Theoretical and experimental investigation of acoustic dyadic sensors

Abstract

The theoretical directivity index of a single combined acoustic receiver, a device that measures acoustic pressure, each component of particle velocity and velocity gradients at a collocated point, is presented. This receiver, described here as an acoustic dyadic sensor, is highly-directional, achieving as much as 9.5 dB of directivity gain. In practice, the higher-order velocity gradient components are obtained via a finite difference approximation of measured particle velocity. The statistical behavior of the errors in estimating the pure and mixed second-order partial derivatives are given. Experimental in-water measurements were completed on a prototype dyadic sensor, developed by EDO Corporation of Salt Lake City, Utah, and confirmed theoretical predictions.