2 edition of **Application of modified ray theory to underwater sound propagation** found in the catalog.

Application of modified ray theory to underwater sound propagation

E. L. Murphy

- 150 Want to read
- 12 Currently reading

Published
.

Written in English

**Edition Notes**

Statement | E.L. Murphy, J.A. Davis and J.A. Doutt. |

Series | Reference -- 71-49., Reference (Woods Hole Oceanographic Institution) -- no. 71-49. |

Contributions | Davis, J. A., Doutt, J. A. |

ID Numbers | |
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Open Library | OL15183734M |

Genetic Risk for Alzheimer’s Disease Traced to Links Between Microglial Cells and Amyloid-β Plaques Audrey Herrald ’23, Medical Sciences, 4/18/ Microglia cluster around amyloid-beta plaques in Alzheimer’s Disease; Microglia (red, Iba1 for mouse and CD11b for human) can be found closely associated with amyloid-beta plaques (methoxy, blue) in APP/PS1 mice as well human AD patients. Applications of Signals and Systems Fall Application Areas Control Communications Signal Processing Control Applications Industrial control and automation (Control the velocity or position of an object) Examples: Controlling the position of a valve or shaft of a motor Important Tools: Time-domain solution of differential equations Transfer function (Laplace Transform) Stability.

Underwater acoustics. Subject: Sound – Transmission – Measurement. Comments: Underwater sound propagation is the factor that makes underwater acoustics so variable and interesting. This is a good tutorial without the math and details. Includes sound propagation, deep sound channel, convergence zones, reliable acoustic path and more. Efficient modelling of mid to high frequency underwater acoustic propagation. Ray theory based acoustic propagation models have been in use for many years and are described in most standard text-books on underwater acoustics. These models have utility at.

Underwater acoustics is the study of the propagation of sound in water and the interaction of the mechanical waves that constitute sound with the water, its contents and its boundaries. The water may be in the ocean, a lake, a river or a l frequencies associated with underwater acoustics are between 10 Hz and 1 propagation of sound in the ocean at frequencies lower than Shallow water ducts. Arctic half-channel. Coherence. Propagation II - Mathematical models (part one). Background. Theorectical basis for propagation modeling: wave equation-- Classification of modelling techniques. Ray theory models: Basic theory-- Caustics-- Gaussian beam tracing-- Range dependence-- Arrival structure-- Beam displacement.

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In this way, modified ray analysis covers a wide class of realistic profiles pertinent to underwater sound propagation.

Modified ray analysis is most conveniently formulated as wavelength‐dependent “ray displacement” and “leakage” phenomena. Ranges for displaced rays Author: E. Murphy, J.

Davis, J. Doutt. At frequencies of a few hundred hertz or less, diffraction effects can be significant for sound propagation in the oceans. A modified ray representation for some of these effects has recently been developed [Murphy, J. Acoust. Soc. Amer. 47, – ()—unbounded problem; Davis and Murphy, this A.

meeting—boundary problem].The method applies to propagation through Author: E. Murphy, J. Davis, J. Doutt. adshelp[at] The ADS is operated by the Smithsonian Astrophysical Observatory under NASA Cooperative Agreement NNX16AC86AAuthor: E.

Murphy, J. Davis, J. Doutt. Ray, a ray tracing program developed by the author, for modeling underwater acoustic propagation with moderately range-varying bathymetry over layered bottom with a thin fluid sedimentary layer over a solid half with arbitrary geo-acoustic properties.

In book: Modeling and Measurement Methods for Acoustic Waves and for Acoustic Microdevices (pp) Chapter: Ray Trace Modeling of Underwater Sound Propagation. The trajectory of sound rays in a model of the ocean with transverse flow is considered using the adiabatic invariant method and the transverse drift of a ray with respect to the main propagation.

A sound propagation model based on modified ray theory is presented in this chapter. The model is applicable to a range independent environment where a water column with an arbitrary sound speed profile overlies a homogeneous, lossy sea bottom. An efficient algorithm for eigen-ray finding is developed, based on which a propagation model is.

