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/*---------------------------------------------------------------------------*\
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | Copyright (C) 2011-2016 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/>.
Application
momentOfInertiaTest
Description
Calculates the inertia tensor and principal axes and moments of a
test face, tetrahedron and cell.
\*---------------------------------------------------------------------------*/
#include "argList.H"
#include "Time.H"
#include "polyMesh.H"
#include "ListOps.H"
#include "face.H"
#include "tetrahedron.H"
#include "triFaceList.H"
#include "OFstream.H"
#include "meshTools.H"
#include "momentOfInertia.H"
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
using namespace Foam;
int main(int argc, char *argv[])
{
argList::addOption
(
"cell",
"label",
"cell to use for inertia calculation, defaults to 0"
);
#include "setRootCase.H"
#include "createTime.H"
#include "createPolyMesh.H"
scalar density = 1.0;
{
label nPts = 6;
pointField pts(nPts);
pts[0] = point(4.495, 3.717, -4.112);
pts[1] = point(4.421, 3.932, -4.112);
pts[2] = point(4.379, 4.053, -4.112);
pts[3] = point(4.301, 4.026, -4.300);
pts[4] = point(4.294, 4.024, -4.317);
pts[5] = point(4.409, 3.687, -4.317);
face f(identity(nPts));
point Cf = f.centre(pts);
tensor J = Zero;
J = f.inertia(pts, Cf, density);
vector eVal = eigenValues(J);
tensor eVec = eigenVectors(J);
Info<< nl << "Inertia tensor of test face " << J << nl
<< "eigenValues (principal moments) " << eVal << nl
<< "eigenVectors (principal axes) " << eVec
<< endl;
OFstream str("momentOfInertiaTestFace.obj");
Info<< nl << "Writing test face and scaled principal axes to "
<< str.name() << endl;
forAll(pts, ptI)
{
meshTools::writeOBJ(str, pts[ptI]);
}
str << "l";
forAll(f, fI)
{
str << ' ' << fI + 1;
}
str << " 1" << endl;
scalar scale = mag(Cf - pts[f[0]])/eVal.component(findMin(eVal));
meshTools::writeOBJ(str, Cf);
meshTools::writeOBJ(str, Cf + scale*eVal.x()*eVec.x());
meshTools::writeOBJ(str, Cf + scale*eVal.y()*eVec.y());
meshTools::writeOBJ(str, Cf + scale*eVal.z()*eVec.z());
for (label i = nPts + 1; i < nPts + 4; i++)
{
str << "l " << nPts + 1 << ' ' << i + 1 << endl;
}
}
{
label nPts = 4;
pointField pts(nPts);
pts[0] = point(0, 0, 0);
pts[1] = point(1, 0, 0);
pts[2] = point(0.5, 1, 0);
pts[3] = point(0.5, 0.5, 1);
tetPointRef tet(pts[0], pts[1], pts[2], pts[3]);
triFaceList tetFaces(4);
tetFaces[0] = triFace(0, 2, 1);
tetFaces[1] = triFace(1, 2, 3);
tetFaces[2] = triFace(0, 3, 2);
tetFaces[3] = triFace(0, 1, 3);
scalar m = 0.0;
vector cM = Zero;
tensor J = Zero;
momentOfInertia::massPropertiesSolid(pts, tetFaces, density, m, cM, J);
vector eVal = eigenValues(J);
tensor eVec = eigenVectors(J);
Info<< nl
<< "Mass of tetrahedron " << m << nl
<< "Centre of mass of tetrahedron " << cM << nl
<< "Inertia tensor of tetrahedron " << J << nl
<< "eigenValues (principal moments) " << eVal << nl
<< "eigenVectors (principal axes) " << eVec
<< endl;
OFstream str("momentOfInertiaTestTet.obj");
Info<< nl << "Writing test tetrahedron and scaled principal axes to "
<< str.name() << endl;
forAll(pts, ptI)
{
meshTools::writeOBJ(str, pts[ptI]);
}
forAll(tetFaces, tFI)
{
const triFace& f = tetFaces[tFI];
str << "l";
forAll(f, fI)
{
str << ' ' << f[fI] + 1;
}
str << ' ' << f[0] + 1 << endl;
}
scalar scale = mag(cM - pts[0])/eVal.component(findMin(eVal));
meshTools::writeOBJ(str, cM);
meshTools::writeOBJ(str, cM + scale*eVal.x()*eVec.x());
meshTools::writeOBJ(str, cM + scale*eVal.y()*eVec.y());
meshTools::writeOBJ(str, cM + scale*eVal.z()*eVec.z());
for (label i = nPts + 1; i < nPts + 4; i++)
{
str << "l " << nPts + 1 << ' ' << i + 1 << endl;
}
}
{
const label celli = args.optionLookupOrDefault("cell", 0);
tensorField mI(momentOfInertia::meshInertia(mesh));
tensor& J = mI[celli];
vector eVal = eigenValues(J);
Info<< nl
<< "Inertia tensor of cell " << celli << " " << J << nl
<< "eigenValues (principal moments) " << eVal << endl;
J /= cmptMax(eVal);
tensor eVec = eigenVectors(J);
Info<< "eigenVectors (principal axes, from normalised inertia) " << eVec
<< endl;
OFstream str("cell_" + name(celli) + "_inertia.obj");
Info<< nl << "Writing scaled principal axes of cell " << celli << " to "
<< str.name() << endl;
const point& cC = mesh.cellCentres()[celli];
scalar scale = mag
(
(cC - mesh.faceCentres()[mesh.cells()[celli][0]])
/eVal.component(findMin(eVal))
);
meshTools::writeOBJ(str, cC);
meshTools::writeOBJ(str, cC + scale*eVal.x()*eVec.x());
meshTools::writeOBJ(str, cC + scale*eVal.y()*eVec.y());
meshTools::writeOBJ(str, cC + scale*eVal.z()*eVec.z());
for (label i = 1; i < 4; i++)
{
str << "l " << 1 << ' ' << i + 1 << endl;
}
}
Info<< nl << "End" << nl << endl;
return 0;
}
// ************************************************************************* //
|
