Forums > Windsurfing   Gps and Speed talk

whale fins?

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Created by choco > 9 months ago, 18 Aug 2008
choco
SA, 4175 posts
18 Aug 2008 7:17PM
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http://www.whalepower.com/drupal/

oldie
VIC, 356 posts
22 Aug 2008 5:14AM
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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?

555
892 posts
22 Aug 2008 5:45AM
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Scientists Tap Motion in the Ocean for Energy - MSNBC, July 21st, 2008

Might be worth trying out on an old fin.. grab a triangular file and make yourself some tubercles!

TimeMachine
89 posts
22 Aug 2008 7:17PM
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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.

lao shi
WA, 1338 posts
22 Aug 2008 9:04PM
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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.

Mobydisc
NSW, 9029 posts
23 Aug 2008 6:34AM
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lao shi said...

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.



Sure it isn't Frankenfurter?

Sharks have fins too and they don't have many bumps on them. They say sharks have been around for a long time so you'd reckon if bumps on fins was a good idea then the baby sharks with little bumps would have been more successful at swimming than baby sharks without bumpy fins and all that jazz. Thats if you believe in natural selection.

If it works then thats great and hopefully it will make all sorts of foils more efficient.





yoyo
WA, 1646 posts
26 Aug 2008 2:30PM
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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.

OceanBlue64
VIC, 980 posts
26 Aug 2008 5:57PM
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Mobydisc said...

lao shi said...

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.



Sure it isn't Frankenfurter?

Sharks have fins too and they don't have many bumps on them. They say sharks have been around for a long time so you'd reckon if bumps on fins was a good idea then the baby sharks with little bumps would have been more successful at swimming than baby sharks without bumpy fins and all that jazz. Thats if you believe in natural selection.

If it works then thats great and hopefully it will make all sorts of foils more efficient.




Actually sharks have many small 'bumps' called dermal denticles or placoid scales. I gather the scales help them swim faster etc etc. I am sure that on the leading edge of their fins, if you looked close enough, you would see 'bumps'.
Here is a neat pic of the sharks skin magnified.
http://nothingtoxic.blogspot.com/2007/02/shark-skin-magnification-x70.html

I have also heard that the US navy has been trying some special coating that mimics the sharks skin, on ships that allows them to reduce friction in the water.

choco
SA, 4175 posts
26 Aug 2008 5:46PM
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I think the America's cup boat Stars and Stripes had a film made by 3M that was like shark skin on the hull.

Ian K
WA, 4155 posts
27 Aug 2008 9:28AM
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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.



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"whale fins?" started by choco