Echoes and helical surface waves on a finite elastic cylinder excited by sound pulses in water

Abstract

The echo responses of a finite elastic circular cylinder, excited by obliquely incident sound waves in water, are difficult to analyze by exact theory. In this paper, an approximate theoretical model based on reradiation of the elastic helical surface waves is presented. The basic expressions, suitable in a certain range of angles of incidence, are derived to estimate the time sequence of echo pulses and the resonance modes of the cylinder. Experimental results are shown, and are compared with the calculated results of the time sequence of echo pulses; both are found to be basically in agreement with each other.