scholarly journals Improved energy‐flux model for predicting range‐averaged propagation loss in deep water

1977 ◽  
Vol 62 (S1) ◽  
pp. S20-S20
Author(s):  
Ian A. Fraser
Keyword(s):  
Energy Flux ◽  
Deep Water ◽  
Propagation Loss ◽  
Flux Model

Comparison of Sound Propagation Characteristic between Deep and Shallow Water

2014 ◽  
Vol 577 ◽  
pp. 1198-1201
Author(s):  
Zhang Liang ◽  
Chun Xia Meng ◽  
Hai Tao Xiao
Keyword(s):  
Shallow Water ◽  
Deep Water ◽  
Sound Speed ◽  
Sound Propagation ◽  
Spherical Wave ◽  
Sound Field ◽  
Propagation Loss ◽  
Speed Profile ◽  
Sound Speed Profile ◽  
Propagation Law

The physical characteristics are compared between shallow and deep water, in physics and acoustics, respectively. There is a specific sound speed profile in deep water, which is different from which in shallow water, resulting in different sound propagation law between them. In this paper, the sound field distributions are simulated under respective typical sound speed profile. The color figures of sound intensity are obtained, in which the horizontal ordinate is distance, and the vertical ordinate is depth. Then we can get some important characteristics of sound propagation. The results show that the seabed boundary is an important influence on sound propagation in shallow water, and sound propagation loss in deep water convergent zone is visibly less than which in spherical wave spreading. We can realize the remote probing using the acoustic phenomenon.

Further Validation and Implementation of an Algebraic Energy Flux Model for High Speed Gaseous Shear Flows

2022 ◽  
Author(s):  
Casey Broslawski ◽  
Bryan Morreale ◽  
Rodney D. Bowersox ◽  
Gary Nicholson ◽  
Lian Duan
Keyword(s):  
Energy Flux ◽  
High Speed ◽  
Shear Flows ◽  
Flux Model

Calibration of an energy flux model over bare soils during the HAPEX-MOBILHY experiment

1992 ◽  
Vol 58 (3-4) ◽  
pp. 257-283 ◽  
Author(s):  
M.Ben Mehrez ◽  
O. Taconet ◽  
D. Vidal-Madjar ◽  
Y. Sucksdorff
Keyword(s):  
Energy Flux ◽  
Flux Model ◽  
Bare Soils

On the rapidity spectrum of the energy flux model

1975 ◽  
Vol 14 (5) ◽  
pp. 153-157
Author(s):  
G. Calucci
Keyword(s):  
Energy Flux ◽  
Flux Model ◽  
Rapidity Spectrum

Energy-flux model of seismic coda: Separation of scattering and intrinsic attenuation

1987 ◽  
Vol 77 (4) ◽  
pp. 1223-1251
Author(s):  
Arthur Frankel ◽  
Leif Wennerberg
Keyword(s):  
Decay Rate ◽  
Energy Flux ◽  
Single Scattering ◽  
Coda Q ◽  
Scattering Attenuation ◽  
Seismic Coda ◽  
Wide Range ◽  
Flux Model ◽  
Strong Scattering ◽  
Q Values

Abstract A new model of seismic coda is presented, based on the balance between the energy scattered from the direct wave and the energy in the seismic coda. This energy-flux model results in a simple formula for the amplitude and time decay of the seismic coda that explicitly differentiates between the scattering and intrinsic (anelastic) attenuation of the medium. This formula is valid for both weak and strong scattering and implicitly includes multiple scattering. The model is tested using synthetic seismograms produced in finite difference simulations of wave propagation through media with random spatial variations in seismic velocity. Some of the simulations also included intrinsic dissipation. The energy-flux model explains the coda decay and amplitude observed in the synthetics, for random media with a wide range of scattering Q. In contrast, the single-scattering model commonly used in the analysis of microearthquake coda does not account for the gradual coda decay observed in the simulations for media with moderate or strong scattering attenuation (scattering Q ≦ 150). The simulations demonstrate that large differences in scattering attenuation cause only small changes in the coda decay rate, as predicted by the energy-flux model. The coda decay rate is sensitive, however, to the intrinsic Q of the medium. The ratio of the coda amplitude to the energy in the direct arrival is a measure of the scattering attenuation. Thus, analysis of the decay rate and amplitude of the coda can, in principle, produce separate estimates for the scattering and intrinsic Q values of the crust. We analyze the coda from two earthquakes near Anza, California. Intrinsic Q values determined from these seismograms using the energy-flux model are comparable to coda Q values found from the single-scattering theory. These results indicate that coda Q values are, at best, measures of the intrinsic Q of the lithosphere and are unrelated to the scattering Q.

