TITLE:
Caustic Structure of the Under Water Sound Channel
AUTHORS:
Vsevolod Petrovich Ivanov, Galina Kalenikovna Ivanova
KEYWORDS:
Rays; Running Wave; Sound Field; Caustics; Waveguide
JOURNAL NAME:
Open Journal of Acoustics,
Vol.4 No.1,
March
21,
2014
ABSTRACT: Using the ray method, an investigation has been
carried out on the structure of caustics in the wa- veguide assuming the canonical distribution of the sound
velocity with depth. Monochromatic point source of sound was on the axis of the
waveguide. There is considered water rays only. It is
shown that the spatial part of the phase of a running sound wave does not
contain the wave propagation direction and is
always a positive quantity. When the trajectories are calculated, it is assumed that inversion of
rays occurs at an angle of total internal reflection where the reflection
coefficient is equal to unity. This eliminates the horizontal part of the
trajectories. At other points, the reflection coefficient
is assumed to be zero, and the passing coefficient is equal to unity. With this
change in the calculation of ray’s trajectories, the basic structure of the caustics remained the same. It is shown that
the boundary line of the caustic is a number of foci in which rays intersect
with similar angles out of the source and have neighbour times of propagation.
Structure of the sound field along the boundary line of the caustic is
periodic. Its period coincides with the wavelength of the field radiated by the source.