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Old 02-21-2008, 09:16 PM   #6 (permalink)
trebuchet03
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Quote:
Originally Posted by MetroMPG View Post
AWESOME writeup. Thanks for posting that.

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Here's a question: Is there a simple answer as to why introducing a small amount of turbulence in the boundary layer (ahead of the area where flow would normally separate) moves the separation point further downstream & reduces the size of the wake?

Or does that fall into the category of thinking up questions to ask god? :P
Fuzzy is pretty close... So yes, it's called "energizing the boundary layer." Viscous friction slowly increases the thickness of the boundary layer. When this happens, think of an ocean wave crashing over itself and in the case of air, it's making an eddy.

So the simple answer is - you're taking some fast moving energetic air and sweeping it into the slow boundary layer to give it a little kick.

Keep in mind that the type of turbulence we're introducing isn't like the rolling eddies off of a car (or semi truck), it's tiny little ones
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