127 lines
4.1 KiB
C++
127 lines
4.1 KiB
C++
/*---------------------------------------------------------------------------*\
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========= |
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\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
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\\ / O peration | Website: https://openfoam.org
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\\ / A nd | Copyright (C) 2022-2024 OpenFOAM Foundation
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\\/ M anipulation |
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-------------------------------------------------------------------------------
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License
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This file is part of OpenFOAM.
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OpenFOAM is free software: you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License
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along with OpenFOAM. If not, see <http://www.gnu.org/licenses/>.
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\*---------------------------------------------------------------------------*/
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#include "isothermalFluid.H"
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#include "fvcFlux.H"
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#include "fvcSmooth.H"
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#include "fvcSurfaceIntegrate.H"
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// * * * * * * * * * * * * * Private Member Functions * * * * * * * * * * * //
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void Foam::solvers::isothermalFluid::setRDeltaT()
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{
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const volScalarField& psi = thermo.psi();
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volScalarField& rDeltaT = trDeltaT.ref();
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const dictionary& pimpleDict = pimple.dict();
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const scalar maxCo
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(
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pimpleDict.lookupOrDefault<scalar>("maxCo", 0.8)
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);
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const scalar rDeltaTSmoothingCoeff
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(
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pimpleDict.lookupOrDefault<scalar>("rDeltaTSmoothingCoeff", 0.02)
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);
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const volScalarField rDeltaT0("rDeltaT0", rDeltaT);
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// Set the reciprocal time-step from the local Courant number
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rDeltaT.internalFieldRef() =
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fvc::surfaceSum(mag(phi))()()/((2*maxCo)*mesh.V()*rho());
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// Set the reciprocal time-step from the local acoustic Courant number
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if (pimple.transonic())
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{
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surfaceScalarField phid("phid", fvc::interpolate(psi)*fvc::flux(U));
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rDeltaT.internalFieldRef() =
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max
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(
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rDeltaT(),
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fvc::surfaceSum(mag(phid))()()/((2*maxCo)*mesh.V()*psi())
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);
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}
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// Clip to user-defined maximum and minimum time-steps
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scalar minRDeltaT = gMin(rDeltaT.primitiveField());
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if (pimpleDict.found("maxDeltaT") || minRDeltaT < rootVSmall)
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{
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const scalar clipRDeltaT = 1/pimpleDict.lookup<scalar>("maxDeltaT");
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rDeltaT.max(clipRDeltaT);
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minRDeltaT = max(minRDeltaT, clipRDeltaT);
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}
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if (pimpleDict.found("minDeltaT"))
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{
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const scalar clipRDeltaT = 1/pimpleDict.lookup<scalar>("minDeltaT");
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rDeltaT.min(clipRDeltaT);
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minRDeltaT = min(minRDeltaT, clipRDeltaT);
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}
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Info<< "Flow time scale min/max = "
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<< gMin(1/rDeltaT.primitiveField()) << ", " << 1/minRDeltaT << endl;
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// Update the boundary values of the reciprocal time-step
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rDeltaT.correctBoundaryConditions();
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if (rDeltaTSmoothingCoeff < 1.0)
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{
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fvc::smooth(rDeltaT, rDeltaTSmoothingCoeff);
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}
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Info<< "Smoothed flow time scale min/max = "
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<< gMin(1/rDeltaT.primitiveField())
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<< ", " << gMax(1/rDeltaT.primitiveField()) << endl;
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// Limit rate of change of time scale
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// - reduce as much as required
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// - only increase at a fraction of old time scale
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if
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(
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pimpleDict.found("rDeltaTDampingCoeff")
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&& runTime.timeIndex() > runTime.startTimeIndex() + 1
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)
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{
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// Damping coefficient (1-0)
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const scalar rDeltaTDampingCoeff
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(
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pimpleDict.lookup<scalar>("rDeltaTDampingCoeff")
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);
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rDeltaT =
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rDeltaT0
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*max(rDeltaT/rDeltaT0, scalar(1) - rDeltaTDampingCoeff);
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Info<< "Damped flow time scale min/max = "
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<< gMin(1/rDeltaT.primitiveField())
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<< ", " << gMax(1/rDeltaT.primitiveField()) << endl;
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}
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}
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// ************************************************************************* //
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