Design of an improved acoustic system for determination of the concentration of microbubbles in the ocean

Abstract

An acoustic system was designed to investigate microbubble concentrations and distributions in the ocean. The system consisted of a one-dimensional standing-wave resonator and a reverberation sensor. Concentrations are determined by measurement of the variation in system Q and the change in reverberation level produced by the resonant bubble response. The resonator and the sensor, while functioning independently, both measure bubble concentration as a function of depth and inferred size and thus provide a unique data comparison. The system has been designed to measure bubbles from approximately 700 microns to 30 microns utilizing frequencies from 5 tp 100 kHz at depths to 100 ft. Initial tests utilizing a bubble generator in an anechoic tank have demonstrated the system's capability to measure bubble concentrations.