Study and characterization of three-dimensional angular distributions of acoustic scattering from spheroidal targets

摘要

This paper reports a study of three-dimensional angular distributions of scattering strength associated with the flexural and Rayleigh resonances of a solid elastic spheroid, using the extended boundary condition method. The phenomenon of focusing of scattering strength into a disclike pattern caused by an elongated rigid spheroid is also investigated. Flexural resonances are found to produce strong scattering into four almost symmetrical lobes, as much as 20 dB above the nonresonance background. Rayleigh resonances are weaker, but significant portions of the scattered energy are directed into steep angles. The significance of this, and of the disclike scattering pattern due to the elongated rigid spheroid in waveguide situations, is discussed.