DTIC ADA067386: Shallow Water Acoustic Studies pdf

DTIC ADA067386: Shallow Water Acoustic Studies

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In an attempt to formulate an accurate model for sound propagation in shallow water, several tests were conducted in Long Island Sound. A bottom-mounted projector, located off Block Island, and explosives were used as sources. A bottom-mounted hydrophone off Fishers Island and a hydrophone suspended over the side of a ship stationed near Watch Hill Point served as receivers. The latter hydrophone was used at three different depths. Propagation loss was measured over the two paths and plotted as a function of sea state. The results were compared with current shallow-water prediction equations. Data obtained during the winter agreed fairly well, while data obtained during the spring showed considerably higher loss than predicted. This discrepancy is attributed to the many more bottom bounces than predicted by the shallow-water formulas. A plot of propagation loss as a function of frequency for explosive sources showed a minimum at 140 Hz.

Missilyzer analysis of the same data indicated that the lowest normal mode predominates in this channel. This conclusion was borne out by an analysis of propagation loss curves for different receiving depths. (Author

• Creator/s: Defense Technical Information Center
• Date: 11/27/1968
• Year: 1968
• Book Topics/Themes: DTIC Archive, Sussman, Bernard, NAVY UNDERWATER SOUND LAB NEW LONDON CONN, *SHALLOW WATER, *WAVE PROPAGATION, *UNDERWATER ACOUSTICS, UNDERSEA WARFARE, NAVAL RESEARCH, WIND VELOCITY, HYDROPHONES, SEA STATES, OCEAN MODELS, SONAR, UNDERWATER SOUND

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