setDeltaT.H

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/*---------------------------------------------------------------------------*\
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  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
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    Copyright (C) 2017 OpenCFD Ltd.
-------------------------------------------------------------------------------
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.
 
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    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/>.
 
Global
    setDeltaT
 
Description
    Reset the timestep to maintain a constant maximum courant Number.
    Reduction of time-step is immediate, but increase is damped to avoid
    unstable oscillations.
 
\*---------------------------------------------------------------------------*/
 
if (adjustTimeStep)
{
    scalar maxDeltaTFact =
        Foam::min
        (
            maxCo/(CoNum + SMALL),
            Foam::min
            (
                maxAlphaCo/(alphaCoNum + SMALL),
                Foam::min
                (
                    maxAlphaDdt/(ddtAlphaNum + SMALL),
                    maxDi/(DiNum + SMALL)
                )
            )
        );
 
    const scalar deltaTFact =
        Foam::min(Foam::min(maxDeltaTFact, 1.0 + 0.1*maxDeltaTFact), 1.2);
 
    runTime.setDeltaT
    (
        Foam::min
        (
            deltaTFact*runTime.deltaTValue(),
            maxDeltaT
        )
    );
 
    Info<< "deltaT = " <<  runTime.deltaTValue() << endl;
}
 
 
// ************************************************************************* //