165 lines
4.3 KiB
C++
165 lines
4.3 KiB
C++
/*---------------------------------------------------------------------------*\
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========= |
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\\ / F ield | foam-extend: Open Source CFD
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\\ / O peration |
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\\ / A nd | For copyright notice see file Copyright
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\\/ M anipulation |
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-------------------------------------------------------------------------------
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License
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This file is part of foam-extend.
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foam-extend 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 the
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Free Software Foundation, either version 3 of the License, or (at your
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option) any later version.
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foam-extend is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License 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 foam-extend. 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 Aw2_;
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volSymmTensorField CR_;
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volSymmTensorField CT_;
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// Private Member Functions
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//- Disallow copy construct
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basic(const basic&);
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//- Disallow default bitwise assignment
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void operator=(const basic&);
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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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// 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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};
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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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