A BLINKING ROTLET MODEL FOR CHAOTIC ADVECTION

The Stokes flow due to a rotlet in a circle is determined. The solutio n shows that for a certain position of the rotlet, the how has a secon d stagnation point symmetrically placed inside the circle. Thus, a ''b linking rotlet'' model can be constructed in which the rotlet that is ''off'' does not disturb the how. This model seems preferable to the ' 'blinking vortex'' flow when discussing chaotic advection by a Stokes how, and is useful for comparisons with recent experimental and comput ational investigations of this phenomenon in a cylindrical tank with t wo rotating cylinders. (C) 1996 American Institute of Physics.