Vortex Sheet Computations: Roll-Up, Wakes, Separation

Chorin's vortex blob method has been proposed as a way to extend vortex sheet motion past the singularity formation time, into the physically important roll-up regime. Basic questions are: 1. Does the vortex blob method converge to an infinite spiral as the smoothing parameter tends to zero? 2. Do vortex blob computations approximate real fluid motion? This paper will present and discuss three computations which are relevant to these issues: a) periodic roll-up, b) wake patterns in a thin soap film, c) separation at a sharp edge.