Vortex structure of swirl flows

The paper presents some results of investigations related to the problem of studying the mechanisms of vorticity generation and the conditions for formation and stability of determinate vortex structures. This problem is one of particular importance in the field of fundamental investigations of complex vortex flows. At the same time the problems of studying the physics and topology of complex vortex and swirl flows are topical for diagnostics of some hazardous geophysical processes such as hurricanes, tornados, tsunami, change in the direction of oceanic currents, etc. It is shown that the main mechanism for appearance of steady-state vortex structures in swirl and curved flows is connected with the process of helicity generation. The equation of helicity generation rate for dynamical liquid system is obtained to determine the critical conditions for flow field alteration. The convenience of theoretical analysis on the base of helicity generation rate equation consists in a possibility to predict the appearance of steady large-scale structures from solution of a single scalar equation written with respect to the scalar value of helicity. Application of developed model of vortex motion in swirl flows is demonstrated for two hydro-mechanical systems: in case of Taylor instability in annular channel, and for flow of coolant in collector of nuclear reactor. The paper describes a new approach for prediction of conditions for appearance of large-scale steady-state vortex structures in complicated vortex and swirl flows.