Modelling of pulse-echo scattering using a water-coupled transducer

This paper outlines some new developments in the modelling of a commonly found industrial situation where a water-coupled transducer is used to interrogate defects in a solid. The echo signals recorded back at the transducer need to be interpreted (or inverted) in order to characterise those defects. In particular we will look at the new finite-difference modelling of this problem, and show that it allows very accurate predictions to be made of signals from known defects. We will also consider other approaches that give insight into the physical processes involved in the wave scattering and echo formation. In time these methods-taken together-could lead to an accurate inversion procedure for this problem for a wide range of defects