Calculations of sound propagation through an eddy

Abstract

By means of a corrected split-step parabolic-equation numerical algorithm, acoustic propagation through an ocean region characterized by a sound-speed distribution produced by an analytic model of an eddy is investigated. Parameter values for a moderate sized, cyclonic, Gulf Stream eddy are used. It is found that the presence of an eddy causes significant changes, both in nature and level, in the received acoustic field produced by an omnidirectional cw source. The eddy causes major changes in the arrival structure seen by a vertical array. The percentage of energy arriving at angles less than 5° from broadside increases from 5% to 50% in the presence of the eddy under consideration at 100 Hz. Greatly increased energy corresponding to horizontal arrival is noted. In addition, the effects of an eddy progressing through the region between an acoustic source and receiver is studied. The position of the eddy relative to the source causes changes in transmission loss of as much as 20 dB.

Analysis the Influence of a Mesoscale Cold Eddy on Underwater Sound Propagation in the East of Luzon Strait

“…The 3D structures of eddies can be hardly determined, but are generally acquired by constructing ideal eddy structure models [1][2][3][4], the effects of eddies on sound propagation are analyzed together with sound propagation models. Also a few experiments have been conducted to investigate the effects of mesoscale eddies on sound propagation [5][6][7].…”

Sound propagation in a continuously stratified laboratory ocean model

“…1,2 Salinity, temperature, and hydrostatic pressure vary continuously with ocean depth, and the sound speed decreases with increasing depth until it reaches a minimum at a depth that is typically 1 km at mid-latitudes. The speed profile as a function of ocean depth is perturbed by spatiotemporal variations produced by internal gravity waves, [3][4][5] eddies, 6,7 and fronts. 8,9 Laboratory experiments have perturbed the sound speed using thermistors or acoustic lenses in tanks with a homogeneous fluid (e.g., Refs.…”

Influence of a Warm Eddy on Low-frequency Sound Propagation in the East Sea

“…국외 에서는 이미 오래전부터 수중음파 전파실험 및 수치모델 에 의해 소용돌이가 해수중 음파전파에 미치는 영향에 관 한 연구를 실시하고 있다. 특히 소용돌이가 빈번하게 발생 하는 것으로 알려져 있는 'Gulf Stream' 해역 (Baer 1980;Beckerle et al 1980;Mellberg et al 1990), 'Tasman Sea' 해역 (Nysen et al 1978;Lawrence 1983) 및 'East Greenland Sea' 해역 (Mellberg et al 1987 Fig. 7(a), Fig.…”