Download or read book The Numerical Solution of the Helmholtz Equation for Wave Propagation Problems in Underwater Acoustics written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-08-06 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Helmholtz Equation (-delta-K(2)n(2))u=0 with a variable index of refraction, n, and a suitable radiation condition at infinity serves as a model for a wide variety of wave propagation problems. A numerical algorithm was developed and a computer code implemented that can effectively solve this equation in the intermediate frequency range. The equation is discretized using the finite element method, thus allowing for the modeling of complicated geometrices (including interfaces) and complicated boundary conditions. A global radiation boundary condition is imposed at the far field boundary that is exact for an arbitrary number of propagating modes. The resulting large, non-selfadjoint system of linear equations with indefinite symmetric part is solved using the preconditioned conjugate gradient method applied to the normal equations. A new preconditioner is developed based on the multigrid method. This preconditioner is vectorizable and is extremely effective over a wide range of frequencies provided the number of grid levels is reduced for large frequencies. A heuristic argument is given that indicates the superior convergence properties of this preconditioner. Bayliss, A. and Goldstein, C. I. and Turkel, E. Unspecified Center NASA-CR-172454, NAS 1.26:172454, ICASE-84-49 NAS1-17130; DE-AC02-76CH-00016; RTOP 505-31-83
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.
Download or read book Effective Computational Methods for Wave Propagation written by Nikolaos A. Kampanis and published by CRC Press. This book was released on 2008-02-25 with total page 707 pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to the increase in computational power and new discoveries in propagation phenomena for linear and nonlinear waves, the area of computational wave propagation has become more significant in recent years. Exploring the latest developments in the field, Effective Computational Methods for Wave Propagation presents several modern, valuable
Download or read book Applied Underwater Acoustics written by Thomas Neighbors and published by Elsevier. This book was released on 2017-01-19 with total page 982 pages. Available in PDF, EPUB and Kindle. Book excerpt: Applied Underwater Acoustics meets the needs of scientists and engineers working in underwater acoustics and graduate students solving problems in, and preparing theses on, topics in underwater acoustics. The book is structured to provide the basis for rapidly assimilating the essential underwater acoustic knowledge base for practical application to daily research and analysis. Each chapter of the book is self-supporting and focuses on a single topic and its relation to underwater acoustics. The chapters start with a brief description of the topic's physical background, necessary definitions, and a short description of the applications, along with a roadmap to the chapter. The subtopics covered within individual subchapters include most frequently used equations that describe the topic. Equations are not derived, rather, assumptions behind equations and limitations on the applications of each equation are emphasized. Figures, tables, and illustrations related to the sub-topic are presented in an easy-to-use manner, and examples on the use of the equations, including appropriate figures and tables are also included. - Provides a complete and up-to-date treatment of all major subjects of underwater acoustics - Presents chapters written by recognized experts in their individual field - Covers the fundamental knowledge scientists and engineers need to solve problems in underwater acoustics - Illuminates, in shorter sub-chapters, the modern applications of underwater acoustics that are described in worked examples - Demands no prior knowledge of underwater acoustics, and the physical principles and mathematics are designed to be readily understood by scientists, engineers, and graduate students of underwater acoustics - Includes a comprehensive list of literature references for each chapter
Download or read book Acoustic Interactions with Submerged Elastic Structures written by Ardshir Guran and published by World Scientific. This book was released on 2002 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt: This series of volumes constitutes an outstanding collection of contributions by the most active research workers in the area of acoustics and mechanics. It brings the reader up to date on the status of the various aspects of research in this field. The volumes should preserve their value for a long time, as they represent a monument to the achievements of human research capabilities in the underwater-acoustics aspects of the environment.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book Theoretical And Computational Acoustics 97 written by Er-chang Shang and published by World Scientific. This book was released on 1999-05-11 with total page 762 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume is dedicated to Dr Ding Lee for his untiring efforts in promoting the advancement of theoretical and computational acoustics.This proceedings volume provides a forum for active researchers to discuss the state-of-the-art developments and results in theoretical and computational acoustics, covering aero-, seismo- and ocean acoustics and related topics. It discusses multidimensional wave propagation modeling, methods of computational acoustics, wave propagation in rocks, fluid-solid interfaces, nonlinear acoustics, neural networks, real applications and experimental results.
