k-Wave User Forum » Topic: Wave propagation in three mediums

k-Wave User Forum » Topic: Wave propagation in three mediums http://www.k-wave.org/forum/topic/wave-propagation-in-three-mediums Support for the k-Wave MATLAB toolbox en-US Wed, 13 May 2026 00:04:52 +0000 http://bbpress.org/?v=1.0.2 <![CDATA[Search]]> q http://www.k-wave.org/forum/search.php savpetr on "Wave propagation in three mediums" http://www.k-wave.org/forum/topic/wave-propagation-in-three-mediums#post-5177 Wed, 29 Jul 2015 10:11:09 +0000 savpetr 5177@http://www.k-wave.org/forum/ Hi Brad, Thank you so much. The code works. Savino Bradley Treeby on "Wave propagation in three mediums" http://www.k-wave.org/forum/topic/wave-propagation-in-three-mediums#post-5175 Tue, 28 Jul 2015 12:38:41 +0000 Bradley Treeby 5175@http://www.k-wave.org/forum/ Hi savpetr, You have both an instability and a plot scale issue. If you change the plot scale to <code>[-80, 80]</code> and the definition of the time array to: <pre><code>% create the time array CFL = 0.1; [kgrid.t_array, dt] = makeTime(kgrid, max(max(medium.sound_speed)), CFL);</code></pre> your simulation should run. Brad savpetr on "Wave propagation in three mediums" http://www.k-wave.org/forum/topic/wave-propagation-in-three-mediums#post-5168 Thu, 23 Jul 2015 11:48:22 +0000 savpetr 5168@http://www.k-wave.org/forum/ Hi Anthony, this is my code: clear all; clc; % ========================================================================= % SIMULATION % ========================================================================= l1 = 0.01; l2 = 0.08; l3 = 0.01; l_tot = l1 + l2 + l3; % create the computational grid Nx = 128; % number of grid points in the x (row) direction Ny = 128; % number of grid points in the y (column) direction dx = l_tot/Nx; % grid point spacing in the x direction [m] dy = dx; % grid point spacing in the y direction [m] kgrid = makeGrid(Nx, dx, Ny, dy); % define the properties of the propagation medium medium.sound_speed = 1250*ones(Nx, Ny); medium.density = 835*ones(Nx, Ny); medium.sound_speed(round((l1+l2)/dx):end,:) = 5850; medium.density(round((l1+l2)/dx):end, :) = 7800; medium.sound_speed(1:round(l1/dx), : ) = 341; medium.density(1:round(l1/dx), : ) = 1.2; % create the time array [kgrid.t_array, dt] = makeTime(kgrid, max(max(medium.sound_speed))); % define a single source point source.u_mask = zeros(Nx, Ny); source.u_mask(end - Nx/4, Ny/2) = 1; % define a time varying sinusoidal velocity source in the x-direction source_freq = 0.25e6; % [Hz] source_mag = 2/(min(min(medium.sound_speed))*min(min(medium.density))); source.ux = -source_mag*sin(2*pi*source_freq*kgrid.t_array); % filter the source to remove high frequencies not supported by the grid source.ux = filterTimeSeries(kgrid, medium, source.ux); % define a single sensor point sensor.mask = zeros(Nx, Ny); sensor.mask(Nx/2, Ny/2) = 1; % define the acoustic parameters to record sensor.record = {'p', 'p_final'}; % run the simulation sensor_data = kspaceFirstOrder2D(kgrid, medium, source, sensor, 'PlotScale', [-0.5, 0.5]); I saw 'Monopole Point Source In A Homogeneous Propagation Medium Example'. Why this code doesn't work? Anthony on "Wave propagation in three mediums" http://www.k-wave.org/forum/topic/wave-propagation-in-three-mediums#post-5138 Fri, 10 Jul 2015 10:42:24 +0000 Anthony 5138@http://www.k-wave.org/forum/ Hi savpetr, It seems correct to me. Anyway, I don't think that the error message you get come from your medium definition... Did you change anything else in the example? Could you post your complete code? Anthony PS : By the way, you seem to have very large differences in the density and sound speed, see related topics but it may cause (other) problems. savpetr on "Wave propagation in three mediums" http://www.k-wave.org/forum/topic/wave-propagation-in-three-mediums#post-5136 Thu, 09 Jul 2015 18:17:20 +0000 savpetr 5136@http://www.k-wave.org/forum/ Hi Anthony, Thank you for your answer. This is my code: medium.sound_speed = 1250*ones(Nx, Ny); medium.density = 835*ones(Nx, Ny); medium.sound_speed(1:round(l1/dx),:) = 5850; medium.density(1:round(l1/dx), :) = 7800; medium.sound_speed(round(l2/dx):round(l3/dx), : ) = 341; medium.density(round(l2/dx):round(l3/dx), : ) = 1.2; l1,l2 and l3 are the distances from the start of the grid. Anthony on "Wave propagation in three mediums" http://www.k-wave.org/forum/topic/wave-propagation-in-three-mediums#post-5135 Thu, 09 Jul 2015 15:00:12 +0000 Anthony 5135@http://www.k-wave.org/forum/ Hi savpetr The number of media should not change anything. The waitbar is only the bar which shows the progress of the computations. Could you post your code? To define different media you can set heterogeneous maps of density, speed etc. in the variables <code>medium.sound_speed</code>, <code>medium.sound_speed</code> etc. Best regards, Anthony savpetr on "Wave propagation in three mediums" http://www.k-wave.org/forum/topic/wave-propagation-in-three-mediums#post-5134 Thu, 09 Jul 2015 12:17:32 +0000 savpetr 5134@http://www.k-wave.org/forum/ Hi, I'm new to K-WAVE. I want to simulate the 2D propagation in three different mediums. I did it with two mediums without problems. When I define three mediums and run the simulation I receive the error: "Error using waitbar (line 90) The second argument must be a message string or a handle to an existing waitbar." How can I solve it? Thanks.