Three-dimensional problems of acoustic waves scattering by infinite flexible plates covering a stratified liquid layer which lies on a homogeneous half-space are considered. An optical theorem for the problems is derived. The identifies of the theorem differ from that being previously obtained for homogeneous acoustic media in terms corresponding to normal waves of a waveguide formed by the layer. At large distances the scattered field forms a divergent spherical wave in the half-space and a set of circular waves in the waveguide channel. The identities are obtained for two cases of excitation: the excitation by a plane acoustic wave incident from the half-space and the excitation by a plane normal wave propagating along the plate. The derived identities can be useful from independent confirmation of numerical calculation data.
|Publication status||Published - 1993|