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|
/*---------------------------------------------------------------------------*\
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | Copyright (C) 2013-2016 OpenFOAM Foundation
\\/ M anipulation |
-------------------------------------------------------------------------------
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/>.
\*---------------------------------------------------------------------------*/
{
volScalarField& rDeltaT = trDeltaT.ref();
const dictionary& pimpleDict = pimple.dict();
// Maximum flow Courant number
scalar maxCo(readScalar(pimpleDict.lookup("maxCo")));
// Maximum time scale
scalar maxDeltaT(pimpleDict.lookupOrDefault<scalar>("maxDeltaT", GREAT));
// Smoothing parameter (0-1) when smoothing iterations > 0
scalar rDeltaTSmoothingCoeff
(
pimpleDict.lookupOrDefault<scalar>("rDeltaTSmoothingCoeff", 0.1)
);
// Damping coefficient (1-0)
scalar rDeltaTDampingCoeff
(
pimpleDict.lookupOrDefault<scalar>("rDeltaTDampingCoeff", 1)
);
// Maximum change in cell temperature per iteration
// (relative to previous value)
scalar alphaTemp(pimpleDict.lookupOrDefault("alphaTemp", 0.05));
Info<< "Time scales min/max:" << endl;
// Cache old reciprocal time scale field
volScalarField rDeltaT0("rDeltaT0", rDeltaT);
// Flow time scale
{
rDeltaT.ref() =
(
fvc::surfaceSum(mag(phi))()()
/((2*maxCo)*mesh.V()*rho())
);
// Limit the largest time scale
rDeltaT.max(1/maxDeltaT);
Info<< " Flow = "
<< gMin(1/rDeltaT.primitiveField()) << ", "
<< gMax(1/rDeltaT.primitiveField()) << endl;
}
// Reaction source time scale
if (alphaTemp < 1.0)
{
volScalarField::Internal rDeltaTT
(
mag(reaction->Sh())/(alphaTemp*rho*thermo.Cp()*T)
);
Info<< " Temperature = "
<< gMin(1/(rDeltaTT.field() + VSMALL)) << ", "
<< gMax(1/(rDeltaTT.field() + VSMALL)) << endl;
rDeltaT.ref() = max
(
rDeltaT(),
rDeltaTT
);
}
// Update tho boundary values of the reciprocal time-step
rDeltaT.correctBoundaryConditions();
// Spatially smooth the time scale field
if (rDeltaTSmoothingCoeff < 1.0)
{
fvc::smooth(rDeltaT, rDeltaTSmoothingCoeff);
}
// Limit rate of change of time scale
// - reduce as much as required
// - only increase at a fraction of old time scale
if
(
rDeltaTDampingCoeff < 1.0
&& runTime.timeIndex() > runTime.startTimeIndex() + 1
)
{
rDeltaT = max
(
rDeltaT,
(scalar(1.0) - rDeltaTDampingCoeff)*rDeltaT0
);
}
// Update tho boundary values of the reciprocal time-step
rDeltaT.correctBoundaryConditions();
Info<< " Overall = "
<< gMin(1/rDeltaT.primitiveField())
<< ", " << gMax(1/rDeltaT.primitiveField()) << endl;
}
// ************************************************************************* //
|
