Numerical Methods to Implement Time Reversal of Waves Propagating in Complex Random Media

Numerical Methods to Implement Time Reversal of Waves Propagating in Complex Random Media PDF Author: Kurang Jvalant Mehta
Publisher:
ISBN:
Category :
Languages : en
Pages : 55

Get Book Here

Book Description
Keywords: Finite Difference Time Domain Method, Boundary Integral Method, Transfer Matrix Method, Wave Propagation, Time Reversal.

Numerical Methods to Implement Time Reversal of Waves Propagating in Complex Random Media

Numerical Methods to Implement Time Reversal of Waves Propagating in Complex Random Media PDF Author: Kurang Jvalant Mehta
Publisher:
ISBN:
Category :
Languages : en
Pages : 55

Get Book Here

Book Description
Keywords: Finite Difference Time Domain Method, Boundary Integral Method, Transfer Matrix Method, Wave Propagation, Time Reversal.

Numerical Methods to Implement Time Reversal of Waves Propagating in Complex Random Media

Numerical Methods to Implement Time Reversal of Waves Propagating in Complex Random Media PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

Get Book Here

Book Description
A time reversal mirror is a device capable of receiving a signal in time, keeping it in memory, and sending it back into the same medium in the reversed direction of time. The main effect is the fascinating refocusing of the scattered signal, which is formed by sending the pulse into a complex medium, after time reversal through the same medium. The refocused signal is a pulse with shape similar to the initial pulse along with some low amplitude noise. This surprising effect has a great potential for application in domains such as medical imaging, underwater acoustics and wireless communication. Time reversal is studied in reflection and transmission. In both cases, we demonstrate the self-averaging properties of the time reversed refocused pulse. An accurate numerical method for simulating waves propagating in complex one-dimensional media is employed. Numerical simulations are used to reproduce the time-reversal self-averaging effect which takes place in randomly layered media. The effect of refocusing is enhanced in a regime where the inhomogenities are smaller than the pulse, which propagates over long distances compared to its width. Time Reversal can be implemented using several numerical methods including Transfer Matrix, Finite Difference Time Domain (FDTD) & Boundary Integral Methods. This thesis includes a comprehensive comparison of the methods in terms of speed and accuracy. The most efficient method for implementing time reversal is then used to obtain numerical evidence for potential use of a sliding window time-reversal technique for detecting a buried cavity/object inside the medium. The numerical methods are well adapted for generalization to the multi-dimensional case.

Wave Propagation in Complex Media

Wave Propagation in Complex Media PDF Author: George Papanicolaou
Publisher: Springer Science & Business Media
ISBN: 1461216788
Category : Mathematics
Languages : en
Pages : 301

Get Book Here

Book Description
This IMA Volume in Mathematics and its Applications WAVE PROPAGATION IN COMPLEX MEDIA is based on the proceedings of two workshops: • Wavelets, multigrid and other fast algorithms (multipole, FFT) and their use in wave propagation and • Waves in random and other complex media. Both workshops were integral parts of the 1994-1995 IMA program on "Waves and Scattering." We would like to thank Gregory Beylkin, Robert Burridge, Ingrid Daubechies, Leonid Pastur, and George Papanicolaou for their excellent work as organizers of these meetings. We also take this opportunity to thank the National Science Foun dation (NSF), the Army Research Office (ARO, and the Office of Naval Research (ONR), whose financial support made these workshops possible. A vner Friedman Robert Gulliver v PREFACE During the last few years the numerical techniques for the solution of elliptic problems, in potential theory for example, have been drastically improved. Several so-called fast methods have been developed which re duce the required computing time many orders of magnitude over that of classical algorithms. The new methods include multigrid, fast Fourier transforms, multi pole methods and wavelet techniques. Wavelets have re cently been developed into a very useful tool in signal processing, the solu tion of integral equation, etc. Wavelet techniques should be quite useful in many wave propagation problems, especially in inhomogeneous and nonlin ear media where special features of the solution such as singularities might be tracked efficiently.

Wave Propagation and Time Reversal in Randomly Layered Media

Wave Propagation and Time Reversal in Randomly Layered Media PDF Author: Jean-Pierre Fouque
Publisher: Springer Science & Business Media
ISBN: 0387498087
Category : Science
Languages : en
Pages : 623

Get Book Here

Book Description
The content of this book is multidisciplinary by nature. It uses mathematical tools from the theories of probability and stochastic processes, partial differential equations, and asymptotic analysis, combined with the physics of wave propagation and modeling of time reversal experiments. It is addressed to a wide audience of graduate students and researchers interested in the intriguing phenomena related to waves propagating in random media. At the end of each chapter there is a section of notes where the authors give references and additional comments on the various results presented in the chapter.

