Wingtip vortices are circular patterns of rotating air left behind a
wing as it generates
lift. One wingtip
vortex trails from the
tip of each wing. Wingtip vortices are sometimes named
trailing or
lift-induced vortices because they also occur at points other than at the wing tips. Indeed, vorticity is trailed at any point on the wing where the lift varies span-wise (a fact described and quantified by the
lifting-line theory); it eventually rolls up into large vortices near the wingtip, at the edge of
flap devices, or at other abrupt changes in
wing planform.