Ultrasonic leaky waves in a solid plate separating a fluid and vacuum

Abstract

The reflection of a finite acoustic beam from a solid plate separating fluid and vacuum half-spaces has been measured and analyzed. Material viscous damping has been included in the reflection model and the finite beam has been approximated by an integral of the plane wave reflection coefficient times the spatial beam transform over the incident wave vector. The effects of viscosity and the finite beam on the reflected field are separately demonstrated, and generally good agreement is found between the model calculation and experiments on an aluminum plate with water chosen for the fluid. It is shown that the finite beam alone modified the plane-wave reflection coefficient substantially, whereas the introduction of viscosity exerts a smaller, but still important, influence.