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Evaluation Of Improvements To An Underwater Acoustic Propagation Model Based On The Parabolic Equation
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Book Synopsis Evaluation of Improvements to an Underwater Acoustic Propagation Model Based on the Parabolic Equation by : Kirk A. Weatherly
Download or read book Evaluation of Improvements to an Underwater Acoustic Propagation Model Based on the Parabolic Equation written by Kirk A. Weatherly and published by . This book was released on 2000-06 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis examines two implementations of the parabolic equation approximation to the acoustic wave equation aimed at removing three errors inherent to the wide-angle parabolic equation (WAPE) model. First, the selection of the range step size used by the split-step Fourier algorithm affects the convergence of the solution. Second, in certain ocean environments WAPE incorrectly computes the down-range transmission loss. Finally, WAPE does not reproduce the standard normal mode basis set as defined by normal mode theory. A double-precision implementation of the WAPE (DP-WAPE) is developed to evaluate the dependence of solution convergence on the numerical precision of the model. Finally, an implementation that is insensitive to the choice of the reference sound speed (COIPE) is evaluated for its ability to reduce or remove the latter two of these three errors. The stability other WAPE solution was found to be unaffected by the DP-WAPE implementation. The range-step dependence is inherent to the split-step algorithm. The COIPE corrects the transmission loss anomaly and satisfactorily reproduces the standard normal mode basis set.
Book Synopsis Underwater Acoustic Modeling and Simulation by : Paul C. Etter
Download or read book Underwater Acoustic Modeling and Simulation written by Paul C. Etter and published by CRC Press. This book was released on 2017-12-19 with total page 557 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis JAVA-Based Implementation of Monterey-Miami Parabolic Equation (MMPE) Model with Enhanced Visualization and Improved Method of Environmental Definition by : Yonghoon Ha
Download or read book JAVA-Based Implementation of Monterey-Miami Parabolic Equation (MMPE) Model with Enhanced Visualization and Improved Method of Environmental Definition written by Yonghoon Ha and published by . This book was released on 2000-12 with total page 81 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Monterey-Miami Parabolic Equation (MMPE) Model is a full-wave underwater acoustic propagation model that utilizes the split-step Fourier marching algorithm. Previously the MMPE model was implemented in Fortran language and ran with a simple command line interface either in a Unix or DOS command window. After the Fortran code was run, the resulting binary data output file was post-processed using Matlab routines to extract specific field data and present the results in graphical form. This approach requires the user to have installed both Matlab and Fortran compilers. The MMPE model and associated acoustic processing tools are now rewritten in the object-oriented language Java. This new version of the MMPE model built within a Windows framework is called WinMMPE. Integrating the model, the post-processing calculations and the graphics generation together with a graphic user interface has produced a more attractive tool for users. A user-friendly, efficient, and accurate full-wave acoustic propagation model with enhanced visualization can make it easier to assess the spatial transmission loss in the underwater acoustic environment.
Book Synopsis Underwater Acoustic Modeling by : P.C. Etter
Download or read book Underwater Acoustic Modeling written by P.C. Etter and published by CRC Press. This book was released on 1995-11-30 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt: Underwater Acoustic Modeling provides the only comprehensive source on how to translate our physical understanding of sound in the sea into mathematical formulas solvable by computers.
Book Synopsis Review of Numerical Models in Underwater Acoustics, Including Recently Developed Fast-Field Program by : Finn Bruun Jensen
Download or read book Review of Numerical Models in Underwater Acoustics, Including Recently Developed Fast-Field Program written by Finn Bruun Jensen and published by . This book was released on 1984 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two papers given at the NATO Advanced Research Workshop on Hybrid Formulation of Wave Propagation and Scattering on 30 Aug. to 3 Sept. 1983 are published as a review of SACLANTCEN's recent programme in underwater-acoustic modelling. The first briefly reviews the physics of sound propagation in the ocean. In it the mathematical foundations of the most widely used acoustic models (ray, mode, fast field, parabolic equation) are presented and the areas of applicability of the various models are indicated. A few numerical examples are included to show the consistency among the different computer models in overlapping regimes of validity. A series of computational examples is given to demonstrate the applicability of these models to a wide range of general wave-propagation problems. The second paper presents a new numerical model, of the fast field type, where the depth-separated wave equation is solved by a numerical technique very similar to that used in finite-element programs. The speed improvement over existing models of the same type is considerable, especially in cases with many sources and receivers. The model has been used for studying both seismic pulse propagation in shallow water and reflection of pulsed ultrasonic beams from a fluid/solid interface.
