After having done a number of simulations solving the heat equation in fractal domains, we are ready to do the same for the wave equation. This animation shows solutions of the wave equation outside 4 different approximations of a Sierpinski carpet. It illustrates why fractal materials can have an insulating effect, by trapping and reflecting sound waves.
See • Wave hitting a Sierpin... for a version showing the energy density instead of the height of the waves.
Level 1: 0:00
Level 2: 1:32
Level 3: 3:05
Level 4: 4:36
(courtesy of My Craft)
Music: "The Emperor's Army", by Jeremy Blake@RedMeansRecording
See also images.math.cnrs.fr/Des-ondes... for more explanations (in French) on a few previous simulations of wave equations.
The simulation solves the wave equation by discretization. The algorithm is adapted from the paper hplgit.github.io/fdm-book/doc...
Reflections on the boundaries of the rectangle are minimized by adding Neumann-type boundary conditions on the time-derivative of the wave.
C code: github.com/nilsberglund-orlea...
www.idpoisson.fr/berglund/sof...
Many thanks to my colleague Marco Mancini for helping me to accelerate my code!
26 май 2024