setDeltaT.H

Go to the documentation of this file.

/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     |
    \\  /    A nd           | www.openfoam.com
     \\/     M anipulation  |
-------------------------------------------------------------------------------
    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.
 
    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    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 =
        min
        (
            maxCo/(CoNum + SMALL),
            min
            (
                maxAlphaCo/(alphaCoNum + SMALL),
                min
                (
                    maxAlphaDdt/(ddtAlphaNum + SMALL),
                    maxDi/(DiNum + SMALL)
                )
            )
        );
 
    scalar deltaTFact = min(min(maxDeltaTFact, 1.0 + 0.1*maxDeltaTFact), 1.2);
 
    runTime.setDeltaT
    (
        min
        (
            deltaTFact*runTime.deltaTValue(),
            maxDeltaT
        )
    );
    Info<< "deltaT = " <<  runTime.deltaTValue() << endl;
}
 
 
// ************************************************************************* //