MIXING WINDOWS IN DISCONTINUOUS CAVITY FLOWS

The presence of islands, in particular those generated by P-1 points, are major obstacles to chaotic mixing. We study discontinuous cavity flow mixing systems, where the form of P-1 orbits are known as a combination of two segments of streamlines caused by the motion of the top and bottom walls, respectively. P-1 islands are born and collapse periodically with increasing alternating period of the walls, leaving mixing windows in between where nearly global chaos and hence, uniform mixing takes place.