View Single Post
Old 12-13-2011, 07:18 PM   #44 (permalink)
aerohead
Master EcoModder
 
aerohead's Avatar
 
Join Date: Jan 2008
Location: Sanger,Texas,U.S.A.
Posts: 16,272
Thanks: 24,394
Thanked 7,363 Times in 4,763 Posts
winglets

On the aircraft,the winglet helps spoil the flow over the tip just as tip feathers on soaring birds for which their inspiration is derived.By helping to kill the wingtip vortices,small planes can safely fly at a certain separation distance behind the larger craft.Otherwise,they can litteraly fall from the sky as in a micro-burst downdraft.
On cars,as long as airstreams are converging at different velocities,they're going to spin up into vortices.The vertical projection can wall the two streams off from one another,but once past the fin the disparate velocities will cause the vortice to begin there,unless the flow is already separated.
I think in the case of the pseudo-Jaray rooflines,the only real fix is to stuff the wake full of a proper K-form roof section.
Only these can allow stream mixing without vorticity.
  Reply With Quote