http://www.k-wave.org/forum/topic/changing-the-speed-of-sound Support for the k-Wave MATLAB toolbox en-US Wed, 13 May 2026 17:27:22 +0000 http://bbpress.org/?v=1.0.2 q http://www.k-wave.org/forum/search.php http://www.k-wave.org/forum/topic/changing-the-speed-of-sound#post-6459 Sun, 13 May 2018 20:04:49 +0000 Bradley Treeby 6459@http://www.k-wave.org/forum/ <p>Hi bentower,</p> <p>Have you looked at <a href="http://www.k-wave.org/documentation/example_tvsp_doppler_effect.php">The Doppler Effect Example</a>? (Open the code from the MATLAB help browser.) This might do what you're after.</p> <p>Brad. </p> http://www.k-wave.org/forum/topic/changing-the-speed-of-sound#post-6450 Fri, 11 May 2018 02:18:22 +0000 bentower 6450@http://www.k-wave.org/forum/ <p>Update: I've since realized why my proposed solution for the first question 1) would not work, as the speed of the waves traveling with respect to the sources will still be inaccurate. Thus, my 2nd question still stands. Is there a better way I can smooth out the pressure 'pulses' that I get from having the monopole linger at each node for ~200 timesteps before moving onto the next node? </p> http://www.k-wave.org/forum/topic/changing-the-speed-of-sound#post-6449 Thu, 10 May 2018 05:57:28 +0000 bentower 6449@http://www.k-wave.org/forum/ <p>I'm trying to simulate a monopole moving back and forth in air along an arc. I can get the simulation to run fine when the timestep is made by kgrid.makeTime, but the issue is I would like it to take a certain amount of time (0.01 seconds) for the monopole to move from one end of the arc to the other. Even when the CFL condition is pushed so that Cmax = 0.9, the timestep made by kgrid.makeTime is too small such that dt * the number of nodes along the arc &lt;&lt; 0.01 seconds. I have already increased the number of points along the arc to be the maximum allowable by the grid size. I could decrease the grid size to allow for more points along the arc, but this would necessitate a smaller dt from the CFL condition.</p> <p>My questions are as follows: </p> <p>1. The first and most promising solution I thought of was to decrease the speed of sound in the simulation. Unfortunately, in order for the times to match, I would need to decrease the sound speed to ~1m/s. The simulation runs, but is this reduction of the sound speed too un-physical? What are the ramifications of decreasing the sound speed to such an extent?</p> <p>2. The second solution I thought of was to have the monopole linger at each node for long enough for the times to match. However, this leads to ripples that occur each time the source moves nodes after lingering for ~200 timesteps. Is there a better approach to accomplish this?</p> <p>Thank you! </p>