Hello Erik,
I am trying to do similar analysis of impedance tube to determine absorption coefficient of some specimen. I tried to replicate your settings but I don't see exactly how you used boundary conditions. I set Port on input face and Radiation Boundary at the same face. I also put loading (acoustic pressure) to the same face. Is it correct?
The problem is that when I try to evaluate absorption coefficient on a Port (input face), there is an error saying: "The input power at the driven port is equal to zero". Could you please tell me what could cause this problem? Or could you please tell me if my BCs are different than yours?
Thanks in advance
Have a nice day