CHAOTIC ADVECTIONS FOR STOKES FLOWS IN CIRCULAR CAVITY

Steady Stokes flows in a circular cavity is analytically solved by usi ng Green's function. The familiar phenomenon of Lagrangian chaos for S tokes flows in a long, circular cylinder filled with a viscous fluid s ubject to various boundary conditions is studied numerically, To achie ve chaotic mixing for the fluid particles, two mobile outer walls in c lose contact with a fixed inner wall that have two corresponding openi ngs are made to (independently) oscillate periodically in time, The ex pansion rate for a thin fluid filament Is also determined when the osc illatory modulation is turned on. Our study shows that counterrotating boundaries have a greater tendency to create mixing than corotating o nes.