http://www.k-wave.org/forum/topic/how-to-calculate-particle-velocity Support for the k-Wave MATLAB toolbox en-US Tue, 12 May 2026 23:30:35 +0000 http://bbpress.org/?v=1.0.2 q http://www.k-wave.org/forum/search.php http://www.k-wave.org/forum/topic/how-to-calculate-particle-velocity#post-8368 Thu, 16 Dec 2021 10:44:12 +0000 Bradley Treeby 8368@http://www.k-wave.org/forum/ <p>Hi monmo,</p> <p>The variable <code>ux_sgt</code> is the velocity NOT staggered in space, and NOT staggered in time (see e.g., line 46 in V1.3). It has to be at the same points in space and time to multiply by the pressure.</p> <p>The particle velocity returned by <code>sensor.record = {&#39;u&#39;}</code> is staggered in BOTH space and time.</p> <p>The partial velocity returned by <code>sensor.record = {&#39;u_non_staggered&#39;}</code> is NOT staggered in space but IS staggered in time.</p> <p>Thus, the particle velocity recovered from the intensity will match <code>u_non_staggered</code> only after unstaggering the latter in time.</p> <p>Hope that helps,</p> <p>Brad. </p> http://www.k-wave.org/forum/topic/how-to-calculate-particle-velocity#post-8346 Sun, 14 Nov 2021 12:37:15 +0000 monmo 8346@http://www.k-wave.org/forum/ <p>I read the code, but there are various types of particle velocities, and I don't understand the difference correctly.</p> <p>【various types of particle velocities】<br /> ux_sgx(=sensor_data.ux) : 1/2 staggered shift to time and space(?)<br /> ux_shifted(=sx_nonstaggerd) : 1/2 staggered shift in time (?)<br /> ux_sgt : unstaggerd</p> <p>ux_sgt is used to calculate the sound intensity with "kspaceFirstOrder_saveIntensity".<br /> <code>sensor_data(sensor_mask_index).Ix = sensor_data(sensor_mask_index).p .* ux_sgt;</code></p> <p>Therefore, I thought that ux_sgt was unstaggered.<br /> If it is correct, I feel that it is correct to find'u'from I / p.</p> <p>Perhaps I don't understand enough. thank you. </p> http://www.k-wave.org/forum/topic/how-to-calculate-particle-velocity#post-8343 Sun, 14 Nov 2021 12:22:31 +0000 monmo 8343@http://www.k-wave.org/forum/ <p>Thank you as always</p> <p>I want to calculate the particle velocity by analysis using kspace_FirstOrder3d.m.</p> <p>I think there are two ways to do this.</p> <p>1. Add 'u' to senseor.record</p> <p>2. Add 'I'and'p' to sensor.record and obtain from u = I / p.<br /> I need All of 'I','u','p', so I thought would save memory for'p' when calculated this way.</p> <p>But when I calculated using two methods, I got different answers of 'u'.</p> <p>Which method is appropriate for calculating the particle velocity correctly? </p>