http://www.k-wave.org/forum/topic/kspaceorder2d-and-pstdelastic2d-simultaneous-use Support for the k-Wave MATLAB toolbox en-US Tue, 12 May 2026 22:32:32 +0000 http://bbpress.org/?v=1.0.2 q http://www.k-wave.org/forum/search.php http://www.k-wave.org/forum/topic/kspaceorder2d-and-pstdelastic2d-simultaneous-use#post-8838 Thu, 15 Jun 2023 15:49:05 +0000 masud407 8838@http://www.k-wave.org/forum/ <p>Dr. Treeby, I tried with inserting velocity as input instead of stress, still, it can't track the shear stress. Am I supposed to get the similar result for velocity input instead of stress?</p> <p>source.u_mask = sensor.mask;<br /> source.ux=sensor_data_fluid.ux;<br /> source.uy=sensor_data_fluid.uy;<br /> source.uz=sensor_data_fluid.uz;<br /> sensor_data_elastic = pstdElastic3D(kgrid, medium, source, sensor, input_args{:});</p> <p>Also, I am not sure what to use for source. mask. I want to use the same transducer for both as a source of ARF and also for tracking. Can you please tell me a bit about selecting the source. u_mask/source.s_mask? </p> http://www.k-wave.org/forum/topic/kspaceorder2d-and-pstdelastic2d-simultaneous-use#post-8833 Tue, 13 Jun 2023 21:12:37 +0000 masud407 8833@http://www.k-wave.org/forum/ <p>Dr. Treeby,</p> <p>Thanks, I actually removed the (rho * c) term and found that I got the normal stress, but it can't track the shear stress at all. I will try with a velocity source in the elastic code (instead of a stress source) as per your suggestion. </p> http://www.k-wave.org/forum/topic/kspaceorder2d-and-pstdelastic2d-simultaneous-use#post-8832 Tue, 13 Jun 2023 19:48:12 +0000 Bradley Treeby 8832@http://www.k-wave.org/forum/ <p>The inputs are in units of pressure (not particle velocity) so you can remove the scaling by the impedance (rho * c). Alternatively, also use a velocity source in the elastic code (instead of a stress source). </p> http://www.k-wave.org/forum/topic/kspaceorder2d-and-pstdelastic2d-simultaneous-use#post-8827 Tue, 13 Jun 2023 01:08:53 +0000 masud407 8827@http://www.k-wave.org/forum/ <p>I used transducer.active_elements_mask as source.s_mask as following. The simulation runs but, the stress value are very low that it doesn't show anything the plot. Here is the code for that:</p> <p>input_signal = toneBurst(1/kgrid.dt, tone_burst_freq, tone_burst_cycles);<br /> input_signal = (source_strength ./ (rho1 .* cp1)) .* input_signal;<br /> source.s_mask = transducer.active_elements_mask;<br /> source.sxx = -input_signal;<br /> source.syy = source.sxx;<br /> sensor_data_elastic = pstdElastic3D(kgrid, medium, source, sensor, input_args{:}); </p> http://www.k-wave.org/forum/topic/kspaceorder2d-and-pstdelastic2d-simultaneous-use#post-8826 Mon, 12 Jun 2023 23:09:52 +0000 masud407 8826@http://www.k-wave.org/forum/ <p>Thanks, I am trying to replicate this example for a linear array transducer which will act as a source as well as a sensor. The kspaceFirstOrder3D portion works fine as I used a transducer. input signal as the source. where<br /> input_signal = (source_strength ./ (rho1 .* cp1)) *toneBurst(1/kgrid.dt, tone_burst_freq, tone_burst_cycles);</p> <p>However for the pstdElastic3D simulation, I need to specify source.mask, source.sxx, and source.syy separately. For source Sxx, I am using -input signal=Sxx, but what should be the mask (source.mask) for transducer array? Thanks </p> http://www.k-wave.org/forum/topic/kspaceorder2d-and-pstdelastic2d-simultaneous-use#post-8822 Mon, 12 Jun 2023 08:10:05 +0000 Bradley Treeby 8822@http://www.k-wave.org/forum/ <p>This is because the acoustic equation is formulated in terms of pressure and particle velocity (and acoustic density), while the elastic