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        Discussion Boundary layer drag

#1 Curare Apr 09, 2008 10:20 PM

Boundary layer drag
 
Here's a thought (happened while I was on the can)...

We're dealing with really low RE's, and I'm just wondering whether there is any benefit in going for a slighty rougher finish on our aircraft to reduce boundary layer drag.

Has anyone got any ideas whether I'm barking up the wrong applecart?

Perhaps using mylars isn't the best way to get the most out of our wings.

#2 annihilator Apr 09, 2008 10:42 PM

rougher surfaces will cause the boundary layer to transition from laminar to turbulent quicker, thus increasing drag. You are probably thinking about golf balls and other items called "bluff bodies" that experience a drag reduction by adding roughness. roughness is added to trip the BL into being turbulent, where in the case of a golf ball it decreases drag by tripping to turbulent BL which stays attached longer, and in the case of a sailplane wing can eliminate laminar separation bubbles which are generally bad. So in the case of DLG wing laminarBL=good.

#3 Curare Apr 10, 2008 01:07 AM

righto!


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