Numerical simulations of sound scattering on a partly rough pressure-release surface using the boundary element method

We consider the scattering of a plane sound wave at a rough water-air interface using numerical simulations. We describe our method in detail and demonstrate its functionality with simple examples. The main advantage of the method is that there are no limitations on the relation between the shape of the surface and the incident wave. This allows us to consider large Rayleigh parameters, shading, and multiple scattering. In the method, the solution of the Helmholtz equation in the form of an integral over the domain boundary is used only in the inner domain. In the outer domain, separation of variables is used to obtain a non-local integral boundary condition on an artificial boundary.