1 /*---------------------------------------------------------------------------* \
3 \\ / F ield | OpenFOAM: The Open Source CFD Toolbox
5 \\ / A nd | Copyright (C) 1991-2009 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.
31 The -noWrite option just outputs the max/min values without writing
34 \*---------------------------------------------------------------------------*/
39 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
41 void Foam::calc(const argList& args, const Time& runTime, const fvMesh& mesh)
43 bool writeResults = !args.optionFound("noWrite");
53 if (Uheader.headerOk())
55 Info<< " Reading U" << endl;
56 volVectorField U(Uheader, mesh);
57 volTensorField gradU = fvc::grad(U);
69 0.5*(sqr(tr(gradU)) - tr(((gradU)&(gradU))))
73 // This is a second way of calculating Q, that delivers results
74 // very close, but not identical to the first approach.
76 volSymmTensorField S = symm(gradU); // symmetric part of tensor
77 volTensorField W = skew(gradU); // anti-symmetric part
79 volScalarField SS = S&&S;
80 volScalarField WW = W&&W;
96 Info<< "mag(Q) max/min : "
97 << max(Q).value() << " "
98 << min(Q).value() << endl;
107 Info<< " No U" << endl;
110 Info<< "\nEnd\n" << endl;
114 // ************************************************************************* //