Low-frequency radiation characteristics of free-flooded ring transducers with application to a low-frequency directional hydrophone

Abstract

Numerically predicted radiation characteristics of uniformly vibrating free-flooded rings are compared with experiment at frequencies above the monopole region but still below any resonances. Low-frequency velocity distributions for piezoceramic rings for several commonly used drive conditions are derived. Analytical formulas for the monopole radiation resistance, farfield pressure, and free-field voltage sensitivity are presented. A technique is developed for measuring the piezoelectric constants of free-flooded ceramic cylinders. It is predicted and experimentally verified that a free-flooded circumferentially polarized ring has maximum sensitivity in the axial direction for a band of very low frequencies. Thus, such a system may have application as a low-frequency directional hydrophone.Subject Classification: 20.55.

Spherical Acoustic Broadband Receiver

“…j (b) V!po_ al[gp(l-r)/(l+r)] + gt + gt(l-r)} for exposed ends (5) ii where the first two terms are for the cylindrical surface and the third term is for the exposed end; Thus the free-field voltage sensitivity Mh…”