Modeling of acoustic scattering by sphere on a planar seabed

A model of acoustic scattering from spherical target above a planar seabed is advanced to a condition of irradiation by a point source, with both of T matrix method and complex images method. Compared to the model of Fawcett and Lim, this model could be used to calculate scattering field from a target above a planar interface in three dimension space. Comparing some coefficients by complex images method with that by analytical formula or numerical quadrature, the computing method of the model is examined to be efficient and accurate. In additions numerical examples of a rigid sphere and an elastic spherical shell are compared for scattering field from the target on a fluid seabed, and the scattering field dependent angle is investigated from the different grazing angle of incident wave. In order to verify the model, an experiment is carried out to measure scattered field received by vertical array in laboratory. Data are analyzed and compared with calculated results.