You do not mention which kind of waves you are interested in. Hence, enclosed are some suggestions on multiphysics solvers. There might other options that are better if you have particular reqiurements.
Here is a link to a freeware multiphysics solver called Elmer. I have never used it but perhaps it can do the job?
https://www.csc.fi/web/elmer
Otherwise, COMSOL Multyphysics is a popular multiphysics solver