>"Where the leading edge of a plane's wing or nose meets the air flowing
>past it, a thin boundary layer is created. Eddies and whorls in the
>boundary layer produce drag-inducing friction. Scientists [Dr. John Kim
>at U. C. L. A.] have developed tiny microelectromechanical systems, or
>MEMS, to control the drag by canceling the vortices with
>countervortices. The microflaps have sensors that record temperature and
>pressure; they are raised or lowered by miniature mechanisms controled
>by a computer."
This kind of thing has other applications, too: a friend was involved in studies of how dolphins manage to move so smoothly through water. It appears their skin senses and reacts dynamically to turbulence to reduce drag. Replicating the effect seemed too expensive at the time, due to the massive amounts of computation [believed] required.
-+- Sid Maxwell @ Borland, Scotts Valley CA