Ocean And Seabed Acoustics

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Ocean And Seabed Acoustics

Author : George V. Frisk
ISBN : 9780132441544
Genre : Technology & Engineering
File Size : 57.72 MB
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Respected scientist and educator George V. Frisk draws on his extensive professional experience to demonstrate how the ocean environment provides an excellent setting in which to display general principles of wave propagation that are also applicable to other areas of wave physics. Ocean and Seabed Acoustics proceeds with a derivation of elementary solutions to the wave equation in free space and then progressively addresses problems of increasing complexity. This book concludes with a discussion of acoustic wave propagation due to a point source in an inhomogeneous waveguide with lossy boundaries.
Category: Technology & Engineering

Acoustics Of The Seabed As A Poroelastic Medium

Author : Nicholas P. Chotiros
ISBN : 9783319142777
Genre : Science
File Size : 51.76 MB
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This book presents a concise description of the acoustics of ocean sediment acoustics, including the latest developments that address the discrepancies between theoretical models and experimental measurements. This work should be of interest to ocean acoustic engineers and physicists, as well as graduate students and course instructors. The seabed is neither a liquid nor a solid, but a fluid saturated porous material that obeys the wave equations of a poroelastic medium, which are significantly more complicated than the equations of either a liquid or a solid. This volume presents a model of seabed acoustics with input parameters that allow the model to cover a wide range of sediment types. The author includes example reflection and transmission curves which may be used as typical for a range of sediment types. The contents of this book will allow the reader to understand the physical processes involved in the reflection, propagation, and attenuation of sound and shear waves in ocean sediments and to model the acoustic properties for a wide range of applications.
Category: Science

Ocean Seismo Acoustics

Author : T. Akal
ISBN : 9781461322016
Genre : Science
File Size : 85.59 MB
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Seafloor investigation has long been a feature of not only seismology but also of acoustics. Indeed it was acoustics that produced depth sounders, giving us the first capability of producing both global and local maps of the seafloor. Subsequently, better instrumentation and techniques led to a clearer, more quantitative picture of the seabed itself, which stimulated new hypotheses such as seafloor spreading through the availability of more reliable data on sediment thickness over ocean basins and other bottom features. Geologists and geophysicists have used both acoustic and seismic methods to study the seabed by considering the propagation of signals arising from both natural seismic events and man-made impulsive sources. Although significant advances have been made in instrumentation, such as long towed geophysical arrays, ai r guns and ocean bot tom seismometers, the pic ture of the seafloor is still far from complete. Underwater acoustics concerns itself today with the phenomena of propagation and noise at frequencies and ranges that require an understanding of acoustic interaction at both of its boundaries, the sea surface and seafloor, over depths ranging from tens to thousands of meters. Much of the earlier higher frequency (>1 kHz) work included the characterization of the seafloor in regimes of reflection coefficients which were empirically derived from surveys. The results of these studies met with only limited success, confined as they were to those areas where survey data existed and lacking a physical understanding of the processes of reflection and scattering.
Category: Science

Bottom Interacting Ocean Acoustics

Author : William A. Kuperman
ISBN : 9781468490510
Genre : Science
File Size : 68.17 MB
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vi These categories seem to represent the basic breakdown by field of present-day research in this area. Though each paper has been classified into one of these categories (for conference organization purpose), many papers overlapped two or three areas. It is also interesting to note that not only are scientific results being communicated, but the latest techniques and the state-of-the-art tools of the trade (existing and in development) are also being presented. The forty-six papers presented at this conference represent the work of seventy scientists working at universities, government laboratories, and industrial laboratories in seven different countries . We would like to thank the contributors for their efforts and especially for their promptness in providing the editors with their final manuscripts. William A. Kuperman Finn B. Jensen La Spezia, Italy July 1980 CONTENTS GEOACOUSTIC PROPERTIES OF MARINE SEDIMENTS Attenuation of Sound in Marine Sediments . • 1 J. M. Hovem Directivity and Radiation Impedance of a Transducer 15 Embedded in a Lossy Medium . •• •••••• G. H. Ziehm Elastic Properties Related to Depth of Burial, Strontium Content and Age, and Diagenetic Stage in Pelagic Carbonate Sediments . . • • . • • • . 41 M. H. Manghnani, S. O. Schianger, and P. D. Milholland Application of Geophysical Methods 'and Equipment to Explore the Sea Bottom . •• •••. • 53 H. F. Weichart The Acoustic Response of Some Gas-Charged Sediments in the Northern Adriatic Sea • • • • . • • • • 73 A.
Category: Science

