Horizontal ducting of sound by curved nonlinear internal gravity waves in the continental shelf areas Journal Article


Authors: Lin, Y. T.; McMahon, K. G.; Lynch, J. F.; Siegmann, W. L.
Article Title: Horizontal ducting of sound by curved nonlinear internal gravity waves in the continental shelf areas
Abstract: The acoustic ducting effect by curved nonlinear gravity waves in shallow water is studied through idealized models in this paper. The internal wave ducts are three-dimensional, bounded vertically by the sea surface and bottom, and horizontally by aligned wavefronts. Both normal mode and parabolic equation methods are taken to analyze the ducted sound field. Two types of horizontal acoustic modes can be found in the curved internal wave duct. One is a whispering-gallery type formed by the sound energy trapped along the outer and concave boundary of the duct, and the other is a fully bouncing type due to continual reflections from boundaries in the duct. The ducting condition depends on both internal-wave and acoustic-source parameters, and a parametric study is conducted to derive a general pattern. The parabolic equation method provides full-field modeling of the sound field, so it includes other acoustic effects caused by internal waves, such as mode coupling/scattering and horizontal Lloyd#39;s mirror interference. Two examples are provided to present internal wave ducts with constant curvature and meandering wavefronts.
Journal Title: Journal of the Acoustical Society of America
Volume: 133
Issue: 1
ISSN: 0001-4966
Publisher: American Institute of Physics  
Publication Place: United States
Date Published: 2013
Start Page: 37
End Page: 49
Language: eng
DOI/URL:
Notes: JID: 7503051; ppublish