ A_{w}^{2}\f$ is the obstacle surface area per unit of volume
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(file "Aw").
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\f$ \dwea{\vec{U}_{s}} \f$ is the slip velocity and is considered
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\f$ \frac{1}{2}. \dwea{\vec{U}} \f$.
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\f$ T \f$ is a tensor in the file CT.
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The term \f$ G_{R} \f$ is treated explicitly in the \f$ \kappa-\epsilon
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\f$ Eqs in the \link PDRkEpsilon.C \endlink file.
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SourceFiles
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basic.C
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\*---------------------------------------------------------------------------*/
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#ifndef basic_H
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#define basic_H
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#include "PDRDragModel.H"
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#include "XiEqModel.H"
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namespace Foam
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{
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namespace PDRDragModels
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{
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/*---------------------------------------------------------------------------*\
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Class basic Declaration
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\*---------------------------------------------------------------------------*/
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class basic
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:
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public PDRDragModel
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{
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// Private Data
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dimensionedScalar Csu;
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dimensionedScalar Csk;
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volScalarField Aw_;
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volSymmTensorField CR_;
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public:
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//- Runtime type information
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TypeName("basic");
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// Constructors
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//- Construct from components
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basic
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(
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const dictionary& PDRProperties,
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const compressible::RASModel& turbulence,
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const volScalarField& rho,
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const volVectorField& U,
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const surfaceScalarField& phi
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);
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//- Disallow default bitwise copy construction
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basic(const basic&);
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//- Destructor
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virtual ~basic();
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// Member Functions
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//- Return the momentum drag coefficient
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virtual tmp<volSymmTensorField> Dcu() const;
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//- Return the momentum drag turbulence generation rate
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virtual tmp<volScalarField> Gk() const;
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//- Update properties from given dictionary
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virtual bool read(const dictionary& PDRProperties);
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//- Write fields
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void writeFields() const;
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// Member Operators
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//- Disallow default bitwise assignment
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void operator=(const basic&) = delete;
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};
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// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
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} // End namespace PDRDragModels
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} // End namespace Foam
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// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
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#endif
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// ************************************************************************* //
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