Annular arrays for novel ultrasonic measurement techniques

Abstract. The paper shows how the precise knowledge of the sound field of an ultrasonic annular array can contribute to the development of novel measurement techniques. Emphasis is placed on (a) a non-invasive method for sound velocity measurements in fluids using the echo signals from scattering p]articles, (b) a non-invasive method for the combined determination of thickness and sound velocity in layered structures by using a novel focusing technique, and (c) a non-scanning curvature measurement method exploiting the wave front curvature of a reflected wave. To demonstrate the methods, the principles as well as results of simulations and measurements are discussed.