Konstantin Koshel'

In this paper we consider chaotic advection in a barotropic inviscid unidirectional pulsating flow over a point topographic vortex located near a rectilinear boundary. The process of passive markers' transport from the vortical area into the flow-through region is examined. In particular, the evolution of the corresponding Poincaré sections as a function of the frequency of oscillations is studied. The optimal frequency for chaotic mixing caused by an external excitation is calculated. An approach to studying the chaotic advection mechanism and parameters for open systems with finite residence time trajectories is proposed. This approach is based on the distribution of time intervals necessary to carry markers into the flow-through region, and on the Lyapunov exponent, which can be calculated on a finite time interval. A classification of behavior of fluid particle trajectories is obtained by comparing the named parameters. It has been established that as the boundary influence increases, a new type of trajectories with large Lyapunov exponent and residence time occurs.