Pure elastic resonance scattering of an obliquely incident plane acoustic wave by a submerged infinite cylinder

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Pure elastic resonance scattering of an obliquely incident plane acoustic wave by a submerged infinite cylinder

Although sound scattering by submcrged elastic cylinders was 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 clastic resonance scattering function of a submerged infinite cylinder excited by a plane wave at obliquely incidcnce. For backscattering of a solid aluminum cylinder we calculated (a) the partial resoriance spectra n=0 to 7, (b) the far field total form functions and the pure elastic resonance form the functions, (c) the complex resonance poles in the normalized complex frequency plane and (d) the dispersion curves of the first several families of helical waves, at various incident angles in details. It was discussed that the generation mechanism and properties of the complementary resonance modes are existed only at oblique incidence. Our attention is also focused on the variance of the resonance spectra with the incident angle, particularly near several critical angles.