Discussion Forum

Hello Dear Friends,

I want to simulate a simple model via transient analysis. My model is similar to "porous_absorber.mph" (4.3b). My model is more simple. Fundamental difference between two models is that porous absorber uses frequency domain analysis (acpr), but my model uses transient analysis (actd).
There is rectangle (water domain) in my model as geometry. Top boundary is sound soft boundary (to simulate air-water interface). Bottom boundary is plane wave radiation boundary. Left and right boundaries are periodic condition boundaries (floquet periodicity). Plane wave (finite duration: 1 ms) is radiated from bottom boundary then it is reflected/scattered from top boundary. I want to observe scattered pressure in the water domain.
I can do that for normal incidence very accurately. But when I change the angle of incidence (to oblique incidences, e.g. pi/4), shape of radiated plane wave and naturally reflected/scattered wave is not what it is supposed to be.
What can I do in order to fix that? Should I use model coupling? If yes, what would it be?

In "porous absorber" example, wave number of incident field (k0) is defined as a variable: k0=intopx(acpr.k).
In my model I could not define k0 in this way (k0=intopx(actd.k), because transient analysis does not give a permission to do that. I define k0 as 2*pi*lambda.

Thank you for your help...