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?

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 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.

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.

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.