Acoustic radiation calculations by a hybrid separation of variables - boundary element method

A new hybrid method (HM) solution to the radiation problem
is presented. The HM is based on the separation of variables method and the
boundary element method. An idea of the HM consists in the modelling of acoustic
variables only by the boundary element method using their discrete values. The
geometry of the problem is described exactly. The HM enables to solve boundary
acoustic problem in an orthogonal curvilinear system of coordinates. In the
paper the method is applied to acoustic radiation by axially vibrating cup or
ring set on the sphere. The hybrid radiation solution is compared to the well
known analytical one.