Wave Propagation and Time Reversal in Randomly Layered Media

Wave Propagation and Time Reversal in Randomly Layered Media PDF Author: Jean-Pierre Fouque
Publisher: Springer
ISBN: 9780387511481
Category : Science
Languages : en
Pages : 0

Get Book Here

Book Description
The content of this book is multidisciplinary by nature. It uses mathematical tools from the theories of probability and stochastic processes, partial differential equations, and asymptotic analysis, combined with the physics of wave propagation and modeling of time reversal experiments. It is addressed to a wide audience of graduate students and researchers interested in the intriguing phenomena related to waves propagating in random media. At the end of each chapter there is a section of notes where the authors give references and additional comments on the various results presented in the chapter.

The Topology of 4-Manifolds

The Topology of 4-Manifolds PDF Author: Robion C. Kirby
Publisher: Springer
ISBN: 354046171X
Category : Mathematics
Languages : en
Pages : 114

Get Book Here

Book Description
This book presents the classical theorems about simply connected smooth 4-manifolds: intersection forms and homotopy type, oriented and spin bordism, the index theorem, Wall's diffeomorphisms and h-cobordism, and Rohlin's theorem. Most of the proofs are new or are returbishings of post proofs; all are geometric and make us of handlebody theory. There is a new proof of Rohlin's theorem using spin structures. There is an introduction to Casson handles and Freedman's work including a chapter of unpublished proofs on exotic R4's. The reader needs an understanding of smooth manifolds and characteristic classes in low dimensions. The book should be useful to beginning researchers in 4-manifolds.

Wave Scattering in Complex Media: From Theory to Applications

Wave Scattering in Complex Media: From Theory to Applications PDF Author: Bart A. van Tiggelen
Publisher: Springer Science & Business Media
ISBN: 9401002274
Category : Technology & Engineering
Languages : en
Pages : 637

Get Book Here

Book Description
A collection of lectures on a variety of modern subjects in wave scattering, including fundamental issues in mesoscopic physics and radiative transfer, recent hot topics such as random lasers, liquid crystals, lefthanded materials and time-reversal, as well as modern applications in imaging and communication. There is a strong emphasis on the interdisciplinary aspects of wave propagation, including light and microwaves, acoustic and elastic waves, propagating in a variety of "complex" materials (liquid crystals, media with gain, natural media, magneto-optical media, photonic and phononic materials, etc.). It addresses many different items in contemporary research: mesoscopic fluctuations, localization, radiative transfer, symmetry aspects, and time-reversal. It also discusses new (potential) applications in telecommunication, soft matter and imaging.

Wave Propagation in Random Media

Wave Propagation in Random Media PDF Author: Joseph Bishop Keller
Publisher:
ISBN:
Category : Random dynamical systems
Languages : en
Pages : 46

Get Book Here

Book Description


Theoretical And Computational Acoustics '99, Proceedings Of The 4th Ictca Conference (With Cd-rom)

Theoretical And Computational Acoustics '99, Proceedings Of The 4th Ictca Conference (With Cd-rom) PDF Author: Geza Seriani
Publisher: World Scientific
ISBN: 9814485497
Category : Mathematics
Languages : en
Pages : 160

Get Book Here

Book Description
The ICTCA conference provides an interdisciplinary forum for active researchers in academia and industry who are of varying backgrounds to discuss the state-of-the-art developments and results in theoretical and computational acoustics and related topics. The papers presented at the meeting cover acoustical problems of common interest across disciplines and their accurate mathematical and numerical modelling.The present book collects papers that were presented at the 4th meeting and printed in the Journal of Computational Acoustics. There are about 120 full research articles on various subjects, such as wave propagation theory and numerical modelling, sound propagation, vibrations and noise generation, underwater acoustics, engineering seismology, ultrasonic field synthesis and modelling, as well as computational methods, inverse problems and tomography, shallow water acoustics and environmental/bottom parameter extraction. A CD-Rom is attached that allows readers to browse through articles and print those of interest to them.

Effective Computational Methods for Wave Propagation

Effective Computational Methods for Wave Propagation PDF Author: Nikolaos A Kampanis
Publisher: CRC Press
ISBN: 9780367387723
Category :
Languages : en
Pages : 712

Get Book Here

Book Description
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 computational methods used to describe wave propagation phenomena in selected areas of physics and technology. Featuring contributions from internationally known experts, the book is divided into four parts. It begins with the simulation of nonlinear dispersive waves from nonlinear optics and the theory and numerical analysis of Boussinesq systems. The next section focuses on computational approaches, including a finite element method and parabolic equation techniques, for mathematical models of underwater sound propagation and scattering. The book then offers a comprehensive introduction to modern numerical methods for time-dependent elastic wave propagation. The final part supplies an overview of high-order, low diffusion numerical methods for complex, compressible flows of aerodynamics. Concentrating on physics and technology, this volume provides the necessary computational methods to effectively tackle the sources of problems that involve some type of wave motion.