Numerical simulation of the transient ultrasonic wave reflection at a liquid-solid interface
Résumé
In the nondestructive evaluation domain, the reflection of ultrasonic waves at liquid-solid interfaces generates interesting and useful phenomena when the incident angle approaches the longitudinal critical angle or Rayleigh angle. In this paper, we have developed a model for the study of the transient ultrasonic waves radiated by a plane or a focusing transducer in a liquid and reflected by a solid plane interface. The method used is an extension of the angular spectrum method to the transient case where the reflection at the plane interface is taken into account by using the reflection coefficient for plane harmonic waves.
The results obtained highlighted the different components of the ultrasonic field: the direct and edge waves as well as the longitudinal head waves or leaky Rayleigh waves. These waves have been carefully analyzed and discussed. Instantaneous cartographies allowed a clear description of all the waves which appear at the liquid-solid interface.