Resonances in acoustic scattering from submerged curved elastic objects

The response of a submerged elastic body to an incident acoustic wave is usually represented as a series of normal modes. Each mode may resonate at a set of eigenfrequencies characteristic for that mode. It is shown that these resonances are caused by the coincidence of the phase velocities of the waves that form the standing-wave resonance, with that of any of the circumferential surface waves (Rayleigh, Stoneley, Whispering Gallery, or Franz waves) which constitute the diffracted field. Furthermore, the surface waves themselves are shown to undergo a resonance when satisfying the coincidence condition. Numerical examples for mode and surface wave resonances will be discussed.