Local Field of an Acoustic Source in a Submarine Canyon

Abstract

An exploratory study is presented concerning hydroacoustic signal reception in the locale of a single-frequency CW ultrasonic source situated within an underwater submarine canyon. A first-order laboratory model of a submarine canyon is described together with the hydroacoustic studies that have been made with the simulation setup. For each of several transmitter positions within the canyon, ultrasonic reception has been recorded continuously in (transmitter-to-receiver) range for a variety of orientations and depths of receiver relative to transmitter. Although canyon geometry was arranged to be readily changeable, only canyon width has been varied thus far. Some broad inferences from our study are: (1) a submarine canyon can behave as a waveguide and channel sound almost undiminished for some distance down the canyon, both within and above its confines; (2) the canyon can act as an acoustic horn relative to sound radiation immediately above its confines; and 3) sound reception beyond the locale of the canyon can be appreciably smaller than that realized in the absence of the canyon. Quantitative results depend on the transmitter position within the canyon, canyon geometry and topography, the nature of the sound source, and the relative location of the receiver.