Journal ArticleDOI
Normal‐mode program with both the discrete and branch line contributions
TLDR
In this article, the sound speed and density profiles are partitioned in layers such that in each layer the square of the index of refraction can be approximated by a straight line and the density by a constant.Abstract:
In a stratified ocean model, in which the sound speed and density become constant as the depth coordinate becomes infinite, the pressure field can be represented as a finite sum of modes plus an integral superposition of modes. This later contribution is given by an integration around a branch cut. In this analysis the sound‐speed and density profiles are partitioned in layers such that in each layer the square of the index of refraction can be approximated by a straight line and the density by a constant. The profile is terminated in a high‐speed isovelocity half space. Using this profile, it is possible to express the depth‐dependent portion of the pressure field in terms of Airy functions. Evaluation of the modal and branch line contributions shows that the branch integral can contribute significantly to the pressure field over a range equal to at least one water depth and in some cases to many water depths.Subject Classification: 30.20, 30.25.read more
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Journal ArticleDOI
Estimating the compressional and shear wave speeds of a shallow water seabed from the vertical coherence of ambient noise in the water column
TL;DR: In this article, the vertical directionality and coherence are relatively stable features of the noise that are determined primarily by the seabed, rather than temporal variations in the surface source distribution.
Book ChapterDOI
Numerical Models of Underwater Acoustic Propagation
F. R. DiNapoli,R. L. Deavenport +1 more
TL;DR: In this chapter an attempt is made to summarize those models of propagation loss in the field of underwater acoustics which have been converted into an automated computer code capable of being executed by someone other than the originator for a wide variety of problems.
Journal ArticleDOI
Three-Dimensional Propagation and Scattering Around a Conical Seamount
Wenyu Luo,Henrik Schmidt +1 more
TL;DR: A three-dimensional propagation and scattering model is developed for an offset acoustic source in an ocean with axisymmetric bathymetry that applies a number of modifications to the numerical formulation, leading to orders of magnitude in numerical efficiency for realistic problems.
Journal ArticleDOI
Critical layer singularities and complex eigenvalues in some differential equations of mathematical physics
TL;DR: In this article, the authors identify the nature of these singular layers and complex eigenvalues, and the relationships that exist between the different context in which they are found, and in particular to emphasize the occurrence of and interpretation of complex Eigenvalues in quantum mechanics.
Book ChapterDOI
Theoretical Methods in Ocean Acoustics
TL;DR: In this article, sound propagation in a fluid waveguide is studied, where sound is a small amplitude wavelike disturbance on the hydrodynamic background and the properties of the fluid equations are described.