Hi,
I am trying to simulate a single-element transducer in 2D, with a focus gain of 9.11 ( so the pressure at the focal point would be 9.11 assuming the pressure at the surface of the source is 1). I set this up by making an arc of sources at one end of the grid and having sensors at and around the focal point to measure the pressure. This gives me correct result for only very specific (and seemingly arbitrary) combinations of grid point spacing and timestep.
I've noticed that although the timestep dt is less than the recommended d/cmax, the simulation often does not give me the expected results. In addition, changing the timestep even slightly has a very large effect on the max pressure reading, which I did not think was supposed to happen. Any advice on how to pick the right timestep or about anything I may be doing wrong here?
Thank you.