Physical Oceanography, Vol. 13, No. 5, 2003
ANALYSIS OF OBSERVATIONS AND METHODS FOR CALCULATING
HYDROPHYSICAL FIELDS IN THE OCEAN
HYDROACOUSTIC FIELD OF A POINT SOURCE IN AN INHOMOGENEOUS
MARINE MEDIUM CONTAINING A CYLINDRICAL BODY FLOATING
ON THE SURFACE
Yu. I. Papkova, S. O. Papkov, and A. A. Yaroshenko
We study the problem of determination of the sound field of a point harmonic source in the coas-
tal zone and the influence of a cylindrical body floating above the source on the sound field
formed in the marine medium. A numerical-analytic method is proposed for the determination of
the velocity potential. According to this method, the unknown coefficients in the general solution
of the problem are determined from the corresponding infinite system of linear algebraic equa-
tions by the method of reduction. We present results of numerical calculations for a special case
of a waveguide whose parameters are typical of the coastal part of the sea and perform the com-
parative analysis of the data obtained as a result of variation of the indicated parameters.
The process of development of natural resources in the shelf zone of the World Ocean is now fairly exten-
sive. Therefore, the investigation of the physical processes and phenomena occurring in this region is of signifi-
cant interest not only from the viewpoint of oceanology but also for many other fields of science. As one of di-
rections in the complex analysis of this problem, one can mention the investigation of sound fields formed in
geophysical waveguides on the continental shelf.
The evaluation of the characteristics of sound fields generated by underwater harmonic sources placed in
geophysical waveguides is a fundamental problem of hydroacoustics. Parallel with the construction of exact so-
lutions, problems of this sort are also solved by using various numerical and numerical–analytic methods [1–3].
In this case, it is necessary to determine the space structure of the sound field and its amplitude–frequency char-
acteristic. It is also of interest to study the effect of the profile of sound velocity (in the first approximation, of its
refraction term) on the structure of excited sound fields. As a rule, the analysis of the wave fields in waveguides
whose boundaries are not plane-parallel or including local inhomogeneities in the form of solid bodies placed in-
side the waveguide is based on the use of numerical methods.
The problem of diffraction of waves by a cylinder is studied in , where the methods of the theory of infi-
nite systems of linear algebraic equations are used to obtain its numerical–analytic solution.
In what follows, we consider the problem of finding the sound field induced by a point harmonic source
placed under a perfectly rigid cylinder located on the surface of a waveguide (Fig.
1). It is assumed that the field
of sound velocity includes only the refraction term c
In the present work, the velocity potential is represented as the sum of propagating and standing normal
modes with unknown coefficients. The validity of boundary conditions imposed on the horizontal walls of the
waveguide is guaranteed in constructing the general solution.
Sevastopol National Technical University, Sevastopol. Translated from Morskoi Gidrofizicheskii Zhurnal, No.
ber–October, 2003. Original article submitted January 24, 2002; revision submitted March 25, 2002.
266 0928-5105/03/1305–0266 $25.00 © 2003 Plenum Publishing Corporation