Full Field Inversion Methods In Ocean And Seismo Acoustics

Author : Orest Diachok
ISBN : 9789401584760
Genre : Technology & Engineering
File Size : 50.59 MB
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Recent advances in the power of inversion methods, the accuracy of acoustic field prediction codes, and the speed of digital computers have made the full field inversion of ocean and seismic parameters on a large scale a practical possibility. These methods exploit amplitude and phase information detected on hydrophone/geophone arrays, thereby extending traditional inversion schemes based on time of flight measurements. Full field inversion methods provide environmental information by minimising the mismatch between measured and predicted acoustic fields through a global search of possible environmental parameters. Full Field Inversion Methods in Ocean and Seismo-Acoustics is the formal record of a conference held in Italy in June 1994, sponsored by NATO SACLANT Undersea Research Centre. It includes papers by NATO specialists and others. Topics covered include: · speed and accuracy of acoustic field prediction codes · signal processing strategies · global inversion algorithms · search spaces of environmental parameters · environmental stochastic limitations · special purpose computer architectures · measurement geometries · source and receiving sensor technologies.
Category: Technology & Engineering

Sounds In The Sea

Author : Herman Medwin
ISBN : 052182950X
Genre : Science
File Size : 81.53 MB
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Underwater acousticians and acoustical oceanographers use sound as the premier tool to determine the detailed characteristics of physical and biological bodies and processes at sea. Sounds in the Sea is a comprehensive and accessible textbook on ocean acoustics and acoustical oceanography. The first nine chapters provide the basic tools of ocean acoustics. The following fifteen chapters are written by many of the world's most successful ocean researchers. These chapters describe modern developments, and are divided into four sections: Studies of the Near Surface Ocean; Bioacoustical Studies; Studies of Ocean Dynamics; and Studies of the Ocean Bottom. This is an invaluable textbook for any course in ocean acoustics for the physical and biological ocean sciences, and engineering. It will also serve as a reference for researchers and professionals in ocean acoustics, and an excellent introduction to the topic for scientists from related fields.
Category: Science

Progress In Underwater Acoustics

Author : Harold Merklinger
ISBN : 9781461318712
Genre : Technology & Engineering
File Size : 69.24 MB
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IMAGE TRACKS AT HALIFAX by L.B. Felsen All living kind much effort spend Some model modes, some model rays, To cope with their environment Some feel that spectra all portrays. Some use their eyes, some use their nose Then there are those who with despatch, To sense where other things repose. Take refuge in the ocean wedge. For one group, nothing's more profound Than to explore the world with sound. If things get messy, randomize. These audio diagnosticians What's partly smooth, determinize. You ponder, is it this or that? Go by the name of acousticians. And wish you were a lowly bat They regularly meet to check Whether their sonogram's on track. The meeting's hosts did treat us well. With images stored in their packs, They let the climate cast its spell. This year they came to Halifax. No weath'ry hope was placed in vain. There they combined with ocean types We were exposed to wind and rain, And each could hear the other's gripes. We glimpsed blue sky through clouds dispersed. A meeting naturally does start But rainy sequence was reversed: Reviewing present state of art. The ocean types would like it wet What we found out is where it's at: Yet they got stuck with sun instead. We cannot hope to match the bat Each confrence has the same refrain: Computer printouts by the reams It has been fun to meet again.
Category: Technology & Engineering

Buried Waste In The Seabed Acoustic Imaging And Bio Toxicity

Author : Philippe Blondel
ISBN : 9783540281214
Genre : Science
File Size : 35.92 MB
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Buried waste on the seabed is a major source of pollution. But, very often, waste sites are not known until a serious problem occurs, or are not adequately mapped. Recent examples around Europe include WWI and WWII ammunition dump sites (e.g. Beufort Dyke in the UK), dumped nuclear submarines in the Arctic Seas, clandestine or hidden toxic-waste in the Baltic Sea and the North Sea. Even if properly documented, waste sites evolve with time (dumped material can move with currents and tides, especially on a scale of decades; toxic-material barrels can corrode and leak). This book shows the results of a concerted EU-funded effort to tackle this problem and find innovative ways to identify and map toxic waste sites on the seabed, whether they have been covered with sediments or not. These results are applicable to any region on the seabed in the entire world.
Category: Science

