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Three Dimensional Acoustic Propagation Through Shallow Water Internal Surface Gravity And Bottom Sediment Waves
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Book Synopsis Three-dimensional Acoustic Propagation Through Shallow Water Internal, Surface Gravity and Bottom Sediment Waves by : Alexey Alexandrovich Shmelev
Download or read book Three-dimensional Acoustic Propagation Through Shallow Water Internal, Surface Gravity and Bottom Sediment Waves written by Alexey Alexandrovich Shmelev and published by . This book was released on 2011 with total page 193 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes the physics of fully three-dimensional low frequency acoustic interaction with internal waves, bottom sediment waves and surface swell waves that are often observed in shallow waters and on continental slopes. A simple idealized model of the ocean waveguide is used to analytically study the properties of acoustic normal modes and their perturbations due to waves of each type. The combined approach of a semi-quantitative study based on the geometrical acoustics approximation and on fully three-dimensional coupled mode numerical modeling is used to examine the azimuthal dependence of sound wave horizontal reflection from, transmission through and ducting between straight parallel waves of each type. The impact of the natural crossings of nonlinear internal waves on horizontally ducted sound energy is studied theoretically and modeled numerically using a three-dimensional parabolic equation acoustic propagation code. A realistic sea surface elevation is synthesized from the directional spectrum of long swells and used for three-dimensional numerical modeling of acoustic propagation. As a result, considerable normal mode amplitude scintillations were observed and shown to be strongly dependent on horizontal azimuth, range and mode number. Full field numerical modeling of low frequency sound propagation through large sand waves located on a sloped bottom was performed using the high resolution bathymetry of the mouth of San Francisco Bay. Very strong acoustic ducting is shown to steer acoustic energy beams along the sand wave's curved crests.
Book Synopsis A Three-dimensional Coupled Normal Mode Model for Sound Propagation in Shallow Water with Irregular Bottom Bathymetry by : George A. Sagos
Download or read book A Three-dimensional Coupled Normal Mode Model for Sound Propagation in Shallow Water with Irregular Bottom Bathymetry written by George A. Sagos and published by . This book was released on 1992 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :Boris G. Katsnelson Publisher :Springer Science & Business Media ISBN 13 :9783540426448 Total Pages :296 pages Book Rating :4.4/5 (264 download)
Book Synopsis Shallow Water Acoustics by : Boris G. Katsnelson
Download or read book Shallow Water Acoustics written by Boris G. Katsnelson and published by Springer Science & Business Media. This book was released on 2002-05-01 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this book is to present the main theoretical approaches and models in shallow water acoustics as well as different experimental results. The focus is primarily concentrated on physical results describing the sound field in wave length. The authors show dynamic phenomena (tides, internal waves) from the perspective of acoustic influence as well as the scattering of sound over the macroscopic body in shallow water waveguide. The method of acoustic probing can be used by physicists, geophysicists, geologists and oceanographers.
Book Synopsis Numerical Ocean Acoustic Propagation In Three Dimensions by : Ding Lee
Download or read book Numerical Ocean Acoustic Propagation In Three Dimensions written by Ding Lee and published by World Scientific. This book was released on 1995-12-31 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces a comprehensive mathematical formulation of the three-dimensional ocean acoustic propagation problem by means of functional and operator splitting techniques in conjunction with rational function approximations. It presents various numerical solutions of the model equation such as finite difference, alternating direction and preconditioning. The detailed analysis of the concept of 3D, N x 2D and 2D problems is very useful not only mathematically and physically, but also computationally. The inclusion of a complete detailed listing of proven computer codes which have been in use by a number of universities and research organizations worldwide makes this book a valuable reference source. Advanced knowledge of numerical methods, applied mathematics and ocean acoustics is not required to understand this book. It is oriented toward graduate students and research scientists to use for research and application purposes.
