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Phi.H

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00001 /*---------------------------------------------------------------------------*\
00002   =========                 |
00003   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
00004    \\    /   O peration     |
00005     \\  /    A nd           | Copyright (C) 1991-2005 OpenCFD Ltd.
00006      \\/     M anipulation  |
00007 -------------------------------------------------------------------------------
00008 License
00009     This file is part of OpenFOAM.
00010 
00011     OpenFOAM is free software; you can redistribute it and/or modify it
00012     under the terms of the GNU General Public License as published by the
00013     Free Software Foundation; either version 2 of the License, or (at your
00014     option) any later version.
00015 
00016     OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
00017     ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
00018     FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
00019     for more details.
00020 
00021     You should have received a copy of the GNU General Public License
00022     along with OpenFOAM; if not, write to the Free Software Foundation,
00023     Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
00024 
00025 Class
00026     PhiLimiter
00027 
00028 Description
00029     Class with limiter function which returns the limiter for the
00030     Phi differencing scheme.
00031 
00032     Used in conjunction with the template class PhiScheme.
00033 
00034 SourceFiles
00035     Phi.C
00036 
00037 \*---------------------------------------------------------------------------*/
00038 
00039 #ifndef Phi_H
00040 #define Phi_H
00041 
00042 #include "vector.H"
00043 
00044 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
00045 
00046 namespace Foam
00047 {
00048 
00049 /*---------------------------------------------------------------------------*\
00050                            Class PhiLimiter Declaration
00051 \*---------------------------------------------------------------------------*/
00052 
00053 class PhiLimiter
00054 {
00055     scalar k_;
00056 
00057 public:
00058 
00059     PhiLimiter(Istream& is)
00060     :
00061         k_(readScalar(is))
00062     {
00063         if (k_ < 0 || k_ > 1)
00064         {
00065             FatalIOErrorIn("PhiLimiter(Istream& is)", is)
00066                 << "coefficient = " << k_
00067                 << " should be >= 0 and <= 1"
00068                 << exit(FatalIOError);
00069         }
00070     }
00071 
00072     scalar limiter
00073     (
00074         const scalar cdWeight,
00075         const scalar faceFlux,
00076         const vector& PhiP,
00077         const vector& PhiN,
00078         const vector& Sf,
00079         const scalar&
00080     ) const
00081     {
00082         scalar phiP = Sf&PhiP;
00083         scalar phiN = Sf&PhiN;
00084 
00085         scalar phiU;
00086 
00087         if (faceFlux > 0)
00088         {
00089             phiU = phiP;
00090         }
00091         else
00092         {
00093             phiU = phiN;
00094         }
00095 
00096         scalar phiCD = cdWeight*phiP + (1 - cdWeight)*phiN;
00097 
00098         // Calculate the effective limiter for the Phi interpolation
00099         scalar PLimiter =
00100             (1.0 - k_) + k_*(faceFlux - phiU)/stabilise(phiCD - phiU, SMALL);
00101 
00102         // Limit the limiter between upwind and central
00103         return max(min(PLimiter, 1.0), 0);
00104     }
00105 };
00106 
00107 
00108 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
00109 
00110 } // End namespace Foam
00111 
00112 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
00113 
00114 #endif
00115 
00116 // ************************************************************************* //
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