Acoustic Properties of Sediments at Weapons Test Ranges of the Naval Undersea Warfare Engineering Station, Keyport, Washington

Download or read book Acoustic Properties of Sediments at Weapons Test Ranges of the Naval Undersea Warfare Engineering Station, Keyport, Washington written by and published by . This book was released on 1979 with total page 48 pages. Available in PDF, EPUB and Kindle. Book excerpt: Estimates are made of sound absorption and sound speed characteristics of sediments at the Dabob Bay and Keyport Shallow Water ranges operated by the Naval Undersea Warfare Engineering Station using empirical models developed by Hamilton and mean grain size and porosity data measured in samples collected by the authors. Data reported by earlier investigators permit estimates to be made also for sediments at the Nanoose and Jervis Inlet ranges. The purpose is to provide information which can be used in the design and evaluation of acoustic imaging devices which maybe able to ease the problems of locating and recovery of torpedoes which became buried in the sediments. Field and laboratory procedures are described. Also reported are the results of measured sound speeds in a number of the gravity core samples The most common surficial sediment is a soft, saturated silty-clay mud. For such sediments the sound absorption coefficient alpha in dB per meter should be given approximately by alpha = 0.1 where F is the sound frequency in kHz. It is concluded that sound absorption in these sediments, although not small, should not preclude the short range use of an acoustic imaging system operating at moderate frequencies. The possibility and the consequences of the existence of of gassy sediments is discussed.