Acoustic Signal Processing For Ocean Exploration

Author : J.M.F Moura
ISBN : 9789401116046
Genre : Technology & Engineering
File Size : 52.84 MB
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Acoustic Signal Processing for Ocean Explortion has two major goals: (i) to present signal processing algorithms that take into account the models of acoustic propagation in the ocean and; (ii) to give a perspective of the broad set of techniques, problems, and applications arising in ocean exploration. The book discusses related issues and problems focused in model based acoustic signal processing methods. Besides addressing the problem of the propagation of acoustics in the ocean, it presents relevant acoustic signal processing methods like matched field processing, array processing, and localization and detection techniques. These more traditional contexts are herein enlarged to include imaging and mapping, and new signal representation models like time/frequency and wavelet transforms. Several applied aspects of these topics, such as the application of acoustics to fisheries, sea floor swath mapping by swath bathymetry and side scan sonar, autonomous underwater vehicles and communications in underwater are also considered.
Category: Technology & Engineering

Acoustic Investigation Of Complex Seabeds

Author : Jacques Yves Guigné
ISBN : 9783319025797
Genre : Science
File Size : 32.99 MB
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Offshore drilling and constructions require exact knowledge of the geophysical properties of the seabed and sub-seabed, as unexpected objects can slow down or halt projects. This book presents the state-of-the-art in acoustic exploration of the seabed and sub-seabed, from initial designs in the 1980s to commercial contracting and operation of the Acoustic CorerTM in the last decade. The Acoustic CorerTM is a high-definition commercial acoustic sub-bottom imaging system, producing an “acoustic core” within which sub-seabed sedimentary characteristics and discrete buried objects larger than 0.5 m can be identified and mapped. It makes use of the innovative JYG-cross design, inspired by seismic reflection and uses Synthetic Aperture Sonar (SAS) multi-angle scattering in and within the seabed to deliver unprecedented imagery. This book was written by the inventor of these concepts, a known specialist in seabed acoustics, with help from an experienced academic and author. It is intended first and foremost as a “how-to” guide for offshore industries looking at techniques to make the installation of different types of structures safe and efficient.
Category: Science

Marine Acoustics

Author : James L. Buchanan
ISBN : 9780898715477
Genre : Science
File Size : 55.49 MB
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Marine Acoustics: Direct and Inverse Problems presents current research trends in the field of underwater acoustic wave direct and inverse problems. It is the first to investigate inverse problems in an ocean environment, with heavy emphasis on the description and resolution of the forward scattering problem.
Category: Science

Inverse Problems In Underwater Acoustics

Author : Michael I. Taroudakis
ISBN : 0387952489
Genre : Mathematics
File Size : 25.63 MB
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This volume provides recent and useful results for bottom recognition, inverse scattering in acoustic wave guides and ocean acoustic tomography, plus a discussion of some of the new algorithms, such as those related to matched-field processing, which have recently been used for inverting experimental data.
Category: Mathematics

Fundamentals Of Shallow Water Acoustics

Author : Boris Katsnelson
ISBN : 9781441997760
Genre : Science
File Size : 47.63 MB
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Shallow water acoustics (SWA), the study of how low and medium frequency sound propagates and scatters on the continental shelves of the worlds oceans, has both technical interest and a large number of practical applications. Technically, shallow water poses an interesting medium for the study of acoustic scattering, inverse theory, and propagation physics in a complicated oceanic waveguide. Practically, shallow water acoustics has interest for geophysical exploration, marine mammal studies, and naval applications. Additionally, one notes the very interdisciplinary nature of shallow water acoustics, including acoustical physics, physical oceanography, marine geology, and marine biology. In this specialized volume the authors, all of whom have extensive at-sea experience in US and Russian research efforts, have tried to summarize the main experimental, theoretical, and computational results in shallow water acoustics, with an emphasis on providing physical insight into the topics presented.
Category: Science

An Introduction To Underwater Acoustics

Author : Xavier Lurton
ISBN : 3540429670
Genre : Science
File Size : 28.8 MB
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Presented in a clear and concise way as an introductory text and practical handbook, the book provides the basic physical phenomena governing underwater acoustical waves, propagation, reflection, target backscattering and noise. It covers the general features of sonar systems, transducers and arrays, signal processing and performance evaluation. It provides an overview of today's applications, presenting the working principles of the various systems. From the reviews: "Presented in a clear and concise way as an introductory text and practical handbook, the book provides the basic physical phenomena governing underwater acoustical waves, propagation, reflection, target backscattering and noise. ⦠It provides an overview of todayâs applications, presenting the working principles of the various systems." (Oceanis, Vol. 27 (3-4), 2003) "This book is a general survey of Underwater Acoustics, intended to make the subject âas easily accessible as possible, with a clear emphasis on applications.â In this the author has succeeded, with a wide variety of subjects presented with minimal derivation ⦠. There is an emphasis on technology and on intuitive physical explanation ⦠." (Darrell R. Jackson, Journal of the Acoustic Society of America, Vol. 115 (2), February, 2004) "This is an exciting new scientific publication. It is timely and welcome ⦠. Furthermore, it is up to date and readable. It is well researched, excellently published and ranks with earlier books in this discipline ⦠. Many persons in the marine science field including acousticians, hydrographers, oceanographers, fisheries scientists, engineers, educators, students ⦠and equipment manufacturers will benefit greatly by reading all or part of this text. The author is to be congratulated on his fine contribution ⦠." (Stephen B. MacPhee, International Hydrographic Review, Vol. 4 (2), 2003)
Category: Science

