Pure Elastic Resonance Scattering of an Obliquely Incident Plane Acoustic Wave by a Submerged Infinite Cylinder

Although sound scattering by submerged elastic cylinders has been extensively studied,only a few works aimed at the case of obliquely incidence.In this paper,we derive a simple and explicit expression of the pure elastic resonance scattering function of a submerged infinite cylinder excited by a plane wave at obliquely incidence.For backscattering of a solid aluminum cylinder we have calculated (a) the partial resonance spectra n=0-7,(b) the far field total form functions and the pure elastic resonance form functions,(c) the complex resonance poles in the normalized complex frequency plane,and (d) the dispersion curves of the first several families of belieal waves,at various incident angles in details.We especially discuss the generation mechanism and properties of the complementary resonatlce modes existing only at obliquely incidence.Our attentions are also focused on the variance of the resonance spectra with the incident angle,particularly near several critical angles.