Sonic Booms in the Sea

Sonic Booms in the Sea PDF

Author: Robert J Urick

Publisher:

Published: 1971

Total Pages: 32

ISBN-13:

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Sonic booms laid down by Navy fighter aircraft flying at Mach 1.1-1.2 have been observed below the surface of the sea by means of a string of hydrophones 195 feet long dangling from a surface ship. The underwater booms were found to decay about as the -3/2 power of the depth below the surface, to have the same spectral content as the boom in air, and to travel down the string with the velocity of sound in water. These findings contradict the theory of an 'inhomogeneous' wave incident beyond the critical angle, as originally stated by Rayleigh and as recently extended to sonic booms by Sawyers and Cook. They suggest, instead, that the underwater sonic boom is a wave scattered by the rough sea surface into the sea below. Its decay with depth is so rapid that it is not likely to be perceptible against the ambient noise background at depths greater than one or two thousand feet in the deep sea. (Author).

High-Speed Dreams

High-Speed Dreams PDF

Author: Erik M. Conway

Publisher: JHU Press

Published: 2008-11-03

Total Pages: 404

ISBN-13: 1421410435

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In High-Speed Dreams, Erik M. Conway constructs an insightful history that focuses primarily on the political and commercial factors responsible for the rise and fall of American supersonic transport research programs. Conway charts commercial supersonic research efforts through the changing relationships between international and domestic politicians, military/NASA contractors, private investors, and environmentalists. He documents post-World War II efforts at the National Advisory Committee on Aeronautics and the Defense Department to generate supersonic flight technologies, the attempts to commercialize these technologies by Britain and the United States during the 1950s and 1960s, environmental campaigns against SST technology in the 1970s, and subsequent attempts to revitalize supersonic technology at the end of the century. High-Speed Dreams is a sophisticated study of politics, economics, nationalism, and the global pursuit of progress. Historians, along with participants in current aerospace research programs, will gain valuable perspective on the interaction of politics and technology.

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