Download or read book Shear Waves in Marine Sediments written by J.M Hovem and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 593 pages. Available in PDF, EPUB and Kindle. Book excerpt: Shear waves and closely related interface waves (Rayleigh, Stoneley and Scholte) play an important role in many areas of engineering, geophysics and underwater acoustics. In some cases interest is focused on large-amplitude waves of low frequency such as those associ ated with earthquakes and nuclear explosions; in other cases low amplitude waves, which have often travelled great distances through the sediment, are of interest. Both low and high frequency shear and interface waves are often used for seafloor probing and sediment characterization. As a result of the wide spectrum of different interests, different disciplines have developed lines of research and a literature particularly suited to their own problems. For example water-column acousticians view the seafloor sediment as the lower boundary of their domain and are interested in shear and interface waves in the near bottom sediments mainly from the standpoint of how they influence absorption and reflection at this boundary. On the other hand, geophysicists seeking deep oil deposits are interested in the maximum penetration into the sediments and the tell-tale characteristics of the seismic waves that have encountered potential oil or gas bearing strata. In another area, geotechnical engineers use shear and interface waves to study soil properties necessary for the design and the siting of seafloor structures.
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1977 with total page 1166 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Theoretical And Computational Acoustics 2001 written by T F Gao and published by World Scientific. This book was released on 2002-07-25 with total page 691 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains 67 papers presented at ICTCA2001. It includes three keynote addresses surveying the frontier developments in computational and theoretical acoustics. The papers cover aero-, seismo- and ocean acoustics, as well as ultrasonics. Computational methods, numerical simulation, theoretical analysis and experimental results are emphasized by different papers.The proceedings have been selected for coverage in:Index to Scientific & Technical Proceedings (ISTP CDROM version / ISI Proceedings)
Download or read book Computational Science and Its Applications ICCSA 2020 written by Osvaldo Gervasi and published by Springer Nature. This book was released on 2020-09-30 with total page 1091 pages. Available in PDF, EPUB and Kindle. Book excerpt: The seven volumes LNCS 12249-12255 constitute the refereed proceedings of the 20th International Conference on Computational Science and Its Applications, ICCSA 2020, held in Cagliari, Italy, in July 2020. Due to COVID-19 pandemic the conference was organized in an online event. Computational Science is the main pillar of most of the present research, industrial and commercial applications, and plays a unique role in exploiting ICT innovative technologies. The 466 full papers and 32 short papers presented were carefully reviewed and selected from 1450 submissions. Apart from the general track, ICCSA 2020 also include 52 workshops, in various areas of computational sciences, ranging from computational science technologies, to specific areas of computational sciences, such as software engineering, security, machine learning and artificial intelligence, blockchain technologies, and of applications in many fields.
Download or read book Recent Advances in Aeroacoustics written by A. Krothapalli and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 511 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Joint Institute for Aeronautics and Acoustics at Stanford University was established in October 1973 to provide an academic environment for long-term cooperative research between Stanford and NASA Ames Research Center. Since its establishment, the Institute has conducted theoretical and experimental work in the areas of aerodynamics, acoustics, fluid mechanics, flight dynamics, guidance and control, and human factors. This research has involved Stanford faculty, research associates, graduate students, and many distinguished visitors in collaborative efforts with the research staff of NASA Ames Research Center. The occasion of the Institute's tenth anniversary was used to reflect back on where that research has brought us, and to consider where our endeavors should be directed next. Thus, an International Symposium was held to review recent advances in the fields relevant to the activities of the Institute and to discuss the areas of research to be undertaken in the future. This anniversary was also chosen as an opportunity to honor one of the Institute's founders and its director, Professor Krishnamurty Karamcheti. It has been his crea tive inspiration that has provided the ideal research environment at the Joint Institute.
Download or read book Monthly Catalog of United States Government Publications written by United States. Superintendent of Documents and published by . This book was released on 1985 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: February issue includes Appendix entitled Directory of United States Government periodicals and subscription publications; September issue includes List of depository libraries; June and December issues include semiannual index
Download or read book Monthly Catalogue United States Public Documents written by and published by . This book was released on 1985 with total page 1258 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Theoretical and Computational Acoustics 2001 written by Er-Chang Shang and published by World Scientific. This book was released on 2002 with total page 691 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains 67 papers presented at ICTCA2001. It includes three keynote addresses surveying the frontier developments in computational and theoretical acoustics. The papers cover aero-, seismo- and ocean acoustics, as well as ultrasonics. Computational methods, numerical simulation, theoretical analysis and experimental results are emphasized by different papers.
Download or read book Scientific and Technical Information Output of the Langley Research Center for Calendar Year 1984 written by and published by . This book was released on 1985 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fifth International Conference on Mathematical and Numerical Aspects of Wave Propagation written by Alfredo Berm?dez and published by SIAM. This book was released on 2000-01-01 with total page 1062 pages. Available in PDF, EPUB and Kindle. Book excerpt: This conference was held in Santiago de Compostela, Spain, July 10-14, 2000. This volume contains papers presented at the conference covering a broad range of topics in theoretical and applied wave propagation in the general areas of acoustics, electromagnetism, and elasticity. Both direct and inverse problems are well represented. This volume, along with the three previous ones, presents a state-of-the-art primer for research in wave propagation. The conference is conducted by the Institut National de Recherche en Informatique et en Automatique with the cooperation of SIAM.