Book Synopsis An Evaluation of Methods for Characterizing the Air/Water Interface for Parabolic Equation Transmission Loss Modeling by :
Download or read book An Evaluation of Methods for Characterizing the Air/Water Interface for Parabolic Equation Transmission Loss Modeling written by and published by . This book was released on 2010 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proper characterization of underwater acoustic transmission loss (TL) relies on proper treatment of the air/water and water/sediment interfaces. This paper will focus on how the air/water interface is treated in parabolic equation (PE) models such as the range dependent acoustic model (RAM) [Collins, M.D., "Applications and time-domain solution of higher-order parabolic equations in underwater acoustics," J. Acoust. Soc. Am., 86 (3), 1097-1102, 1989] and the finite element parabolic equation (FEPE) model [Collins, M.D., "A higher-order parabolic equation for wave propagation in an ocean overlying an elastic bottom", J. Acoust. Soc. Am. 86, 1459-1464, 1989]. Two surface loss methods have been implemented in RAM, a surface loss versus angle (LVA) and a conformal mapping (CM) method. Additionally, the CM method has been implemented in FEPE. These two methods are discussed and compared for realistic test cases and a third option, which has accuracy consistent with the CM but speed more aligned with the LVA approach is discussed.
Book Synopsis Ocean Acoustic Propagation by Finite Difference Methods by : D. Lee
Download or read book Ocean Acoustic Propagation by Finite Difference Methods written by D. Lee and published by Elsevier. This book was released on 2014-06-28 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: A concise guide to the theory and application of numerical methods for predicting ocean acoustic propagation, also providing an introduction to numerical methods, with an overview of those methods presently in use. An in-depth development of the implicit-finite-difference technique is presented together with bench-mark test examples included to demonstrate its application to realistic ocean environments. Other applications include atmospheric acoustics, plasma physics, quantum mechanics, optics and seismology.
Book Synopsis Maps of the Military Campaigns of the Cumberland, Tennessee & Mississippi Rivers by :
Download or read book Maps of the Military Campaigns of the Cumberland, Tennessee & Mississippi Rivers written by and published by . This book was released on 1862 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Wave Propagation and Underwater Acoustics by : Joseph Bishop Keller
Download or read book Wave Propagation and Underwater Acoustics written by Joseph Bishop Keller and published by Springer. This book was released on 1977 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 with total page 224 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 Underwater Acoustic Modeling and Simulation, Fifth Edition by : Paul C. Etter
Download or read book Underwater Acoustic Modeling and Simulation, Fifth Edition written by Paul C. Etter and published by CRC Press. This book was released on 2018-03-15 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt: This newest edition adds new material to all chapters, especially in mathematical propagation models and special applications and inverse techniques. It has updated environmental-acoustic data in companion tables and core summary tables with the latest underwater acoustic propagation, noise, reverberation, and sonar performance models. Additionally, the text discusses new applications including underwater acoustic networks and channel models, marine-hydrokinetic energy devices, and simulation of anthropogenic sound sources. It further includes instructive case studies to demonstrate applications in sonar simulation.
Book Synopsis Principles of Sonar Performance Modelling by : Michael Ainslie
Download or read book Principles of Sonar Performance Modelling written by Michael Ainslie and published by Springer Science & Business Media. This book was released on 2010-09-14 with total page 727 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sonar performance modelling (SPM) is concerned with the prediction of quantitative measures of sonar performance, such as probability of detection. It is a multi-disciplinary subject, requiring knowledge and expertise in the disparate fields of underwater acoustics, acoustical oceanography, sonar signal processing and statistical detection theory. No books have been published on this subject, however, since the 3rd edition of Urick’s classic work 25 years ago and so Dr Ainslie’s book will fill a much-needed gap in the market. Currently, up-to-date information can only be found, in different forms and often with conflicting information, in various journals, conference and textbook publications. Dr Michael Ainslie is eminently qualified to write this unique book. He has worked on sonar performance modeling problems since 1983. He has written many peer reviewed research articles and conference papers related to sonar performance modeling, making contributions in the fields of sound propagation and detection theory.
