Download or read book Global Model for Sound Absorption in Sea Water Part 3 Arctic Regions written by and published by . This book was released on 1987 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sound absorption in sea water is known to be caused by ionic relaxations involving magnesium sulfate, boric acid and magnesium carbonate. Absorption is regionally dependent, due mainly to the pH-dependence of the boric acid relaxation. In the nominal sea-water pH range 7.7-8.3, the magnitude increases by roughly a factor of four at the lower frequencies. Since pH varies with depth as well as location, absorption also depends on the ray paths. A predictive global model for the World Ocean has developed, employing contour charts of the pH correction-factor (K-factor) at the depths, 0, 0.5, 1, 2, and 4 km. Profiles required for loss-integration along ray paths can be generate by the algorithm provided. This report extends the model to cover Arctic regions. In polar waters, sound speed generally increases monotonically with depth and upward refraction causes a concentration of energy near the surface. Excess attenuation, evidently due to underice scattering, makes long-range propagation feasible only at very low frequencies. Reverberation is also an order of magnitude higher than that at lower latitudes. Thus absorption effects are important only for direct-paths and high frequencies. For depths of 1 km or less, the ranges of concern are therefore on greater than about 50 km in ice- covered waters. The range of pH in the Arctic Ocean is roughly 8.0-8.3, corresponding to an absorption range of a factors of two at most. Because the variability occurs much closer to the surface, the depths 0, 0.1, 0.3, 0.5 and 1 km are found only in basin regions and variability is negligible at these depths.
Download or read book Global Model for Sound Absorption in Sea Water written by R. H. Mellen and published by . This book was released on 1987 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Global Model for Sound Absorption in Sea Water Parts 1 3 written by R. H. Mellen and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Global Model for Sound Absorption in Sea Water written by R. H. Mellen and published by . This book was released on 1987 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Underwater Acoustic Modelling and Simulation Third Edition written by P.C. Etter and published by CRC Press. This book was released on 2003-12-08 with total page 447 pages. Available in PDF, EPUB and Kindle. Book excerpt: Underwater Acoustic Modeling and Simulation examines the translation of our physical understanding of sound in the sea into mathematical models that can simulate acoustic propagation, noise and reverberation in the ocean. These models are used in a variety of research and operational applications to predict and diagnose the performance of complex sonar systems operating in the undersea environment. Previous editions of the book have provided invaluable guidance to sonar technologists, acoustical oceanographers and applied mathematicians in the selection and application of underwater acoustic models. Now that simulation is fast becoming an accurate, efficient and economical alternative to field-testing and at-sea training, this new edition will also provide useful guidance to systems engineers and operations analysts interested in simulating sonar performance. Guidelines for selecting and using available propagation, noise and reverberation models are highlighted. Specific examples of each type of model are discussed to illustrate model formulations, assumptions and algorithm efficiency. Instructive case studies demonstrate applications in sonar simulation.
Download or read book Underwater Acoustic Modelling and Simulation written by P.C. Etter and published by CRC Press. This book was released on 2003-12-08 with total page 447 pages. Available in PDF, EPUB and Kindle. Book excerpt: Underwater Acoustic Modeling and Simulation examines the translation of our physical understanding of sound in the sea into mathematical models that can simulate acoustic propagation, noise and reverberation in the ocean. These models are used in a variety of research and operational applications to predict and diagnose the performance of complex s
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 521 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.
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.
Download or read book Technical Reports Awareness Circular TRAC written by and published by . This book was released on 1987-08 with total page 566 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Global Model for Sound Absorption in Sea Water Impact Study written by and published by . This book was released on 1988 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report examines the impact of the model on sonar performance and the surface and bottom-loss models upon which predictions are currently based. The present analysis is limited mainly to active systems operating in the frequency range 3-4 kHz. The four regions examined are: North Atlantic, North Pacific, Eastern Mediterranean and Norwegian Sea. Comparison of K model predictions with those based on the Thorp formula indicates that two-way path absorption for the first CZ zone ranges from approximately 4 dB less in the North Pacific to 12 dB greater in the Eastern Mediterranean. In the bottom- bounce mode, these values are reduced roughly in proportion to range. The MGS bottom-loss model is based on analysis of one-way paths using the Thorp formula. The difference between the K model and Thorp formula for 10 degree grazing angle in the Eastern Mediterranean is roughly 4 bB, making the actual bottom-loss smaller by about on province number. the differences decrease with increasing grazing angle and are smaller in the other areas. Corrections to the MGS model should therefore be relatively minor.
Download or read book Global Model for Sound Absorption in Sea Water Part 2 GEOSECS PH Data Analysis written by and published by . This book was released on 1987 with total page 67 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ionic relaxations involving magnesium sulfate, boric acid and magnesium, carbonate are known to account for sound absorption in sea water. Regional dependence of sound absorption has been shown to be caused mainly by the pH-dependence of the boric acid relaxation. In the nominal sea water pH range 7.7-8.3, the magnitude can be expected to vary over neatly a factor of four at lower frequencies. Since pH varies with depth as well as locations, net absorption will also depend on the ray paths. An interim global model, based on published pH contours for the World Ocean, has been proposed. Correction factors for the sound-channel, convergence-zone and surface-duct modes are provided by individual contour charts. However, if there is no clearly dominant propagation mode, integrations of loss over all ray paths may be indicated, which requires profiles of correction-factor vs depth. Part-2 reports analysis of pH data obtained during the GEOSECS expeditions 1972-1978. The purpose is to check the accuracy of the global model contous charts and to investigate methods of estimating profiles of correction-factor vs depth. PH profiles for all the stations reported in the Atlantic, Pacific, and Indian Oceans are presented graphically and derived correction factors are listed in tables. Correction- factor contour charts at depths 0, 0.5, 1, 2, an 4 km are also developed and agreement with the earlier versions appears to be within expected experimental error. The five values provided by the contour charts should permit reasonably accurate estimation of the correction-factor profiles in most of the World Ocean.
Download or read book Scientific and Engineering Studies written by R. H. Mellen and published by . This book was released on 1987 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1989-06 with total page 1316 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 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 Government Reports Annual Index written by and published by . This book was released on 1987 with total page 954 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sections 1-2. Keyword Index.--Section 3. Personal author index.--Section 4. Corporate author index.-- Section 5. Contract/grant number index, NTIS order/report number index 1-E.--Section 6. NTIS order/report number index F-Z.
Download or read book The People s Cyclopedia of Universal Knowledge written by and published by . This book was released on 1900 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:
