Mini-sparker application to hydrophones calibration and diffraction investigation

A transient sound source based on an underwater spark discharge, has been developed for acoustic impulse phenomenon studies. The emitted wave is omnidirective and presents a very short and simple signature resulting from its broadband frequency characteristics. Two specific applications are presented: hydrophone impulse response measurement, first, and study of diffraction by a glass sphere immersed in water, secondly. In this last application, high speed cinematography (1 Million frames/sec), based on the shadowgraph technique, has been used for the interpretation of the different diffracted waves