Computational Ocean Acoustics

Author : Finn B. Jensen
ISBN : 1563962098
Genre : Science
File Size : 50.96 MB
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"Many practical suggestions and tips; the examples are meaningful and the illustrations are effective....Destined to become a classic reference that any serious practitioner of ocean acoustics cannot afford to ignore." Revue de livre Authored by four internationally renowned scientists, this volume covers 20 years of progress in computational ocean acoustics and presents the latest numerical techniques used in solving the wave equation in heterogeneous fluid-solid media. The authors detail various computational schemes and illustrate many of the fundamental propagation features via 2-D color displays.
Category: Science

Geoacoustic Inversion In Laterally Varying Shallow Water Experiments Using High Resolution Wavenumber Estimation

Author : Kyle M. Becker
ISBN : UCSD:31822032643611
Genre : High resolution spectroscopy
File Size : 48.25 MB
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(Cont.) The estimator was also applied to determine wavenumbers for synthetic data where the water column sound speed contained temporal variations due to the presence of internal waves. It was shown that reliable estimates of horizontal wavenumbers could be obtained that are consistent with the boundary conditions of the waveguide. The Modal Mapping Experiment (MOMAX), an experimental method for measuring the full spatial variability of a propagating sound field and its corresponding modal content in two-dimensions, is also discussed. The AR estimator is applied to extract modal content from the real data and interpreted with respect to source/receiver motion and geometry. For a moving source, it is shown that the wavenumber content is Doppler shifted. A method is then described that allows the direct measure of modal group velocities from Doppler shifted wavenumber spectra. Finally, numerical studies are presented addressing the practical issues associated with using MOMAX type data in the exact inversion method of Gelfand-Levitan.
Category: High resolution spectroscopy

Impact Of Littoral Environmental Variability On Acoustic Predictions And Sonar Performance

Author : N. G. Pace
ISBN : 1402008163
Genre : Science
File Size : 37.41 MB
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The limiting influence of the environment on sonar has long been recognised as a major challenge to science and technology. As the area of interest shifts towards the littoral, environmental influences become dominant both in time and space. The manifold challenges encompass prediction, measurement, assessment, and adaptive responses to maximize the effectiveness of systems. Although MCM and ASW activities are dominated in different ways and scales by the environment, both warfare areas have had to consider the significantly changing requirements posed by operations in the littoral. The fundamental scientific issues involved in developing models relating acoustics to the environment are matched in difficulty by the need for data for their validation and eventual practical use for prediction. In many instances the need is for the longer term planning activities. This book and the enclosed CD-ROM are the proceedings of a conference organised by the SACLANT Undersea Research Centre, and held at the Villa Marigola, Lerici, Italy, on 16-20 September 2002. CD-ROM Included: This volume contains a CD-ROM which in addition to an electronically searchable version of the proceedings, has full colour versions of figures which are printed in black and white in the book.
Category: Science

Underwater Acoustic Modeling And Simulation

Author : Paul C. Etter
ISBN : 9781466564947
Genre : Technology & Engineering
File Size : 90.21 MB
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Underwater Acoustic Modeling and Simulation, Fourth Edition continues to provide the most authoritative overview of currently available propagation, noise, reverberation, and sonar-performance models. This fourth edition of a bestseller discusses the fundamental processes involved in simulating the performance of underwater acoustic systems and emphasizes the importance of applying the proper modeling resources to simulate the behavior of sound in virtual ocean environments. New to the Fourth Edition Extensive new material that addresses recent advances in inverse techniques and marine-mammal protection Problem sets in each chapter Updated and expanded inventories of available models Designed for readers with an understanding of underwater acoustics but who are unfamiliar with the various aspects of modeling, the book includes sufficient mathematical derivations to demonstrate model formulations and provides guidelines for selecting and using the models. Examples of each type of model illustrate model formulations, model assumptions, and algorithm efficiency. Simulation case studies are also included to demonstrate practical applications. Providing a thorough source of information on modeling resources, this book examines the translation of our physical understanding of sound in the sea into mathematical models that simulate acoustic propagation, noise, and reverberation in the ocean. The text shows how these models are used to predict and diagnose the performance of complex sonar systems operating in the undersea environment.
Category: Technology & Engineering