Discussion Forum

Hi,

I am using the COMSOL acoustics module to simulate an underwater acoustic panel, which consists of water-rubber (with a cylinder air)-steel-air model; both in 2D and 3D.

I have tested the solution in the 2D case against theoretical (analytical) models and the simulation is quite precise, however, when trying to replicate it in the 3D domain, I get wrong results. In particular, I’m plotting the transmission, reflection and absorption coefficients, and, as you can see below, they are quite different, specially for high frecuencies.

I’m considerating in both models an infinitely repeated panel (using periodic condition when it is needed); PML/plane wave radiation (so the wave won’t bounce) in the outer contours; a background pressure field; and of course, the same parameters for materials and geometries.

I have tried many things already, changing simulations options, changing the mesh, from "normal" to "extra fine", but apparently it doesn't improve the results in any case. Sometimes, when I'm trying different options, my 3D simulations even shows an empty graphic.

Of course, I have more trust in 2D model, so I suppose the problem it'd be in 3D model. Does anybody have an idea about why the results are not consistent?

I have attached the files below, if someone could please take a look I’d be very grateful.

Also, I cleared the mesh and the solutions before saving and uploading it onto here.

Thanks!