from the Guardian:
"Exactly why the tubercles work is not fully understood; there may be more than one reason. Those who've studied the bumps agree that somehow they delay "separation" - the fateful turbulence that is associated with stall.
A key seems to be the difference in pressure between the air rushing over the tubercles and the air channelled through the "troughs" in between."
Wolfgang might be going in this direction with his funny fins?
Scientists Tap Motion in the Ocean for Energy - MSNBC, July 21st, 2008![]()
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Might be worth trying out on an old fin.. grab a triangular file and make yourself some tubercles!
The benefits of this design are at the high left end of the spectrum when the fin is about to stall.It is unlikely that speed fins would suffer from stall but it might have an application on formula fins. Its interesting though that there are no test results provided on the website at all. Not even a graph that I could find.
I thought it was a hoax when I saw the guy's name was Dr Frank E Fish!
But the patent seems to check out.![]()
Came across the original article years ago.
At speed AOAs drag is slightly higher. As Mal says most of the benefit is in delaying stall by the formation of vortices. Works for windmills because they don't have to worry about weed stuck in the hollows of the leading edge.
I think the America's cup boat Stars and Stripes had a film made by 3M that was like shark skin on the hull.
Had a look at the whale fin's leading edge on the link, and then had another look at the leading edge of the first 50 knot fin.