Resonance scattering of acoustic waves from cylindrical shells

The theory of resonance scattering, recently developed for acoustic‐wave scattering from elastic objects and elastic‐wave scattering from cavities, is applied here to the problem of sound scattering from fluid‐filled elastic cylindrical shells in a fluid, in particular air‐filled aluminum shells in water. The eigenvibrations of the shell appear as resonances in the scattering amplitude of each normal mode; these are superimposed on a smooth background which if the shell is made thinner, converts from the amplitude of a rigid to that of a soft cylinder. The resonances themselves are exhibited by subtracting the background from the total amplitude and are seen to become less numerous as the shell gets thinner.