INTERNAL WAVES: THEIR INFLUENCE UPON NAVAL OPERATIONS
ASW sonar technology rept.
LITTLE (ARTHUR D) INC CAMBRIDGE MA
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Internal waves, traveling beneath the ocean surface with maximum amplitude at or near the pycnocline, have been observed in various areas of the oceans. This report reviews what is known concerning the generation, prevalence, and characteristics of internal waves, and summarizes available knowledge concerning the effects of internal waves on naval operations. Internal waves affect naval operations in two principal areas--depth control and detection capability. The passage of large-amplitude internal waves could make submarine depth control difficult, particularly when the submarine is running quietly at low speed. Perturbations caused by the internal wave could initiate uncontrollable sinking of a submarine without power if the submarine were more compressible than sea water. The detection capabilities of ASW systems are influenced by internal waves because the latter affect transmission of acoustic signals through the ocean. The principal effect in deep water is a significant change in sonar range during the few hours required for the passage of high- amplitude internal wave. In coastal waters, the fluctuations in sonar signal due to short-period waves are of an appropriate frequency to interfere with target holding. It appears that the magnitude of the fluctuations in one-way transmission between source and target may be as high as 10 db.
- Physical and Dynamic Oceanography
- Undersea and Antisubmarine Warfare
- Fluid Mechanics