Free-Flooding Unidirectional Resonators for Deep-Ocean Transducers

An array of compound piezoceramic metal resonators can be made to radiate sound preferentially in one direction without auxiliary acoustic baffles if suitable geometries and material combinations are selected. This has the advantage that depth independence and high power-to-weight ratio are obtained. Expressions have been derived for the farfield front-to-back pressure ratio, the electromechanical coupling coefficient, and the mechanical Q for resonators with flared conical metal heads, cylindrical piezoceramic shanks, and tapered conical metal tails. The results of the analysis and supporting experimental work show that it is feasible to design practical, high-performance sound projectors for deep ocean operation attaining unidirectionality without the use of baffles.