HYDROACOUSTICS
ANNUAL JOURNAL |
START | NEW VOL 20 | SEARCH | STATISTICS | PAS - GDANSK DIVISION |
pp. 209-216, vol. 14, 2011 Vladimir Shchurov V.I. Ilichev Pacific Oceanological Institute, Vladivostok, Russia Vladimir Kuleshov V.I. Ilichev Pacific Oceanological Institute, Vladivostok, Russia Alexis Cherkasov Adm. G.I. Nevelskoy Marine State University, Vladivostok, Russia Key words: sonogram; spectral density of acoustic pressure; histogram; Japanese Sea Abstract: The vortex structure of acoustic intensity vector in the shallow water depending on a distance and frequency emitting was researched basing on the natural in-situ experiment.
The experiment was fulfilled using the combined acoustic receivers in the Peter the Great Bay
in the Japanese Sea. When axes x and y of rectangular system of coordinates being located in
horizontal plane of the combined receiver, axis z was directed from surface to bottom. The
receiver was submerged to ~70 m depth at the site depth of ~120 m; sound velocity on the
surface was higher than that of the bottom’s one. To determine the vorticity there were
calculated three components of rotor of intensity vector then, their histograms of distribution
of probability density were plotted. In the work there were presented distribution histograms
of the vorticity probability density of intensity vector for 110 Hz frequency under the different
distances between source and receiver within ~1000–5000 m. In the case of single source the
highest density of probability corresponds to magnitude of ± 1 for x- and y- norm components
of rotor and 0 – magnitude for its z-component. As follows from the experiment the steady
vorticity of acoustic intensity vector was observed along the entire distance (~4000 m) from
source to receiver. The described mechanism of acoustic intensity transfer opens new
possibilities in the research of acoustic features in the shallow water. The fixed vortex
structures pose an interest as for physical acoustics, as for applied challenges of undersea
acoustics.
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