Oblique Rayleigh wave scattering by a cylindrical cavity

The problem of oblique wave scattering of a Rayleigh wave by a cylindrical cavity in an elastic half-space is solved using the multipole expansion method. Whereas in the analogous water-wave problem a single scalar field is expressed as an infinite multipole expansion, and in the Rayleigh wave case with normal incidence two scalar fields suffice, here we require three coupled scalar multipole expansions. The focus of our numerical results is on the energy scattered by the cavity and in particular the proportion of the incident wave energy that is reflected and transmitted in the form of Rayleigh waves and the proportion that is transformed into cylindrical bulk waves which propagate into the half-space.