Acoustic scattering from an air‐filled prolate cylinder

The ultrasonic scattering from circular cylinders is described in numerous papers. If the insonification is perpendicular to the cylinder axis, the scattering is strongly influenced by the propagation of circumferential waves. These circumferential waves propagate either in the elastic shell, where they are the Whispering Gallery waves, or at the interface water/elastic shell, where they are the Scholte‐Stoneley waves. These waves, for some frequencies called resonances, form standing waves around the cylinder. Previously, it has been shown that the resonance frequencies are functions of the cylinder diameter, the shell thickness, and the target composition. In this presentation, the influence of the curvature radius on the position and the amplitude of resonances is studied. The method of isolation and identification of resonances (MIIR) is used to plot resonance spectra of air‐filled prolate cylinders. The incident ultrasonic beam perpendicular to the cylinder axis insonifies the cross section at different positions. The resonance spectra of an air‐filled prolate cylinder are compared to those obtained with a circular cylinder that has the same thickness and the same circumference.