MINIATURE whirlwinds created by the beating of their wings help insects hover
and fly, according to Jane Wang, a physicist at Cornell University in New York
state. Insect flight has long been a puzzle鈥攊n the 1970s scientists tried
and failed to explain how dragonflies kept aloft.
But now, using a complex computer model that simulates the airflow around
dragonfly wings, Wang found that vortices were 鈥渧ery important in most
hovering鈥�. 鈥淚t helps them get lift, thrust to turn, and manoeuvre,鈥� she says.
Vortices are unimportant in helping planes to fly. But to an insect鈥檚 wing, air
is viscous and the inertia of air molecules creates a significant force, Wang
told a meeting of the American Physical Society in Minneapolis last week.