Baroclinic factor in the stirring of waters of a sinking thermal with surrounding fresh water

Abstract

The results of studying the process of stirring of a sinking thermal (small volume of denser water) with surrounding water are presented. The analysis of laboratory flows in a hydroflume has been allowed to identify the main peculiarities of the stirring of the thermal and the surrounding water. The essence of one of these features concluded in the presence of many high-gradient layers in the density field. The phase of an advective-rotational nature of the stirring of thermal waters with different density has been identified. Detailing of the evolution of the flow density structure was performed using the calculated flows on a 2d-nonlinear model of the dynamics of a fluid that is inhomogeneous in density. Features of the density structure are revealed using the values of local density gradients for the internal nodes of the computational grid. The density gradients along and across the streamlines were calculated. Quantitative estimates of the repeatability of high-gradient layers have shown significant variability in the flow density field. An analysis of the potential stability of the selected local regions of the flow has been carried out. The calculation of the Reynolds (Re) and Richardson (Ri) numbers has been allowed to assume a laminar nature of the flow, with the exception of two small zones in the back part of the sinking thermal. The role of the baroclinic mechanism of vorticity generation as a structure-forming factor in the formation of a distinguished stage of advective-vortex movement within interpenetration of thermal with surrounding water has shown.