applications/test/rigidBodyDynamics/pendulumAndSpring: Another slightly more complex test

applications/test/rigidBodyDynamics/pendulumAndSpring/Make/files

+pendulumAndSpring.C
+
+EXE = $(FOAM_USER_APPBIN)/Test-pendulumAndSpring

applications/test/rigidBodyDynamics/pendulumAndSpring/Make/options

+EXE_INC = \
+    -I$(LIB_SRC)/rigidBodyDynamics/lnInclude
+
+EXE_LIBS = \
+    -lrigidBodyDynamics

applications/test/rigidBodyDynamics/pendulumAndSpring/pendulumAndSpring

+solver
+{
+    type Newmark;
+}
+
+// It is necessary to iterate for the Newmark solver
+nIter 2;
+
+bodies
+{
+    M
+    {
+        type            sphere;
+        parent          root;
+        mass            6e4;
+        radius          0.01;
+        transform       (1 0 0 0 1 0 0 0 1) (0 0 0);
+        joint
+        {
+            type composite;
+
+            joints
+            (
+                {
+                    type            Px;
+                }
+                {
+                    type            Rz;
+                }
+            );
+        }
+    }
+
+    m
+    {
+        type            sphere;
+        parent          M;
+        mass            6e3;
+        radius          0.01;
+        transform       (1 0 0 0 1 0 0 0 1) (0 -5 0);
+        mergeWith       M;
+    }
+}
+
+restraints
+{
+    spring
+    {
+        type            linearSpring;
+        body            M;
+        anchor          (0 0 0);
+        refAttachmentPt (0 0 0);
+        stiffness       1e5;
+        damping         0;
+        restLength      0;
+    }
+}
+
+// Set the gravitational acceleration
+g (0 -9.81 0);
+
+// Set the initial offset of the pendulum to 1.5m
+// and the angle of the pendulum to 30deg
+q (1.5 0.5235987);

applications/test/rigidBodyDynamics/pendulumAndSpring/pendulumAndSpring.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
+    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
+    pendulumAndSpring
+
+Description
+    Simple 2-DoF pendulum and spring simulation.
+
+\*---------------------------------------------------------------------------*/
+
+#include "rigidBodyMotion.H"
+#include "masslessBody.H"
+#include "sphere.H"
+#include "joints.H"
+#include "rigidBodyRestraint.H"
+#include "rigidBodyModelState.H"
+#include "IFstream.H"
+#include "OFstream.H"
+#include "constants.H"
+
+using namespace Foam;
+using namespace RBD;
+using namespace Foam::constant::mathematical;
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+int main(int argc, char *argv[])
+{
+    dictionary pendulumAndSpringDict(IFstream("pendulumAndSpring")());
+
+    // Create the pendulumAndSpring model from dictionary
+    rigidBodyMotion pendulumAndSpring(pendulumAndSpringDict);
+
+    label nIter(readLabel(pendulumAndSpringDict.lookup("nIter")));
+
+    Info<< pendulumAndSpring << endl;
+    Info<< "// Joint state " << endl;
+    pendulumAndSpring.state().write(Info);
+
+    // Create the joint-space force field
+    scalarField tau(pendulumAndSpring.nDoF(), Zero);
+
+    // Create the external body force field
+    Field<spatialVector> fx(pendulumAndSpring.nBodies(), Zero);
+
+    OFstream xFile("xVsTime");
+    OFstream omegaFile("omegaVsTime");
+
+    // Integrate the motion of the pendulumAndSpring for 100s
+    scalar deltaT = 0.01;
+    for (scalar t=0; t<20; t+=deltaT)
+    {
+        pendulumAndSpring.newTime();
+
+        for (label i=0; i<nIter; i++)
+        {
+            pendulumAndSpring.solve(deltaT, tau, fx);
+        }
+
+        // Write the results for graph generation
+        xFile << t << " " << pendulumAndSpring.state().q()[0] << endl;
+        omegaFile << t << " " << pendulumAndSpring.state().q()[1] << endl;
+    }
+
+    Info<< "\nEnd\n" << endl;
+
+    return 0;
+}
+
+
+// ************************************************************************* //

applications/test/rigidBodyDynamics/pendulumAndSpring/pendulumAndSpring.gnuplot

+#------------------------------------------------------------------------------
+# =========                 |
+# \\      /  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
+#     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/>.
+#
+# Script
+#     pendulumAndSpring.gnuplot
+#
+# Description
+#     Creates an PostScript graph file of Test-pendulumAndSpring results
+#
+#------------------------------------------------------------------------------
+
+reset
+
+set xlabel "Time/[s]"
+set ylabel "x"
+set y2label "omega"
+
+set ytics nomirror
+set y2tics
+
+set yrange [-1.5:1.5]
+set y2range [-35:35]
+
+set xzeroaxis
+
+set terminal postscript eps color enhanced solid
+set output "pendulumAndSpring.eps"
+
+plot \
+    "xVsTime" u 1:2 w l t "x", \
+    "omegaVsTime" u 1:(57.29578*$2) w l axes x1y2 t "omega"
+
+#------------------------------------------------------------------------------