arXiv subjects

Vasily A. Vakorin

Publications and source records attributed to Vasily A. Vakorin.

4 recordsLinked to original sources

arXiv2005

Internal gravity waves in stratified horizontally inhomogeneous media

The problem of internal gravity waves generation by a point source moving in a stratified medium varying with respect to all spatial variables and time is considered. The fact that the characteristic horizontal scales of density variation may be large as compared with lengths of internal gravity waves makes it possible to solve this problem by means of an approximate method analogous to the WKB method. Therefore, in investigating the problem of internal gravity waves generation by a point source moving in a stratified horizontally inhomogeneous unsteady medium solution for individual mode must be sougth in the form of waves of a special type - Airy and Fresnel waves, where special functions allow to describe internal gravity waves field structure both near and far from individual mode wave front. Then the problem is reduced to the solution of the eikonal equation with some conservation laws perfomed at its characteristics.

math-ph↗

arXiv2005

Critical regimes of internal gravity wave generation

The problem of constructing an asymptotic representation of the solution of the internal gravity wave field exited by a source moving at a velocity close to the maximum group velocity of the individual wave mode is considered. For the critical regimes of individual mode generation the asymptotic representation of the solution obtained is expressed in terms of a zero-order Macdonald function. The results of numerical calculations based on the exact and asymptotic formulas are given.

math-ph↗

arXiv2004

Internal Gravity Waves in a Stratified Fluid with Smoothly Varying Bottom

The far field asymptotic of internal waves is constructed for the case when a point source of mass moves in a layer of arbitrarily stratified fluid with slowly varying bottom. The solutions obtained describe the far field both near the wave fronts of each individual mode and away from the wave fronts and are expansions in Airy or Fresnel waves with the argument determined from the solution of the corresponding eikonal equation. The amplitude of the wave field is determined from the energy conservation law along the ray tube. For model distributions of the bottom shape and the stratification describing the typical pattern of the ocean shelf exact analytic expressions are obtained for the rays, and the properties of the phase structure of the wave field are analyzed.

physics.flu-dyn↗

arXiv2004

Weak Singularity for Two-Dimensional Nonlinear Equations of Hydrodynamics and Propagation of Shock Waves

A system of two-dimensional nonlinear equations of hydrodynamics is considered. It is shown that for the this system in the general case a solution with weak discontinuity-type singularity behaves as a square root of S(x,y,t), where S(x,y,t)>0 is a smooth function. The necessary conditions and series of corresponding differential equations are obtained for the existence of a solution.

math-ph↗