Download or read book Acoustic Scattering by Axisymmetric Finite Length Bodies An Extension of a 2 Dimensional Conformal Mapping Method written by and published by . This book was released on 2002 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: A general scattering formulation is presented for predicting the far-field scattered pressure from irregular, axisymmetric, finite length bodies for three bound- ary conditions-soft, rigid and fluid. The formulation is an extension of a two dimensional conformal mapping approach D.T. DiPerna and T.K. Stanton, J. Acoust. Soc. Am. 96: 30643079 (1994) to scattering by finite length bodies. This extended formulation, which is inherently numerically efficient to evaluate, involves conformally mapping the surface of an irregular, finite length body to a new, orthogonal coordinate system in which the separation of variables method may be used to solve the Helmholtz equation and satisfy the boundary conditions. Extensive comparisons with previously published results using other formulations are presented. This formulation is shown to be very accurate in the prediction of scattering from smooth, symmetric bodies for a wide range of frequencies (Rayleigh through geometric scattering region), scattering angles (monostatic and bistatic), aspect ratios, and for each of the three boundary conditions listed above. Reasonable agreement has also been demonstrated for irregular, realistic shapes with soft boundary conditions.

Download or read book Acoustic Scattering by Axisymmetric Finite Length Bodies with Application to Fish Measurement and Modeling written by and published by . This book was released on 2002 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis investigates the complexities of acoustic scattering by finite bodies in general and by fish in particular through the development of an advanced acoustic scattering model and detailed laboratory acoustic measurements. A general acoustic scattering model is developed that is accurate and numerically efficient for a wide range of frequencies, angles of orientation, irregular axisymmetric shapes and boundary conditions The model presented is an extension of a two-dimensional conformal mapping approach to scattering by irregular, fine-length bodies of revolution. An extensive series of broadband acoustic backscattering measurements has been conducted involving alewife fish (Alosa pseudoharengus), which are morphologically similar to the Atlantic herring (Glupea harengus). A greater-than-octave bandwidth (40-95 kHz), shaped, linearly swept, frequency modulated signal was used to insonify live, adult alewife that were tethered while being rotated in 1-degree increments over all angles of orientation in two planes of rotation (lateral and dorsal/ventral) Spectral analysis correlates frequency dependencies to morphology and orientation. Pulse compression processing temporally resolves multiple returns from each individual which show good correlation with size and orientation, and demonstrate that there exists more than one significant scattering feature in the animal. Imaging technologies used to exactly measure the morphology of the scattering features of fish include very high-resolution Phase Contrast X-rays (PCX) and Computerized Tomography (CT) scans, which are used for morphological evaluation and incorporation into ;he scattering model. Studies such as this one, which combine scattering models with high-resolution morphological information and high- quality laboratory data, are crucial to the quantitative use of acoustics in the ocean.

Download or read book Acoustic Scattering by Axisymmetric Finite length Bodies with Application to Fish written by D. Benjamin Reeder and published by . This book was released on 2002 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 2004 with total page 1354 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dissertation Abstracts International written by and published by . This book was released on 2003 with total page 860 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Oceans 2005 Europe written by and published by . This book was released on 2005 with total page 734 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Underwater Scattering and Radiation written by Allan D. Pierce and published by Academic Press. This book was released on 2013-10-22 with total page 395 pages. Available in PDF, EPUB and Kindle. Book excerpt: Underwater Scattering and Radiation describes the relevant theoretical foundations of underwater scattering and radiation. Acoustic scattering from elastic solids is discussed, and variational formulations in acoustic radiation and scattering are presented. Surface waves and quasi-cylindrical modes are also explored, along with the Helmholtz-Kirchhoff integral corollaries. Comprised of two chapters, this volume begins with a comprehensive account of scattering by elastic objects, focusing on the classic idealized shapes of spheres and infinite cylinders. The reader is introduced to important concepts such as normal modes, the S-matrix, and the T-matrix as well as resonances, whispering gallery modes, Franz modes, and Stoneley waves. Subsequent sections describe methods for treating scattering by elastic bodies of more general shapes. The T-matrix formalism is discussed and then applied to spheroidal scatterers and finite cylinders. The second chapter analyzes how variational principles can be used in acoustics, with the choice of topics directed toward applications to underwater acoustic radiation and scattering. This book will be of interest to physicists.

Download or read book Electromagnetic And Acoustic Scattering Detection And Inverse Problems Proceedings Of The Conference written by Claude Bourrely and published by World Scientific. This book was released on 1989-03-01 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt: Contents:Light Scattering Problems in Astrophysics (J M Perrin)Surface Integral Operators and their Use in Acoustics and Electromagnetics (A Berthon)Acoustic Diffraction by Slender Bodies of Arbitrary Shape (M Tran-Van-Nhieu)High and Low Energy Approximations for the Electromagnetic Scattering by Irregular Objects (B Torresani)Electromagnetic Scattering and Mutual Interactions Between Closely Spaced Spheroids (J Dalmas & R Deleuil)Acoustical Imaging of 2D Fluid Targets Buried in a Half Space: A Diffraction Tomography Approach Using Line-Sources Insonification (B Duchene et al)Contribution of Radar Polarimetry in Radar Target Discrimination. The “Poincaré Planisphere”: a New Representation Method (E Pottier)Electromagnetic and Acoustic Waves in Random Media: from Propagation to Anderson Localization (B Souillard)Weak Disorder: Homogeneisation Method and Propagation (C Bardos)Coherent Propagation of Surface Acoustic Waves in Quasi-Periodic and Random Arrays of Grooves (D Sornette et al)On Asymptotic Behaviour of Waves States in Random Media (F Bentosela & R Rodriguez)A Study of Acoustic Transmission of Transient Signal in a Inhomogeneous Medium with the Help of a Wavelet Transform. Application to an Air-Water Plane Interface (G Saracco & Ph Tchamitchian)Three-Dimensional Impedance Scattering Theory (P Sabatier)Survey of Optimization Algorithms Applied to Inverse Problems (A Roger)A Linearized Inverse Problem: Acoustic Impedance Tomography of Biological Media (J P Lefebvre)and others Readership: Electrical engineers and mathematicians.

