Hello, I need to simulate oscillations of the microcantilever in the liquid medium: look at the Eigenfrequencies, and as well at the Frequency Domain. However, I have problems with adding any medium. As far as I understood, the proper way to do so is Acoustic-Structural analysis ( as demonstrated here. But in our academic COMSOL there is no such module (only Pressure Acoustics in the Acoustics module). Another option to include effect of medium to the eigen frequencies, seemed for me the thin film damping. But I don't fully understand if I can really apply it for cantilever immersed in the bulk solution: in thin film damping analysis depends on distance between cantilever (wall) and reference surface, which is located under the bottom of cantilever. But such way the only included damping is created by some liquid layer under the cantilever. I don't understand, how can I include also damping created by liquid which is on top of the cantilever (can be such reference surface above cantilever, with negative 'height of wall above reference surface', or this wouldn't make any sense?). And in general, if it makes any sense to give this distance between cantilever and reference surface some high value, assuming that it simulates then situation of the bulk solution.
And finally, there is also a module called Fluid-Structure interaction, but as far as I understood it won't suit this case, since in my case there is no flow at all. And also this module doesn't seem to provide any eigenfrequencies analysis.