Surface Effects Related to the Flow of a Nonuniformly Stratified Fluid around Obstacles

摘要

Flow around underwater obstacles in a marine medium leads to the generation of perturbations of the physical fields, which evolve and can reach the water surface changing its structure. Investigations of such processes were carried out in a laboratory and in field conditions [ 1, 5]. It was assumed that the stratification of the seawater is generally weak and almost does not influence the deep processes that can reach the surface. However, in the real marine conditions, the water stratification is not uniform and has specific features. We assume that such features can manifest themselves as sharp jumps in the water density caused by the existence of a seasonal pycnocline or other density jumps that appear in the stratified column of seawater. Previously, the authors considered a model of flow around an obstacle in a fluid with a sharply changing density [2]. It is important to compare the mechanisms of the influence of the density interface on the parameters of the surface perturbations in two qualitatively different cases of the obstacle localization in the upper and lower layers of fluid and answer the following question: how significant is the screening effect of the perturbations reaching the surface by the density interface. It is possible to make estimates based on the solution of the formulated problem that have a significant importance in the applied problems, for example, in the monitoring of sea basins.