Frequency derivative approach for identification of the wave resonances on immersed elastic bodies

Acoustic scattering by elastic bodies is usually analyzed in terms of resonances, the frequency, width, and order of which should be determined. In this paper, a simple approach based on a frequency derivative of the scattered pressure is proposed for resonance order identification on bodies of arbitrary shape. The method is applied to the acoustic scattering of a plane wave by a spherical shell for validation and by a cylindrical shell bounded by hemispherical end caps. In both cases, the A and S0 wave resonances are identified.