Erik Kostson
Ansys Employee

I think it could be possible to use that one (general admittance matrix YMAT), but how you can derive the terms I do not know (it is quite complex). As I mentioned the square grid option can not be used for your disc, it only applies to a curved perforated pipe (as shown in the image below), and you do not have that. Also really think why you need to model all this (what is the purpose of the analysis).

One can also use to certain extent the Delany-Bazley perforated material model for a rigid/steel perforated disc (you need to know the fluid resistivity though). Of course then we use this say for a complex set up say in a silencer, and before we can check the model say with the measured transmission loss of the perforated disc alone sitting in an impedance tube.

All the best