Abstract
Sound signals propagation in a shallow-water area with bowl-like bottom relief which can be part of an underwater canyon, a bay, a lagoon or a lake is studied. Such area is characterized by curvilinear (in particular circular) isobaths with the depth increasing towards their center of curvature (inner part of the bowl). Manifestation of horizontal refraction in this case consists in the existence of whispering gallery waves (WGWs) localized in some vicinity of isobaths. Main attention is paid to conditions and criteria of excitation of such waves by a point source and specific features of their propagation. It is shown that WGWs can be excited by a source localized both inside the area with bowl-like bathymetry and in its exterior. The latter case can take place due to the “tunneling” of sound wave to the inner part of the bowl from the exterior. Efficiency of the tunneling is estimated for realistic waveguide models. The amplitude of excited WGWs depends on the sound frequency, on the position of the source and parameters of the waveguide, in particular, on the curvature radius of isobaths. Modal structure of whispering gallery beam is analyzed both in an analytical form and using numerical modeling within the framework of Parabolic Equation approach. The respective azimuthal wavenumbers and radial mode functions are computed. Dispersion of such waves is also investigated, and the possibility of their experimental observation is discussed.. [This work was supported by Israel Science Foundation, grant 565/15].
Original language | English |
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Pages (from-to) | 723-726 |
Number of pages | 4 |
Journal | Underwater Acoustic Conference and Exhibition Series |
State | Published - 2019 |
Event | 5th Underwater Acoustics Conference and Exhibition, UACE 2019 - Hersonissos, Greece Duration: 30 Jun 2019 → 5 Jul 2019 |
Bibliographical note
Publisher Copyright:© 2019, I.A.C.M, Foundation for Research and Technology - Hellas. All rights reserved.
Keywords
- horizontal refraction
- shallow water acoustics
- whispering gallery
ASJC Scopus subject areas
- Geophysics
- Oceanography
- Environmental Engineering
- Acoustics and Ultrasonics