77 lines
2.3 KiB
Gnuplot
77 lines
2.3 KiB
Gnuplot
#------------------------------------------------------------------------------
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# ========= |
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# \\ / F ield | OpenFOAM: The Open Source CFD Toolbox
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# \\ / O peration |
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# \\ / A nd | Copyright (C) 2010-2010 OpenCFD Ltd.
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# \\/ M anipulation |
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#-------------------------------------------------------------------------------
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# License
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# This file is part of OpenFOAM.
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#
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# OpenFOAM is free software: you can redistribute it and/or modify it
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# under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
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# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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# FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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# for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with OpenFOAM. If not, see <http://www.gnu.org/licenses/>.
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#
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# Script
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# shm.gnuplot
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#
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# Description
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# Creates an .eps graph of OpenFOAM results vs analytical solution
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# for a simple harmonic motion dynamicMesh case
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#
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#------------------------------------------------------------------------------
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reset
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set samples 2000
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k = 5000.0
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m = 9.6
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c = 50.0
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a = -0.1
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omega = sqrt(k/m)
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zeta = c/(2.0*m*omega)
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phi = atan((sqrt(1.0 - zeta**2))/zeta)
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A = a/sin(phi)
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pos(A, t, omega, phi, zeta) = A*exp(-zeta*omega*t)*sin(sqrt(1-zeta**2)*omega*t + phi)
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vel(A, t, omega, phi, zeta) = \
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A*exp(-zeta*omega*t)*\
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( \
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sqrt(1-zeta**2)*omega*cos(sqrt(1-zeta**2)*omega*t + phi) \
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- zeta*omega*sin(sqrt(1-zeta**2)*omega*t + phi) \
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)
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set xlabel "Time/[s]"
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set ylabel "Position"
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set ytics nomirror
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set y2tics
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set yrange [-0.1:0.1]
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set y2range [-2:2]
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set xzeroaxis
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set terminal postscript eps color enhanced solid
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set output "shm.eps"
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plot \
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"t_vs_cm" u 1:($2 - 0.6) w l t "Simulation, centre of mass relative to start", \
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pos(A, x, omega, phi, zeta) w l t "Analytical solution, centre of mass", \
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"t_vs_lv" u 1:2 w l axes x1y2 t "Simulation, vertical velocity", \
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vel(A, x, omega, phi, zeta) w l axes x1y2 t "Analytical solution, vertical velocity"
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#------------------------------------------------------------------------------
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