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setDeltaT.H

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00001 /*---------------------------------------------------------------------------*\
00002   =========                 |
00003   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
00004    \\    /   O peration     |
00005     \\  /    A nd           | Copyright (C) 1991-2010 OpenCFD Ltd.
00006      \\/     M anipulation  |
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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
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00014     (at your option) any later version.
00015 
00016     OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
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00019     for more details.
00020 
00021     You should have received a copy of the GNU General Public License
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00023 
00024 Global
00025     setDeltaT
00026 
00027 Description
00028     Reset the timestep to maintain a constant maximum courant Number.
00029     Reduction of time-step is immediate, but increase is damped to avoid
00030     unstable oscillations.
00031 
00032 \*---------------------------------------------------------------------------*/
00033 
00034 if (adjustTimeStep)
00035 {
00036     scalar maxDeltaTFact = maxCo/(CoNum + SMALL);
00037     scalar deltaTFact = min(min(maxDeltaTFact, 1.0 + 0.1*maxDeltaTFact), 1.2);
00038 
00039     runTime.setDeltaT
00040     (
00041         min
00042         (
00043             deltaTFact*runTime.deltaT().value(),
00044             maxDeltaT
00045         )
00046     );
00047 
00048     Info<< "deltaT = " <<  runTime.deltaT().value() << endl;
00049 }
00050 
00051 // ************************ vim: set sw=4 sts=4 et: ************************ //
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