Ray theory, in spite of its approximate nature, is a very effective method for the study of sound propagation at sufficiently high frequencies in inhomogeneous media such as the ocean. In this chapter we derive the basic equations of ray acoustics and give their solutions for a stratified ocean.

The tracing out of sound paths in water is known as ray theory and is governed by Snell's Law. Various unique propagation paths can be identified according to the thermal structure of the water, but in practice such paths are a complex combination of simpler structures.

HELSINKI UNIVERSITY ABSTRACT OF THE OF TECHNOLOGY MASTER’S THESIS Author: Sami Kiminki Name of the thesis: Sound Propagation Theory for Linear Ray Acoustic Modelling Date: March 7, Number of pages: +14 Department: Computer Science and Engineering Professorship: T Supervisor: Professor Lauri Savioja Instructor: Tapio Lokki, (Tech.) In this work, a linear ray.

The beam-displacement ray-mode theory is used to analyze the effect of thermocline on underwater sound propagation. The peculiarity of this method is that the boundary effects on the sound field can be expressed by the equivalent boundary reflection coefficient.

Among the main trends in underwater acoustics research and development are underwater sound propagation modeling involving mode theory, parabolic equations [16], and finite element methods to include realistic range dependence and surface and bottom effects, reverberation studies, and ambient noise source and directivity studies [17], as also.

This chapter discusses initial and boundary conditions in propagation models. A number of propagation models such as ray tracing, normal mode theory, or the fast-field program can be used to generate the starting field.

However, for many applications, it is sufficient to approximate the initial field by a. An Introduction to Acoustics S.W. Rienstra & A. Hirschberg Eindhoven University of Technology 28 Nov This is an extended and revised edition of IWDE Comments and corrections are gratefully accepted.

This ﬁle may be used and printed, but for personal or educational purposes only. c S.W. Rienstra & A. Hirschberg This book pro- vides an up-to-date introduction to the theory of sound propagation in the ocean, with much new material having been added throughout the second edition.

It includes both ray and wave treatments and considerable attention is paid to stochastic problems such as the scattering of sound at rough surfaces and random inhomogeneties. Basic laws of ray theory/geometric optics. The basic laws of ray theory are quite self-explanatory.

In a homogeneous medium, light rays are straight lines. Light may be absorbed or reflected; Reflected ray lies in the plane of incidence and angle of incidence will be equal to the angle of reflection.

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The Wave Theory of Sound Excerpts from Chapter 1 of Acoustics: An Introduction to Its Physical Principles and Applications by Allan D. Pierce (published by the Acoustical Society of America) Acoustics is the science of sound, including its production, transmission, and effects. In present usage.

Interactive Sonar Ray Tracing Utility Show below is sound ray tracing utility which plots the expected path of sound waves as they propagate underwater. The path taken by sound propagating underwater is determined by reflection at the surface and ocean bottom and in between by refraction or bending which results from the variation in sound speed as a function of depth.

The Propagation of sound. Sound is a sequence of waves of pressure which propagates through compressible media such as air or water. (Sound can propagate through solids as well, but there are additional modes of propagation). During their propagation, waves can be reflected, refracted, or attentuated by the medium.

In this paper, the new ray equations are used to compute 3-D ray paths for underwater sound propagation from Heard Island to Ascension Island.

A measured sound .in SVP. Previous studies have shown that internal waves can significantly affect the propagation of underwater sound, the magnitude and type of effect are dependent on a range of factors such as frequency, water depth, seabed properties, and the direction of propagation relative to the wave crests (Flatte and Tappert, ; Zhou.

et al.Seismology and the Earth’s Deep Interior Body Waves and Ray Theory Basic principlesBasic principles • Ray definition Rays are defined as the normals to the wavefront and thus point in the direction of propagation. • Rays in smoothly varying or not too complex media Rays corresponding to P or S waves behave much as light does in materials.