Hi Rohan,
The free surface of the solid body that is meshed with FLUID221 elements needs to have a Free Surface boundary condition applied. See section 7.1.4 of the Acoustic Analysis Guide in Ansys Help.
https://ansyshelp.ansys.com/account/secured?returnurl=/Views/Secured/corp/v231/en/ans_acous/acous_bc_apply.html
Did the fluid body get meshed with tet or hex shaped elements?
You are navigating away from the AIS Discovery experience