A blinking rotlet model for chaotic advection

The Stokes flow due to a rotlet in a circle is determined. The solution shows that for a certain position of the rotlet, the how has a second stagnation point symmetrically placed inside the circle. Thus, a ''blinking 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 computational investigations of this phenomenon in a cylindrical tank with two rotating cylinders. (C) 1996 American Institute of Physics.