The Distribution of Air-coupled Transducer Energy Among the Traveling Waves Excited in a Submerged Elastic Waveguide

Abstract

The distribution of the wave energy transmitted by a contactless ultrasonic piezoelectric transducer into the environment among the reflected, transmitted, and guided waves excited when sounding an immersed elastic plate is studied. The dependence of the time-averaged amount of wave energy transferred by each of the excited wave of different types (acoustic bulk waves, Lamb waves, and Scholte-Stoneley waves) on the relative source size, its distance to the plate, and frequency as well as a spatial structure of energy fluxes are analyzed. The numerical study is carried out in the framework of a semi-analytical model based on the integral and asymptotic representations for the Green function of the coupled problem under consideration. The plots of the wave energy dependence on the input parameters indicate the existence of local maxima (sweet spots) of the excited traveling waves that do not coincide with the maxima of the total source power.