Acoustics of Layered Media II - Point Sources and Bounded Beams, second, updated and enlarged edition

Brekhovskikh, Leonid M.

doi:10.1016/s0218-396x(00)00027-3

Cited by 61 publications

(194 citation statements)

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“…Methods based on the geometrical acoustics have been supplemented by full-wave approaches (Brekhovskikh and Godin, 1999), including a normal-mode theory for range-dependent and horizontally inhomogeneous waveguides.…”

Section: Approachmentioning

confidence: 99%

“…Infragravity waves are surface gravity waves with periods from ~0.5 to ~50 minutes. Infragravity waves are refracted by ocean currents and, especially, by seafloor bathymetry and can be treated in horizontally inhomogeneous ocean using the vertical modeshorizontal rays theory [see, e.g., (Brekhovskikh and Godin, 1999)]. The 3-D HWT algorithm was used to simulate horizontal structure of infragravity wave fields and interpret observations of seafloor pressure fluctuations .…”

Section: Work Completedmentioning

confidence: 99%

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Dynamics and Stability of Acoustic Wavefronts in the Ocean

Godin¹

2014

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LONG-TERM GOALS• To develop a method of modeling sound propagation in an environment with multi-scale inhomogeneities, which preserves the efficiency and intuitive qualities of the ray theory but is free from spurious environmental sensitivity and strong perturbations associated with ray trajectories.• To investigate and quantify effects on underwater acoustic wavefronts of internal gravity waves, sea swell, "spice," and other small-scale processes in the water column. OBJECTIVES1. To assess significance of time dependence of the sound speed and flow velocity perturbations on predictability of acoustic wavefronts and timefronts.2. To quantify horizontal refraction of sound by random meso-scale inhomogeneities at O(1)Mm propagation ranges.3. To find the variance and bias of random ray travel times in the regime, where the ray displacement may be comparable to the vertical extent of the underwater waveguide but the clustering has not developed yet.4. To determine, using a perturbation theory and numerical simulations, typical propagation ranges where clustering of chaotic rays replaces the anisotropy of ray scattering as the main physical mechanism responsible for acoustic wavefront stability.5. To develop an efficient technique for modeling acoustic wavefronts and their perturbations in range-dependent and horizontally inhomogeneous oceans.6. To model perturbations of acoustic wavefronts and timefronts by internal gravity waves, internal tides, sea swell, and "spice" in the ocean.7. To investigate implications of wavefront stability on the downward extension of acoustic timefronts and deepening of lower turning points of steep rays due to small-and meso-scale physical processes in the upper ocean.

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Section: Approachmentioning

confidence: 99%

Section: Work Completedmentioning

confidence: 99%

Dynamics and Stability of Acoustic Wavefronts in the Ocean

Godin¹

2014

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“…However, the ASA is usually limited to the prediction of free space wave propagation and does not include the reflection and transmission of acoustic waves in layered media [13][14][15] or only accounts for periodically layered media [16] or first-order reflections [9,17] which is inadequate when investigating resonance effects and standing wave formation in arbitrary systems. When the ASA is used to calculate transmission and reflection, the method of steepest descent is typically applied to evaluate an integral on a complex contour [18]. This requires analytical knowledge of the reflection-and transmission coefficients.…”

Section: Introductionmentioning

confidence: 99%

Simulation of acoustic fields in fluid-, solid- and porous layers by the combined transfer matrix/angular spectrum approach with applications in bioacoustics

et al. 2015

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“…where V, W are Fresnel reflection and transmission coefficients [11] V ¼ mk z1 Àk z2 mk z1 þ k z2 (8) Similarly as in Ref. [3], three horizontal wave number regimes are considered depending on the nature of the waves: The acoustic power flux J a into air can be calculated by integrating the normal component of the acoustic power flux density Reðp n v z Þ=2 over the interface z ¼0, where the asterisk denotes complex conjugate.…”

Section: Introductionmentioning

confidence: 99%