This is a kind of rattle with pebbles inside - if you shake it, they hit the walls and generate the sound. nWhat I want to do was to apply 1N force on one face of the inner wall, like you do in harmonic analysis, in order to obtain pressure generated at some point by the excitation in spectrum of 10Hz to 10kHznnThe domain is a sphere. I applied radiation boundary on the external face of the sphere. I also defind physics and acoustics region, as well as fluid-solid interface. I also applied fixed support to the bottom of this object.nnI tried to play around with mass source, but somehow the results are wrong - I have done spectrum analysis of real sound gen erated by this rattle, as well as modal analysis of this exact model and both resulted in frequences around 9.2kHz and 9.5kHz, meanwhile the results I got from this analysis are presented belownI'd appreciate any helpn