mirage

A modeling study of acoustic propagation through moving shallow-water solitary wave packets

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dc.contributor.author Duda, Timothy F.
dc.contributor.author Preisig, James C.
dc.date.accessioned 2011-12-13T15:40:21Z
dc.date.available 2011-12-13T15:40:21Z
dc.date.issued 1999-01
dc.identifier.citation IEEE Journal of Oceanic Engineering 24 (1999): 16-32 en_US
dc.identifier.uri http://hdl.handle.net/1912/4932
dc.description Author Posting. © IEEE, 1999. This article is posted here by permission of IEEE for personal use, not for redistribution. The definitive version was published in IEEE Journal of Oceanic Engineering 24 (1999): 16-32, doi:10.1109/48.740153. en_US
dc.description.abstract Propagation of 400-Hz sound through continental-shelf internal solitary wave packets is shown by numerical simulation to be strongly influenced by coupling of normal modes. Coupling in a packet is controlled by the mode coefficients at the point where sound enters the packet, the dimensions of the waves and packet, and the ambient depth structures of temperature and salinity. In the case of a moving packet, changes of phases of the incident modes with respect to each other dominate over the other factors, altering the coupling over time and thus inducing signal fluctuations. The phasing within a moving packet varies with time scales of minutes, causing coupling and signal fluctuations with comparable time scales. The directionality of energy flux between high-order acoustic modes and (less attenuated) low-order modes determines a gain factor for long-range propagation. A significant finding is that energy flux toward low-order modes through the effect of a packet near a source favoring high-order modes will give net amplification at distant ranges. Conversely, a packet far from a source sends energy into otherwise quiet higher modes. The intermittency of the coupling and of high-mode attenuation via bottom interaction means that signal energy fluctuations and modal diversity fluctuations at a distant receiver are complementary, with energy fluctuations suggesting a source-region packet and mode fluctuations suggesting a receiver-region packet. Simulations entailing 33-km propagation are used in the analyses, imitating the SWARM experiment geometry, allowing comparison with observations en_US
dc.description.sponsorship This work was supported by the Office of Naval Research under Grant N00014-95-1- 0029 and Grant N00014-95-1-0051. en_US
dc.format.mimetype application/pdf
dc.language.iso en_US en_US
dc.publisher IEEE en_US
dc.relation.uri http://dx.doi.org/10.1109/48.740153
dc.subject Coupled mode analysis en_US
dc.subject Underwater acoustic propagation en_US
dc.subject Underwater acoustics en_US
dc.title A modeling study of acoustic propagation through moving shallow-water solitary wave packets en_US
dc.type Article en_US
dc.identifier.doi 10.1109/48.740153


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