how to simulate acoustic waves?

[somiee]

HI group
I want to simulate acoustic wave propagation through finite element model using Ansys. I want to simulate P( primary) and S ( transverse) wave propagation through finite element model. My finite element model is cuboid just like CD case . I want to apply amplitude and frequencies at one of the faces of cuboid ( on small area).
how do I apply excitation to finite element model . I mean what type of analysis should i opt for?
Thanks
somiee