Excitation of Backward Ultrasonic Leaky Rayleigh and Leaky Lamb Waves

Abstract

It has been known for some time that bounded ultrasonic beam incident to a liquid-solid i nterface at the Rayleigh angle produces a complex reflected field. The field is produced by the interaction of the specularly reflected beam and the so-called l eaky Rayleigh waves propagating forward. Similar nonspecular effects are found at certain angles of incidence for liquid-solid-liq uid interfaces where leaky Lamb waves are generated in the forward direction. The purpose of this presentation is to report the g eneration o f the leaky Rayleigh and leaky Lamb waves in the backward direction. by the finite excitation of the interface and they are observed by the transmitting transducer in pulse-echo mode. leigh and leaky Lamb waves are obtained for the forward direction a lso received in the backward direction as well. Parameters affecting the amount of backscattered l eaky waves are: beam width, frequency, elastic properties of the solid and liquid and their densities. These backward leaky waves are produced