Abstract

We investigate the circumferential propagation of acoustic pulses in partially water-filled aluminum and stainless steel thin-walled cylindrical shells in the frequency x thickness (fd) region 0.64 MHz mm < fd < 0.96 MHz mm. In pulse-echo experiments, a multiplicity of periodic echoes were received when a single input pulse was applied to the outer surface of the shell. The periodic behaviour suggests that the pulses take different paths within the system, and that these paths depend upon the height of the liquid filler. Computer simulation and obstruction experiments are used to determine the nature of these paths, and identify, in particular, which modes propagate within the water-loaded portions of the shells. This work suggests that the A 0 Lamb-like wave predominates in the loaded shell. The application to liquid-level sensing is investigated.