Book Synopsis Acoustic Focusing in Shallow Water and Bubble Radiation Effects by :
Download or read book Acoustic Focusing in Shallow Water and Bubble Radiation Effects written by and published by . This book was released on 2005 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: The long-term goals of the "Acoustic Focusing in Shallow Water and Bubble Radiation Effects" project is as follows: (1) understand the role of wave-induced bubbles in the upper ocean boundary layer on the performance of underwater communications systems and ambient noise generation, (2) study the implications of focusing by surface gravity waves on Doppler sonar and acoustic communications systems in shallow and very shallow water, and (3) study the performance of acoustic vector sensors in very shallow water. Goal 1 of this research is to measure the radiation strength of fragmenting bubbles as a function of bubble size. This research is based on the importance of ambient noise in the ocean for the operation of acoustic systems in general, and the importance of upper ocean boundary layer bubbles on the performance of underwater acoustic systems. The connection between the noise radiated by white caps and wind speed is well known, but the connection between bubble creation mechanics within white caps and noise level is not well understood. Recent advances in our understanding of the scale dependence of bubble creation mechanisms in breaking waves has raised the possibility of creating a quantitative link between ambient noise level and bubble production rates by ocean waves. Goal 2 is to measure and model the three-dimensional effects of sound focusing by shoaling surf. Wave crests focus surface reflections into high-intensity regions that propagate through the water column. These high intensity regions have a first-order impact on the performance of underwater communications systems in the surf zone. Goal 3 determines how closely the performance of an array of vector sensors deployed in an ocean environment approaches theoretical prediction; compares the performance of vector sensors with pressure sensors; and determines if any differences in performance can be related to the relevant physical properties of the water column, such as internal wave activity.
Book Synopsis Experimental Acoustic Inversion Methods for Exploration of the Shallow Water Environment by : Andrea Caiti
Download or read book Experimental Acoustic Inversion Methods for Exploration of the Shallow Water Environment written by Andrea Caiti and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years, research on acoustic remote sensing of the ocean has evolved considerably, especially in studying complex physical and biological processes in shallow water environments. To review the state of the art, an international workshop was held at Carvoeiro, Portugal, in March 1999, bringing together leading international researchers in the field. In contrast to much of the recent theoretical work, emphasis was placed on the experimental validation of the techniques. This volume, based on presentations at this workshop, summarizes a range of diverse and innovative applications. The invited contributions explore the use of acoustics to measure bottom properties and morphology, as well as to probe buried objects within the sediment. Within the water column, sound is applied to imaging of oceanographic features such as currents and tides or monitoring of marine life. Another key theme is the use of sound to solve geometric inverse problems for precise tracking of undersea vehicles. Audience: This volume should be useful both to the novice seeking an introduction to the field and to advanced researchers interested in the latest developments in acoustic sensing of the ocean environment. The workshop was sponsored by the Fundação para a Ciêcia e a Tecnologia (Portuguese Foundation for Science and Technology).
Book Synopsis Measurement and Modeling of Low Frequency Acoustic Wave Propagation and Scattering in Shallow Water with Comprehensive Subbottom Structure Measurements by :
Download or read book Measurement and Modeling of Low Frequency Acoustic Wave Propagation and Scattering in Shallow Water with Comprehensive Subbottom Structure Measurements written by and published by . This book was released on 1996 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: A high resolution acoustic crosswell tomography technique was developed for accurate measurements of variabilities of density, velocity, shear strength and permeability within the sediments. An analytical expression for the three dimensional wave number spectra of these sediment properties has been obtained. Acoustics scattering from sediment volume has been obtained as a function of the three dimensional spectra of velocity and density variabilities. Work continues to quantify the relation between the variabilities of sediment properties and acoustic bottom scattering. A method to measure the ocean wave directional spectra using a single buried ocean bottom seismometer and a pressure senser has been developed and sea tested successfully.
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applied mechanics reviews written by and published by . This book was released on 1948 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Sound Propagation in the Sea by : Robert J. Urick
Download or read book Sound Propagation in the Sea written by Robert J. Urick and published by . This book was released on 1979 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technical Report CERC written by and published by . This book was released on 1983 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Acoustic Sensing Techniques for the Shallow Water Environment by : Andrea Caiti
Download or read book Acoustic Sensing Techniques for the Shallow Water Environment written by Andrea Caiti and published by Springer Science & Business Media. This book was released on 2006-09-21 with total page 331 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the collection of papers from the second workshop on Experimental Acoustic Inversion Techniques for Exploration of the Shallow Water Environment. Acoustic techniques provide the most effective means for remote sensing of ocean and sea floor processes, and for probing the structure beneath the sea floor. No other energy propagates as efficiently in the ocean: radio waves and visible light are severely limited in range because the ocean is a highly conductive medium. However, sound from breaking waves and coastal shipping can be heard throughout the ocean, and marine mammals communicate acoustically over basin scale distances. The papers in this book indicate a high level of research interest that has generated significant progress in development and application of experimental acoustic inversion techniques. The applications span a broad scope in geosciences, from geophysical, biological and even geochemical research. The list includes: estimation of geotechnical properties of sea bed materials; navigation and mapping of the sea floor; fisheries, aquaculture and sea bed habitat assessment; monitoring of marine mammals; sediment transport; and investigation of natural geohazards in marine sediments. Audience This book is primarily intended for physicists and engineers working in underwater acoustics and oceanic engineering. It will also be of interest to marine biologists, geophysicists and oceanographers as potential users of the methodologies and techniques described in the book contributions.