A NEW ENERGY-FLUX MODEL OF WAVEGUIDE REVERBERATION BASED ON PERTURBATION THEORY

2010 ◽  
Vol 18 (03) ◽  
pp. 209-225 ◽  
Author(s):  
J. R. WU ◽  
E. C. SHANG ◽  
T. F. GAO
Keyword(s):  
Perturbation Theory ◽  
Shallow Water ◽  
Energy Flux ◽  
Environmental Parameters ◽  
Water Area ◽  
Full Wave ◽  
Shallow Water Area ◽  
New Energy ◽  
Flux Model ◽  
Filtering Approach

The modal shallow water reverberation theory and the energy-flux shallow water reverberation theory were combined to get a new energy-flux model of waveguide reverberation based on Perturbation theory. There are only three environmental parameters (P, Q, μ) in the new reverberation model. It has clear physical picture and it is satisfied the waveguide constraint without any adjustable parameters. The new energy-flux reverberation model was compared with the modal reverberation model (full-wave reverberation model). The results show that the new model can explain the shallow water reverberation in most cases. It is shown that the contributions of parameter P and Q are mutual compensated (coupled) for a fixed reverberation data, therefore it is hard to extract both of them simultaneously. Finally, parameters P and μ at different frequencies were extracted from the reverberation data of "Qingdao-2005 experiment" in Yellow sea shallow-water area where the parameter Q has been extracted from mode filtering approach previously.

Statistics of Internal Tide Bores and Internal Solitary Waves Observed on the Inner Continental Shelf off Point Sal, California

2018 ◽  
Vol 48 (1) ◽  
pp. 123-143 ◽  
Author(s):  
John A. Colosi ◽  
Nirnimesh Kumar ◽  
Sutara H. Suanda ◽  
Tucker M. Freismuth ◽  
Jamie H. MacMahan
Keyword(s):  
Continental Shelf ◽  
Energy Flux ◽  
Solitary Waves ◽  
Internal Tide ◽  
Propagation Loss ◽  
Internal Solitary Waves ◽  
Time Behavior ◽  
Time Duration ◽  
Match Filter ◽  
Inner Continental Shelf

AbstractMoored observations of temperature and current were collected on the inner continental shelf off Point Sal, California, between 9 June and 8 August 2015. The measurements consist of 10 moorings in total: 4 moorings each on the 50- and 30-m isobaths covering a 10-km along-shelf distance and an across-shelf section of moorings on the 50-, 40-, 30-, and 20-m isobaths covering a 5-km distance. Energetic, highly variable, and strongly dissipating transient wave events termed internal tide bores and internal solitary waves (ISWs) dominate the records. Simple models of the bore and ISW space–time behavior are implemented as a temperature match filter to detect events and estimate wave packet parameters as a function of time and mooring position. Wave-derived quantities include 1) group speed and direction; 2) time of arrival, time duration, vertical displacement amplitude, and waves per day; and 3) energy density, energy flux, and propagation loss. In total, over 1000 bore events and over 9000 ISW events were detected providing well-sampled statistical distributions. Statistics of the waves are rather insensitive to position along shelf but change markedly in the across-shelf direction. Two compelling results are 1) that the probability density functions for bore and ISW energy flux are nearly exponential, suggesting the importance of interference and 2) that wave propagation loss is proportional to energy flux, thus giving an exponential decay of energy flux toward shore with an e-folding scale of 2–2.4 km and average dissipation rates for bores and ISWs of 144 and 1.5 W m−1, respectively.

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