Mathematical Digest

Short Summaries of Articles about Mathematics
in the Popular Press

"Dangerous Wake," by Sid Perkins. Science News, 22 June 2002, page387.

The effect of vortices that form on an aircraft's wing tips is one of thefactors that affect spacing between aircraft, which in turn affects importantissues like scheduling. Perkins writes of recent mathematical modeling of thevortices and how they react to wind shear. These vortices "can trail behind anaircraft for more than 30 kilometers," and within a vortex, air can swirl at upto 100 meters per second. The research, by Phillip Saffman and David J. Hill,is published in the July 8 Proceedings of the Royal Society of London A.

--- Mike Breen

American Mathematical Society