http://www.k-wave.org/forum/topic/difference-between-simulated-and-theoretical-dispersion Support for the k-Wave MATLAB toolbox en-US Tue, 12 May 2026 23:36:54 +0000 http://bbpress.org/?v=1.0.2 q http://www.k-wave.org/forum/search.php http://www.k-wave.org/forum/topic/difference-between-simulated-and-theoretical-dispersion#post-8514 Mon, 25 Apr 2022 19:33:51 +0000 bencox 8514@http://www.k-wave.org/forum/ <p>Hi Magnus, </p> <p>If the material properties are quite different, then it is quite slow to converge, as you observed. For modelling wave propagation in homogeneous media, or media with small variations in the acoustic properties (like soft biological tissue), you can get away with many fewer points per wavelength. </p> <p>Best wishes<br /> Ben </p> http://www.k-wave.org/forum/topic/difference-between-simulated-and-theoretical-dispersion#post-8489 Thu, 24 Mar 2022 08:56:17 +0000 magnus 8489@http://www.k-wave.org/forum/ <p>Hi,</p> <p>While simulating Lamb waves in a plate using pstdElastic2D, I noticed a difference between theoretical and simulated dispersion. I'm modelling a steel plate of 6.8 mm thickness and expect phase velocities of 1500-2000m/s, source frequency is 60kHz, so the expected wavelength should be around 2.5-3cm. The observed disagreement was while using a mesh grid with step-size dx=dy=0.2 mm (i.e ~125 grid points per wavelength). I have done a convergence test where I reduced the mesh grid step size and I managed to get the results to agree if I went down to a dx=dy=0.1 mm, which is computationally too costly for what I need to do.</p> <p>Is there an explanation for this behaviour? My impression has been that k-Wave and the pseudospectral method would work also with relatively sparse grids compared to the wavelength.</p> <p>Best regards<br /> Magnus </p>