Book Synopsis Spatial Coherence in a Shallow Water Waveguide by : Jie Yang
Download or read book Spatial Coherence in a Shallow Water Waveguide written by Jie Yang and published by . This book was released on 2007 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: In shallow water environments, sound propagation experiences multiple interactions with the surface/bottom interfaces, with hydrodynamic disturbances such as internal waves, and with tides and fronts. It is thus very difficult to make satisfactory predictions of sound propagation in shallow water. Given that many of the ocean characteristics can be modeled as stochastic processes, the statistical measure, spatial coherence, is consequently an important quantity. Spatial coherence provides valuable information for array performance predictions. However, for the case of long-range, low frequency propagation, studies of spatial coherence influenced by various environmental parameters are limited insofar as having the appropriate environmental data with which to model and interpret the results.
Book Synopsis Shallow-water Acoustics by : Renhe Zhang
Download or read book Shallow-water Acoustics written by Renhe Zhang and published by . This book was released on 1997 with total page 660 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Modeling Three-dimensional Acoustic Propagation in Underwater Waveguides Using the Longitudinally Invariant Finite Element Method by : Benjamin Michael Goldsberry
Download or read book Modeling Three-dimensional Acoustic Propagation in Underwater Waveguides Using the Longitudinally Invariant Finite Element Method written by Benjamin Michael Goldsberry and published by . This book was released on 2014 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three-dimensional acoustic propagation in shallow water waveguides is studied using the longitudinally invariant finite element method. This technique is appropriate for environments with lateral variations that occur in only one dimension. In this method, a transform is applied to the three-dimensional Helmholtz equation to remove the range-independent dimension. The finite element method is employed to solve the transformed Helmholtz equation for each out-of-plane wavenumber. Finally, the inverse transform is used to transform the pressure field back to three-dimensional spatial coordinates. Due to the oscillatory nature of the inverse transform, two integration techniques are developed. The first is a Riemann sum combined with a wavenumber sampling method that efficiently captures the essential components of the integrand. The other is a modified adaptive Clenshaw-Curtis quadrature. Three-dimensional transmission loss is computed for a Pekeris waveguide, underwater wedge, and Gaussian canyon. For each waveguide, the two integration schemes are compared in terms of accuracy and efficiency.
Book Synopsis The Journal of the Acoustical Society of America by : Acoustical Society of America
Download or read book The Journal of the Acoustical Society of America written by Acoustical Society of America and published by . This book was released on 2007 with total page 1552 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis High-Resolution, Three-Dimensional Measurements of Low-Frequency Sound Propagation in Shallow Water by : George Frisk
Download or read book High-Resolution, Three-Dimensional Measurements of Low-Frequency Sound Propagation in Shallow Water written by George Frisk and published by . This book was released on 1998 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: An overview is presented of the Model Mapping Experiment (MOMAX), in which both fixed and moving source configurations were used to transmit several pure tones in the frequency range 50 - 300 Hz in shallow water. The magnitudes and phases of these signals were recorded on several freely drifting buoys, each containing a hydrophone, GPS and acoustic navigation, and radio telemetry. High-resolution, three-dimensional measurements of the sound field were made out to ranges of 10 km and illustrate the influence of the laterally varying seabed in both the space and wavenumber domains. In addition, the phases of the measured signals show a remarkably high level of stability and regularity which can be exploited to make accurate estimates of the relative source/receiver speed from measurements of the time rate-of-change of the phase.
