Accession Number : ADA263197


Title :   The Influence of a Bubbly Layer on Near-Surface Acoustic Propagation and Surface Loss Modeling


Descriptive Note : Technical rept.


Corporate Author : NAVAL UNDERSEA WARFARE CENTER NEWPORT DIV NEW LONDON CT NEW LONDON DETACHMENT


Personal Author(s) : Christian, Raymond J


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a263197.pdf


Report Date : 11 Dec 1992


Pagination or Media Count : 23


Abstract : The impact of refraction, attenuation, and scattering due to a near- surface bubbly layer on acoustic propagation modeling can be significant in sensitive surface duct and shallow water environments. Hall (J. Acoustic. Soc. Am. 86(3), September 1989) presents a semi-empirical acoustic model to determine the propagation effects of the bubbly layer on one-way horizontal transmission in a surface duct. Expressions for the depth-dependent complex sound speed and attenuation are used to extend the Hall model to the general near-surface acoustic interaction problem. The rough surface scattering at the air-sea interface and the propagation through the subsurface bubbly layer are treated independently in a simplified approach toward examining the impact of bubbles on modeled surface duct and shallow water transmission loss. The dependence of the 'effective' surface loss on grazing angle and wind speed is analyzed in the frequency band of approximately 0.5-5 kHz.... Attenuation, Damping, Shallow water, Bubbles, Grazing angle, Surface duct, Bubbly layer, Refraction, Surface loss.


Descriptors :   *ACOUSTIC WAVES , *WAVE PROPAGATION , *BUBBLES , *AIR WATER INTERACTIONS , ANGLES , SCATTERING , OCEAN SURFACE , WIND , DEPTH , SOUND , SUBSURFACE , ACOUSTIC VELOCITY , AMBIENT NOISE , ACOUSTIC SCATTERING , REFRACTION , ACOUSTIC ATTENUATION , ACOUSTICS , WIND VELOCITY , ATTENUATION , GRAZING , ACOUSTIC REFRACTION , TRANSMISSION LOSS , SHALLOW WATER , FREQUENCY BANDS , SURFACES , DAMPING , MODELS , INTERFACES , LAYERS


Subject Categories : Acoustics
      Fluid Mechanics


Distribution Statement : APPROVED FOR PUBLIC RELEASE