Hi Eirk

I did try coupled field harmonic. I have defined the structural region but cannot define the acoustic region. Please see the image below. The purple region is the fluid domain. I selected to define it as an acoustic region, but it's not accept it.


It's a 2D model. Purple region is Fluid (water-liquid material), and this curved surface is a piezoelectric transducer immersed in the fluid.

I am using a licensed academic version of Auckland Uni. of Technology.