Development of a velocity gradient underwater acoustic intensity sensor

Abstract

A neutrally buoyant, underwater acoustic intensity probe is constructed and tested. This sensor measures the acoustic particle velocity at two closely spaced locations, hence it is denoted a ''u-u'' intensity probe. A new theoretical derivation infers the acoustic pressure from this one-dimensional velocity gradient, permitting the computation of one component of acoustic intensity. A calibration device, which produces a planar standing-wave field, is constructed and tested. In this calibrator, the performance of the u-u intensity probe compares favorably to that of an acoustic intensity probe which measures both pressure and velocity directly.

A comparison of two different sound intensity measurement principles

“…Some years ago a micromachined transducer called the "Microflown" became available for measurement of the acoustic particle velocity in air, 6 and an intensity probe based on this device in combination with a small pressure microphone is now in commercial production. 7,8 Yet another method based on determining the sound pressure from an approximation to the divergence of the particle velocity ͑the "u-u" method, which involves six velocity transducers͒ 9 has, to the authors' knowledge, never been used in air.…”

Direction finding using a biaxial particle-velocity sensor

“…Moreover, if these two uniaxial particle-velocity sensors are spatially displaced (as implemented in hardware in [6,9]) along any Cartesian axis (as), that displacement may have 3 possible orientations. Altogether, there are thus 3 Â 3 ¼ 9 possible configurations.…”

Design and implementation of a shielded underwater vector sensor for laboratory environments

“…[1][2][3][4][5] There are two main components to a p-a underwater vector sensor: a pressure sensor and a particle velocity sensor. A p-a probe with high acceleration sensitivity should be nearly neutrally buoyant in water.…”