Wave and extra-wide-angle parabolic equations for sound propagation in a moving atmosphere

2020 ◽  
Vol 147 (6) ◽  
pp. 3969-3984 ◽  
Author(s):  
Vladimir E. Ostashev ◽  
D. Keith Wilson ◽  
Michael B. Muhlestein
Keyword(s):  
Parabolic Equations ◽  
Sound Propagation ◽  
Wide Angle

scholarly journals Extra-wide-angle parabolic equations in motionless and moving media

2021 ◽  
Author(s):  
Vladimir Ostashev ◽  
Michael Muhlestein ◽  
D. Wilson
Keyword(s):  
Refractive Index ◽  
Parabolic Equations ◽  
Sound Propagation ◽  
Perturbation Technique ◽  
Integral Form ◽  
Spectral Domain ◽  
Wide Angle ◽  
Starting Point ◽  
Spectral Algorithm ◽  
Moving Media

Wide-angle parabolic equations (WAPEs) play an important role in physics. They are derived by an expansion of a square-root pseudo-differential operator in one-way wave equations, and then solved by finite-difference techniques. In the present paper, a different approach is suggested. The starting point is an extra-wide-angle parabolic equation (EWAPE) valid for small variations of the refractive index of a medium. This equation is written in an integral form, solved by a perturbation technique, and transformed to the spectral domain. The resulting split-step spectral algorithm for the EWAPE accounts for the propagation angles up to 90° with respect to the nominal direction. This EWAPE is also generalized to large variations in the refractive index. It is shown that WAPEs known in the literature are particular cases of the two EWAPEs. This provides an alternative derivation of the WAPEs, enables a better understanding of the underlying physics and ranges of their applicability, and opens an opportunity for innovative algorithms. Sound propagation in both motionless and moving media is considered. The split-step spectral algorithm is particularly useful in the latter case since complicated partial derivatives of the sound pressure and medium velocity reduce to wave vectors (essentially, propagation angles) in the spectral domain.

A model for radio propagation loss prediction in buildings using wide-angle parabolic equations

2009 ◽  
Author(s):  
Fatima Nazare Barauna Magno ◽  
Joao Furtado de Souza ◽  
Klaus Cozzolino ◽  
Jesse Carvalho Costa ◽  
Gervasio Protasio dos Santos Cavalcante
Keyword(s):  
Parabolic Equations ◽  
Propagation Loss ◽  
Radio Propagation ◽  
Wide Angle ◽  
Loss Prediction

Simulation of N-wave propagation in turbulent atmosphere using standard and wide-angle parabolic equations

2020 ◽  
Vol 148 (4) ◽  
pp. 2615-2615
Author(s):  
Petr V. Yuldashev ◽  
Maria M. Karzova ◽  
Vera Khokhlova ◽  
Philippe Blanc-Benon
Keyword(s):  
Wave Propagation ◽  
Parabolic Equations ◽  
Turbulent Atmosphere ◽  
Wide Angle ◽  
N Wave

scholarly journals Horizontal Refraction of Acoustic Waves in Shallow-Water Waveguides Due to an Inhomogeneous Bottom Structure

2021 ◽  
Vol 9 (11) ◽  
pp. 1269
Author(s):  
Andrey Lunkov ◽  
Danila Sidorov ◽  
Valery Petnikov
Keyword(s):  
Shallow Water ◽  
Parabolic Equations ◽  
Acoustic Waves ◽  
Sound Propagation ◽  
Transmission Loss ◽  
Three Dimensional ◽  
Transitional Region ◽  
Wave Effect ◽  
Low Frequencies ◽  
Horizontal Refraction

Three-Dimensional (3-D) sound propagation in a shallow-water waveguide with a constant depth and inhomogeneous bottom is studied through numerical simulations. As a model of inhomogeneity, a transitional region between an acoustically soft and hard bottom is considered. Depth-averaged transmission loss simulations using the “horizontal rays and vertical modes” approach and mode parabolic equations demonstrate the horizontal refraction of sound in this region, even if the water column is considered homogeneous. The observed wave effect is prominent at low frequencies, at which the water depth does not exceed a few acoustic wavelengths. The obtained results within the simplified model are verified by the simulations for a real seabed structure in the Kara Sea.

Wide-Angle Mode Adiabatic Parabolic Equations

2002 ◽  
Vol 48 (6) ◽  
pp. 728 ◽  
Author(s):  
M. Yu. Trofimov
Keyword(s):  
Parabolic Equations ◽  
Wide Angle
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