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Old 10-11-2013, 07:26 PM   #8 (permalink)
aerohead
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vorticity

Quote:
Originally Posted by Flakbadger View Post
Fascinating video, but I have to say that birds are limited in the speed at which they can fly---With a few exception (like falcons), they do not travel past 100 miles per hour. Birds that do (again, falcons) have stiffer feathers on many of the wing surfaces.

Airplanes can and do, quite regularly, fly at high speed. The bird's wing is more efficient in many ways, and lots of small flaps (or feathers) will regulate its stability, but it seems likely to me that it wouldn't be as effective at high speed or might even be detrimental.

My "logic" is that if you coated the back surface of a car with flaps, they would create small vortices that would add up to a very large drag coefficient. Am I wrong?
Vorticity is circulation and circulation costs more than laminar flow.So yes,it would be a penalty.Someone would have to finance a study to actually quantify the magnitude of the loss.
Gentoo penguins have been measured at Cd 0.07.If they were 'sanded down' and covered in a smooth painted automotive finish,they might measure Cd 0.04.
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