equation is formed in terms of stress and particle velocity, so the source must be set in terms of stress. In the parts of the domain where the shear speed is zero, the diagonal parts of the stress tensor are equal to the negative of the pressure (hence the code in the snippet you posted). </p> http://www.k-wave.org/forum/topic/kspaceorder2d-and-pstdelastic2d-simultaneous-use#post-8821 Mon, 12 Jun 2023 02:11:08 +0000 masud407 8821@http://www.k-wave.org/forum/ <p>Dr. Treeby, thanks I got it. I have another follow-up question. After completing the kspaceFirstOrder2D, the example cleared out the source and used the following line to redefine the medium:</p> <p>clear source<br /> source.s_mask = source_mask;<br /> source.sxx = -source_strength*toneBurst(1/kgrid.dt, source_freq, source_cycles);<br /> source.syy = source.sxx;</p> <p>I am wondering what is the reason for that. Thanks </p> http://www.k-wave.org/forum/topic/kspaceorder2d-and-pstdelastic2d-simultaneous-use#post-8819 Fri, 09 Jun 2023 22:22:02 +0000 Bradley Treeby 8819@http://www.k-wave.org/forum/ <p>If you open the example from within the MATLAB help browser, you can click to open and run the code. </p> http://www.k-wave.org/forum/topic/kspaceorder2d-and-pstdelastic2d-simultaneous-use#post-8818 Fri, 09 Jun 2023 21:06:04 +0000 masud407 8818@http://www.k-wave.org/forum/ <p>Dr. Treeby, thanks for your reply. I added the wrong link in my post. Here is the original one:</p> <p><a href="http://www.k-wave.org/documentation/example_ewp_shear_wave_snells_law.php" rel="nofollow">http://www.k-wave.org/documentation/example_ewp_shear_wave_snells_law.php</a></p> <p>It mentioned that The simulation is run twice, first using the fluid code kspaceFirstOrder2D, and then using the elastic code pstdElastic2D. I can see the separate example of pstdElastic2D code, but how can I use the outcome of kspaceFirstOrder2D as the input of pstdElastic2D code? Thanks </p> http://www.k-wave.org/forum/topic/kspaceorder2d-and-pstdelastic2d-simultaneous-use#post-8817 Fri, 09 Jun 2023 21:05:59 +0000 masud407 8817@http://www.k-wave.org/forum/ <p>Dr. Treeby, thanks for your reply. I added the wrong link in my post. Here is the original one:</p> <p><a href="http://www.k-wave.org/documentation/example_ewp_shear_wave_snells_law.php" rel="nofollow">http://www.k-wave.org/documentation/example_ewp_shear_wave_snells_law.php</a></p> <p>It mentioned that The simulation is run twice, first using the fluid code kspaceFirstOrder2D, and then using the elastic code pstdElastic2D. I can see the separate example of pstdElastic2D code, but how can I use the outcome of kspaceFirstOrder2D as the input of pstdElastic2D code? Thanks </p> http://www.k-wave.org/forum/topic/kspaceorder2d-and-pstdelastic2d-simultaneous-use#post-8816 Fri, 09 Jun 2023 20:48:39 +0000 Bradley Treeby 8816@http://www.k-wave.org/forum/ <p>What do you mean by simultaneously? Note, the imaging examples are all in 3D to capture the out of plane effects. There are some general examples of how to use the <code>pstdElastic2D</code> code under the "Elastic Wave Propagation" heading. </p> http://www.k-wave.org/forum/topic/kspaceorder2d-and-pstdelastic2d-simultaneous-use#post-8815 Fri, 09 Jun 2023 18:44:53 +0000 masud407 8815@http://www.k-wave.org/forum/ <p>Can anyone please explain to me how I can use Kspaceorder2D and pstdelastic2D simultaneously for the following example?</p> <p><a href="http://www.k-wave.org/documentation/example_us_beam_patterns.php" rel="nofollow">http://www.k-wave.org/documentation/example_us_beam_patterns.php</a></p> <p>What should be the input for the pstdelastic2d case? Any code example for this type of study? Thanks </p>