1 /*---------------------------------------------------------------------------*\
3 \\ / F ield | OpenFOAM: The Open Source CFD Toolbox
5 \\ / A nd | Copyright (C) 1991-2008 OpenCFD Ltd.
7 -------------------------------------------------------------------------------
9 This file is part of OpenFOAM.
11 OpenFOAM is free software; you can redistribute it and/or modify it
12 under the terms of the GNU General Public License as published by the
13 Free Software Foundation; either version 2 of the License, or (at your
14 option) any later version.
16 OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
17 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
18 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
21 You should have received a copy of the GNU General Public License
22 along with OpenFOAM; if not, write to the Free Software Foundation,
23 Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
29 Calculates and writes the second invariant of the velocity gradient tensor.
30 The -noWrite option just outputs the max/min values without writing
33 \*---------------------------------------------------------------------------*/
38 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
40 void Foam::calc(const argList& args, const Time& runTime, const fvMesh& mesh)
42 bool writeResults = !args.options().found("noWrite");
52 if (Uheader.headerOk())
54 Info<< " Reading U" << endl;
55 volVectorField U(Uheader, mesh);
56 volTensorField gradU = fvc::grad(U);
68 0.5*(sqr(tr(gradU)) - tr(((gradU)&(gradU))))
72 // This is a second way of calculating Q, that delivers results
73 // very close, but not identical to the first approach.
75 volSymmTensorField S = symm(gradU); // symmetric part of tensor
76 volTensorField W = skew(gradU); // anti-symmetric part
78 volScalarField SS = S&&S;
79 volScalarField WW = W&&W;
95 Info<< "mag(Q) max/min : "
96 << max(Q).value() << " "
97 << min(Q).value() << endl;
106 Info<< " No U" << endl;
110 // ************************************************************************* //