Book Synopsis Solving the Parabolic Equation for Underwater Acoustic Propagation by the Split-step Algorithm by :
Download or read book Solving the Parabolic Equation for Underwater Acoustic Propagation by the Split-step Algorithm written by and published by . This book was released on 1982 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Predicting the Effects of Sea Surface Scatter on Broadband Pulse Propagation with an Ocean Acoustic Parabolic Equation Model by : Richard M. Ead
Download or read book Predicting the Effects of Sea Surface Scatter on Broadband Pulse Propagation with an Ocean Acoustic Parabolic Equation Model written by Richard M. Ead and published by . This book was released on 2004-06-01 with total page 93 pages. Available in PDF, EPUB and Kindle. Book excerpt: Littoral waters when compared to the open ocean create an environment of greater reverberation with acoustic energy scattering from the sea surface, bottom, topographic features, and regions that lack homogeneity within the volume. If the ocean surface is rough on the scale of an acoustic wavelength, considerable scattering can occur that can significantly influence coherent propagation. Because the rough surface is also evolving dynamically such scattering can introduce Doppler shifting and spreading of the acoustic pulse spectrum. This thesis builds upon prior efforts in ocean acoustic modeling and is focused on examining surface scattering and its affect upon coherent propagation. The dynamics/physics associated with sea surface scattering are explored in detail and mathematical relationships are developed and employed in revisions to the Monterey Miami Parabolic Equation (MMPE) model. The thesis provides background information associated with the MMPE and highlights earlier work related to surface scattering. It presents a formal analysis of an exact surface scattering approach in the context of a continuous wave (CW) benchmark exercise and the Doppler shifts associated with a dynamic rough surface. It expands on prior rough sea surface work to include modeling based on an empirical fetch-limited ocean wave spectrum and compares modeling results with measured data. Interest in broadband pulse propagation in shallow water is increasing with the need for improved active sonar systems and with the growth of applications such as underwater acoustic communications.
Book Synopsis Incorporating Realistic Acoustic Propagation Models in Simulation of Underwater Acoustic Networks: A Statistical Approach by :
Download or read book Incorporating Realistic Acoustic Propagation Models in Simulation of Underwater Acoustic Networks: A Statistical Approach written by and published by . This book was released on 2006 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: The development of protocols to advance the state of the art in Underwater Acoustic Networks (UANs) relies on the use of computer simulations to analyze protocol performance. It is typical for designers to abstract away much of the detail of the physical environment in order to simplify the development of the simulation and ensure the simulation runtime performance is reasonable. The validity of the simulation results becomes questionable. There are, though, very high fidelity models developed by acoustic engineers and physicists for predicting acoustic propagation characteristics. In addition to these models, empirical data collections have been generated for many geographic regions of interest to UAN planners. However, incorporating these engineering and physics models or data collections into a network simulation is problematic, as the models are computationally complex and the data sets are not directly usable for acoustic signal propagation characterization. This paper presents a statistical method for developing a computationally efficient and simulation friendly approximation of a physics model of path loss. This method may also be used to adapt empirical data sets for use in network simulation in the same manner. The method was applied to the output of the Monterey-Miami Parabolic Equation model to assess its impact on the runtime performance of an OPNET-based simulation. Results of that simulation are compared to results from a previous OPNET simulation that simply used distance to determine reception. The simulation results confirm the incorporation of the MMPE approximation does not noticeably impact the runtime performance of the simulation. Anecdotally, the simulation confirms earlier results the suggest contention based access controls without collision avoidance techniques may outperform the typical access technique adapted from wireless radio networks that employs collision avoidance even in the high load regime, contrary to conventional wisdom.
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 Oceanic Acoustic Modelling. Proceedings of a Conference Held at SACLANTCEN on 8-11 September 1975. Part 8. Sonar Models by : Wolfgang Bachmann
Download or read book Oceanic Acoustic Modelling. Proceedings of a Conference Held at SACLANTCEN on 8-11 September 1975. Part 8. Sonar Models written by Wolfgang Bachmann and published by . This book was released on 1975 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: ;Contents: A technique of comparative analysis of underwater sound transmission loss curves; Connection between the solutions of the Helmholtz and parabolic equations for sound propagation; Computer models for underwater sound propagation; Assessment techniques for computer models of sound propagation.
