Author: J. Robert FrickePublisher:
ISBN:
Category : Ice
Languages : en
Pages : 1042
Book Description
Acoustic Scattering from Elastic Ice
Author: J. Robert FrickePublisher:
ISBN:
Category : Ice
Languages : en
Pages : 1042
Book Description
Three-dimensional Acoustic Scattering from Arctic Ice Proturberances
Author: Tarun Kishore KapoorPublisher:
ISBN:
Category :
Languages : en
Pages : 392
Book Description
Acoustic Diffraction from a Semi-Infinite Elastic Plate Under Arbitrary Fluid Loading with Application to Scattering from Arctic Ice Leads
Author: Peter Hans DahlPublisher:
ISBN:
Category : Scattering (Physics)
Languages : en
Pages : 156
Book Description
The problem of a low-frequency acoustic plane wave incident upon a free surface coupled to a semi-infinite elastic plate surface, is solved using an analytic approach based on the Wiener-Hopf method. By low-frequency it is meant that the elastic properties of the plate are adequately described by the thin plate equation. The diffraction problem relates to issues in long range sound propagation through partially ice-covered Arctic waters, where open leads on the surface represent features from which acoustic energy can be diffracted or scattered. This work focusses on ice as the material for the elastic plate surface, and the results and conclusions are directed toward the ice lead diffraction process. An exact solution to a canonical problem is derived first: a plane wave incident upon a free surface (Dirichlet boundary condition) coupled to a perfectly rigid surface (Neumann boundary condition). Ice material properties are addressed using the locally reacting approximation for the input impedance of an ice plate. This is followed by use of the thin plate equation to describe the input impedance which incorporates elements of elastic wave propagation. An important issue in working with the thin plate equation is the fluid loading pertaining to sea ice and low-frequency acoustics, using an approximation to the exact kernel of the Wiener-Hopf functional equation allows one to proceed to a complete and readily interpretable solution for the far field diffracted pressure.
Scattering of Acoustic and Elastic Waves by Surfaces of Arbitrary Shape
Author: Robert Peter BanaughPublisher:
ISBN:
Category : Elastic waves
Languages : en
Pages : 196
Book Description
Computational Ocean Acoustics
Author: Finn B. JensenPublisher: Springer Science & Business Media
ISBN: 1441986782
Category : Science
Languages : en
Pages : 808
Book Description
Senior level/graduate level text/reference presenting state-of-the- art numerical techniques to solve the wave equation in heterogeneous fluid-solid media. Numerical models have become standard research tools in acoustic laboratories, and thus computational acoustics is becoming an increasingly important branch of ocean acoustic science. The first edition of this successful book, written by the recognized leaders of the field, was the first to present a comprehensive and modern introduction to computational ocean acoustics accessible to students. This revision, with 100 additional pages, completely updates the material in the first edition and includes new models based on current research. It includes problems and solutions in every chapter, making the book more useful in teaching (the first edition had a separate solutions manual). The book is intended for graduate and advanced undergraduate students of acoustics, geology and geophysics, applied mathematics, ocean engineering or as a reference in computational methods courses, as well as professionals in these fields, particularly those working in government (especially Navy) and industry labs engaged in the development or use of propagating models.
Scientific and Technical Aerospace Reports
Author: Ice Statistics and Acoustic Scattering in the Arctic Basin
Author: R. R. GreenePublisher:
ISBN:
Category :
Languages : en
Pages : 41
Book Description
Acoustic propagation in the Arctic is intimately related to the structure of surface pack ice. In this paper, reflection loss and transmission loss are calculated based upon statistical models of ice roughness. Statistical models of ice ridges are introduced and techniques for estimating the roughness spectrum of ridged surfaces are developed. Next, a model for estimating the mean reflection loss is introduced. The reflection loss formulas are based on the statistical models for roughness. Transmission loss calculations using High-Angle parabolic equation (ARCHAPE) in a simulated Arctic environment are compared with data. The results demonstrate that rough surface scattering from random-depth ice keel structures can account for the observed rate of transmission loss in the Arctic. Keywords include: Acoustic Scattering, and Propagation loss.
Underwater Scattering and Radiation
Author: Allan D. PiercePublisher: Academic Press
ISBN: 1483257762
Category : Technology & Engineering
Languages : en
Pages : 395
Book Description
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.
Acoustic Scattering from Elastic Spherical and Cylindrical Shells
Author: William Harley FenderPublisher:
ISBN:
Category : Sound
Languages : en
Pages : 132
Book Description
A Calculation of the Acoustic Shear Wave Attenuation in Sea Ice
Author: J. G. HansePublisher:
ISBN:
Category : Sea ice
Languages : en
Pages : 42
Book Description
The attenuation of an acoustic disturbance propagating in a medium which is not perfectly elastic, homogeneous and isotropic can be considered to be the result of energy dissipation due to classical processes and scattering. The contribution of each of these mechanisms is dependent upon the frequency of the sound wave. In this report several mathematical models are discussed for a transverse wave moving in a visco-elastic material and a scattering theory is developed. The theory is applied to sea ice and attenuation as a function of frequency is predicted for this material. (Author).