openfoam/applications/test/rigidBodyDynamics/spring/spring.C
Henry Weller 2870be400e rigidBodyDynamics/rigidBodySolvers: Added run-time selectable solvers to integrate the rigid-body motion
Currently supported solvers: symplectic, Newmark, CrankNicolson

The symplectic solver should only be used if iteration over the forces
and body-motion is not required.  Newmark and CrankNicolson both require
iteration to provide 2nd-order behavior.

See applications/test/rigidBodyDynamics/spring for an example of the
application of the Newmark solver.

This development is sponsored by Carnegie Wave Energy Ltd.
2016-04-12 11:33:20 +01:00

96 lines
2.8 KiB
C

/*---------------------------------------------------------------------------*\
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | Copyright (C) 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
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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
spring
Description
Simple weight and damped-spirng simulation with 1-DoF.
\*---------------------------------------------------------------------------*/
#include "rigidBodyMotion.H"
#include "masslessBody.H"
#include "sphere.H"
#include "joints.H"
#include "rigidBodyRestraint.H"
#include "rigidBodyModelState.H"
#include "IFstream.H"
#include "OFstream.H"
using namespace Foam;
using namespace RBD;
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
int main(int argc, char *argv[])
{
dictionary springDict(IFstream("spring")());
// Create the spring model from dictionary
rigidBodyMotion spring(springDict);
label nIter(readLabel(springDict.lookup("nIter")));
Info<< spring << endl;
// Create the joint-space force field
scalarField tau(spring.nDoF(), Zero);
// Create the external body force field
Field<spatialVector> fx(spring.nBodies(), Zero);
OFstream qFile("qVsTime");
OFstream qDotFile("qDotVsTime");
// Integrate the motion of the spring for 4s using a symplectic method
scalar deltaT = 0.002;
for (scalar t=0; t<4; t+=deltaT)
{
spring.newTime();
for (label i=0; i<nIter; i++)
{
spring.update
(
deltaT,
deltaT,
tau,
fx
);
}
// Write the results for graph generation
// using 'gnuplot spring.gnuplot'
qFile << t << " " << spring.state().q()[0] << endl;
qDotFile << t << " " << spring.state().qDot()[0] << endl;
}
Info<< "\nEnd\n" << endl;
return 0;
}
// ************************************************************************* //