On the Lagrangian transport near oscillating vortex in running flow

Passive particles advection is considered in the vicinity of hyperbolic stationary point of the separatrix destroyed by insteady perturbations. For different frequencies of the disturbancies the trajectories of advected particles are investigated analytically and numerically. The approximate criteria of capture and release of particles are obtained. The results are linked with known law for the stochastic layer width near separatrix. The obtained criteria are connected with analytical Melnikovs integral.