Download or read book Inverse Acoustic and Electromagnetic Scattering Theory written by David Colton and published by Springer Nature. This book was released on 2019-11-06 with total page 518 pages. Available in PDF, EPUB and Kindle. Book excerpt: The inverse scattering problem is central to many areas of science and technology such as radar, sonar, medical imaging, geophysical exploration and nondestructive testing. This book is devoted to the mathematical and numerical analysis of the inverse scattering problem for acoustic and electromagnetic waves. In this fourth edition, a number of significant additions have been made including a new chapter on transmission eigenvalues and a new section on the impedance boundary condition where particular attention has been made to the generalized impedance boundary condition and to nonlocal impedance boundary conditions. Brief discussions on the generalized linear sampling method, the method of recursive linearization, anisotropic media and the use of target signatures in inverse scattering theory have also been added.

Download or read book Coupled mode Modelling of Acoustic Scattering from Three dimensional Axisymmetric Objects written by John A. Fawcett and published by . This book was released on 1997 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Electromagnetic and Acoustic Scattering by Simple Shapes written by J. S. Asvestas and published by . This book was released on 1970 with total page 756 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book represents an exhaustive study of the scattering properties of acoustically soft and hard bodies and of perfect conductors, presented for 15 geometrically-simple shapes. Such shapes are important in their own right and as a basis for synthesizing the radiation and scattering properties of more complex configurations. Each shape is treated in a separate chapter whose contents are presented in stylized format for easy reference. Emphasis is placed on results in the form of formulae and diagrams. Although no detailed derivation are included, an outline of methods in scattering theory is given in the Introduction. (Author).

Download or read book A Finite Element Conjugate Gradient FFT Method for Scattering written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-28 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt: An extension of a two dimensional formulation is presented for a three dimensional body of revolution. With the introduction of a Fourier expansion of the vector electric and magnetic fields, a coupled two dimensional system is generated and solved via the finite element method. An exact boundary condition is employed to terminate the mesh and the fast fourier transformation (FFT) is used to evaluate the boundary integrals for low O(n) memory demand when an iterative solution algorithm is used. By virtue of the finite element method, the algorithm is applicable to structures of arbitrary material composition. Several improvements to the two dimensional algorithm are also described. These include: (1) modifications for terminating the mesh at circular boundaries without distorting the convolutionality of the boundary integrals; (2) the development of nonproprietary mesh generation routines for two dimensional applications; (3) the development of preprocessors for interfacing SDRC IDEAS with the main algorithm; and (4) the development of post-processing algorithms based on the public domain package GRAFIC to generate two and three dimensional gray level and color field maps. Collins, Jeffery D. and Zapp, John and Hsa, Chang-Yu and Volakis, John L. Unspecified Center ...

Download or read book An Investigation of Numerical Techniques for the Fourier Matching Method Acoustic Scattering Model written by and published by . This book was released on 2005 with total page 77 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of extended precision computing and other numerical techniques are evaluated for the Fourier matching method (FMM) acoustic scattering model, initially developed by Assistant Professor D. Benjamin Reeder, CDR/USN (NPS), and Professor Timothy K. Stanton (MIT/WHOI). Theory on acoustic scattering, reverberation, scattering models, conformal mapping, scatterer boundary conditions, floating point arithmetic, computational error, and extended precision computing is presented as a foundation for research development. The paper presents an assessment of the effects of numerical techniques on model output with the initial expectation of obtaining a more accurate, converged solution at higher frequencies, higher modal combinations, and greater eccentricities of scatterer shape. Comparisons to results from Reeder and Stanton (2004) demonstrate effects of executed techniques. Analysis includes an evaluation of the relationship between variable precision settings and computational time, gains in the useful frequency regime of the FMM, and numerical analysis benefits. Demonstrated techniques confirm that increased precision has a positive effect on model performance. The utility of other numerical techniques is discussed, and limitations of current computer systems and other shortfalls are illustrated. A feasibility assessment for Navy use of the FMM and recommendations for further improvements to the FMM are included.

Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1992 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Multiple Scattering written by P. A. Martin and published by Cambridge University Press. This book was released on 2006-08-03 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: Publisher description

Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 974 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book 30 Years of the Landau Institute written by Isaak Markovich Khalatnikov and published by World Scientific. This book was released on 1996 with total page 802 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Landau Institute for Theoretical Physics was created in 1965 by a group of LD Landau's pupils. Very soon, it was widely recognized as one of the world's leading centers in theoretical physics. According to Science Magazine, the Institute in the eighties had the highest citation index among all the scientific organizations in the former Soviet Union. This collection of the best papers of the Institute reflects the development of the many directions in the exact sciences during the last 30 years. The reader can find the original formulations of well-known notions in condensed matter theory, quantum field theory, mathematical physics and astrophysics, which were introduced by members of the Landau Institute.The following are some of the achievements described in this book: monopoles (A Polyakov), instantons (A Belavin et al.), weak crystallization (S Brazovskii), spin superfluidity (I Fomin), finite band potentials (S Novikov) and paraconductivity (A Larkin, L Aslamasov).