Transmission of Sound Through a Randomly Rough Air-Sea Interface
Transmission of Sound Through a Randomly Rough Air-Sea Interface

Author: James Dixon Hagy (Jr)

Publisher:

Published: 1970

Total Pages: 129

ISBN-13:

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The Helmholtz integral and the Kirchhoff approximation have been used to develop predictions for the transmission of sound through a rough air-sea interface. A model study was conducted with wind-driven surfaces generated in a large anechoic tank. The frequencies used were scaled to be equivalent to low audio frequencies with moderate seas. The coherent component of the transmitted acoustic intensity was tested for exponential decrease with increasing values of the roughness parameter. An empirical correction factor was determined to give a corrected roughness. (Author).

Frequency Dependence of Sound Transmitted from an Airborne Source Into the Ocean
Frequency Dependence of Sound Transmitted from an Airborne Source Into the Ocean

Author: Herman Medwin

Publisher:

Published: 1972

Total Pages: 70

ISBN-13:

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The predicted dependence of sound transmission on the statistics of the randomly-rough interface between dissimilar fluids has been studied by use of the Helmholtz Integral. The predictions have been verified for radiation from a helicopter hovering, and slowly moving, over the sea, for frequencies to 1000 Hz for a wide range of slowly moving, over the sea, for frequencies to 1000 Hz for a wide range of surface acoustical roughnesses. The roughness parameters are the rms height of the surface, propagation constant, speed of propagation and angle with the normal, respectively. The transmission change of sound pressure as a function of frequency is presented for several conditions of an SH3-D helicopter hovering and flying over or near an array of microphone and sonobuoy hydrophones. (Author)

Sounds in the Sea
Sounds in the Sea

Author: Herman Medwin

Publisher: Cambridge University Press

Published: 2005-07-21

Total Pages: 682

ISBN-13: 9780521829502

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Fundamentals of Acoustical Oceanography
Fundamentals of Acoustical Oceanography

Author: Herman Medwin

Publisher: Academic Press

Published: 1997-11-05

Total Pages: 739

ISBN-13: 0080532160

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The developments in the field of ocean acoustics over recent years make this book an important reference for specialists in acoustics, oceanography, marine biology, and related fields. Fundamentals of Acoustical Oceanography also encourages a new generation of scientists, engineers, and entrepreneurs to apply the modern methods of acoustical physics to probe the unknown sea. The book is an authoritative, modern text with examples and exercises. It contains techniques to solve the direct problems, solutions of inverse problems, and an extensive bibliography from the earliest use of sound in the sea to present references.Written by internationally recognized scientists, the book provides background to measure ocean parameters and processes, find life and objects in the sea, communicate underwater, and survey the boundaries of the sea. Fundamentals of Acoustical Oceanography explains principles of underwater sound propagation, and describes how both actively probing sonars and passively listening hydrophones can reveal what the eye cannot see over vast ranges of the turbid ocean. This book demonstrates how to use acoustical remote sensing, variations in sound transmission, in situ acoustical measurements, and computer and laboratory models to identify the physical and biological parameters and processes in the sea.* Offers an integrated, modern approach to passive and active underwater acoustics* Contains many examples of laboratory scale models of ocean-acoustic environments, as well as descriptions of experiments at sea* Covers remote sensing of marine life and the seafloor* Includes signal processing of ocean sounds, physical and biological noises at sea, and inversions* resents sound sources, receivers, and calibration* Explains high intensities; explosive waves, parametric sources, cavitation, shock waves, and streaming* Covers microbubbles from breaking waves, rainfall, dispersion, and attenuation* Describes sound propagation along ray paths and caustics* Presents sound transmissions and normal mode methods in ocean waveguides

Underwater Medicine and Related Sciences
Underwater Medicine and Related Sciences

Author: Charles Wesley Shilling

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 704

ISBN-13: 1468485008

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This volume follows and updates AN ANNOTATED BIBLIOGRAPHY ON DIVING AND SUBMARINE MEDICINE published by Gordon and Breach, Science Publishers, Inc., in 1971. The time period covered is primarily the calendar years 1970 and 1971. Also included, however, is much material from the calendar years 1968 and 1969 not in the previous publication. A brief analysis of the sources of material precedes the citations and abstracts, which comprise the main section of the volume. The bibliography is followed by a permuted subject index and an author index. Also included, following the indexes, is a micro thesaurus. Although no attempt has been made to do a critical subject analysis, such an analysis could be accomplished through selecting a particular subject, looking up the appropriate key works in the rotated index, identifying the abstracts, analyzing them, obtaining complete copy as desired, and completing the critical review. David C. Weeks, Ph.D. Director, BSCP Washington, D.C.

The Transmission of Sound Through a Stochastic Interface
The Transmission of Sound Through a Stochastic Interface

Author: John Carter Calhoun

Publisher:

Published: 1971

Total Pages: 193

ISBN-13:

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The problem of sound transmission through a stochastic interface was investigated using a surface model which employed two scales of roughness. The theory was developed for application to the problem of sound transmission from air to water at the ocean surface. A perturbation method was applied to obtain the local surface values of the pressure and the normal derivative of the pressure at the stochastic interface for use in the Kirchhoff integral. Two different correlation function models were employed, one corresponding to isotropic surface roughness, with the other corresponding to anisotropic surface roughness. The isotropic model revealed the general behavior of the effect of the large scale roughness on the mean square pressure as a function of position and frequency but failed to indicate the effect of the small scale roughenss. In addition, the effect of change in wind speed was not observed. The anisotropic model a similar general behavior for the effect of the large scale roughness and, in addition, indicated the effect of the small scale roughness and the variation with change in wind speed. (Author Modified Abstract).