Experiments and interpretation of surface waves acoustically generated on spherically endcapped cylindrical shells

Abstract

The impact of an acoustic pulse on a submerged elastic shell (which we shall assume evacuated) generates three types of circumferentially propagating surface waves: those that are analogous to plate waves of type A0(A1,A2,...) and S0(S1,S2,...), and a Scholte–Stoneley wave of type A that propagates in the surrounding fluid. A computer program devised by Hui Cao et al. renders visualizations of the generation and propagation of circumferential pulses on spherically endcapped shells, visualized by the re-radiation into the surrounding fluid of A, A0, and S0 waves in sequential pictures. These surface waves are generated experimentally by us in the laboratory from an ultrashort-pulse source, at axial incidence on a hemispherically endcapped glass tube. Sequential visualizations of the re-radiated pulses are obtained by using the Schardin–Cranz Schlieren method. These observations lead to an experimental measure of the group velocity dispersion curves of the surface waves.