Chaotic advection in Stokes flow in semicircle

The two-dimensional Stokes flows due to a periodic motion of a circular and rectilinear boundary in a semicircle is considered. An exact analytical of the velocity field is given. The peculiarities of the velocity field and their influence on the motion of dye fluids in these domains are studied. Poincaré sections and trajectories of motion of passive fluid particles are calculated and analyzed for various regimes and values of the boundary velocities. The analysis of Poincaré sections reveals both zones of intensive (chaotic) and weak (regular) mixing of marked passive regions of fluid flow in the semicircle.