http://www.scienceagogo.com/news/20040412020237data_trunc_sys.shtml
Read some articles by Dr. Frank Fish, I believe he was the main researcher on this stuff. He also holds patents on its application to surfboard fins, as well as much more economically viable products…
So, pressure dents actually are increasing the effeciency of a board?
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So, pressure dents actually are increasing the effeciency of a board?
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No.
Where is the info on him holding the patent on surfboard fins? I searched and found nothing.
LOL. I was just kiddin.
Time to start understanding Reynolds Numbers, having to do with speed, size, fluid viscosity and some other things.
I exchanged a few emails with Dr. Fish when I was working on a project for my “Fluid Mechanics of Biological Systems” class a few years back, did the project on “How tubercles effect performance of whale flippers”. I asked him about its application to surfboard fins, he sent me a photo of fin with the leading edge bumps (tubercles) and told me that it has been tested a bit, but not really fully explored. Relevent US patent # is 6,431,498. I was really tempted to make some fins with the tubercles for personal use and experimentation, but never got around to it… would be a pain in the ass to foil with that fkd up leading edge.
I just took a quick look at that patent, Im no patent lawyer but I guess it some kind blanket patent that applies to the application on tubercles on general lifting surfaces, whether that be a wing, surfboard fin, wind turbine blade etc.
I believe the most promosing application for the research conducted by Dr. Fish and his associates is to wind turbines… LOT more $$ there than in surfing
I have most of the research papers that were written on the subject as of a few years ago if anybody wants them. Send me a PM with your email and I will send it to you. Some really good stuff in those papers.
I like to think about Reynolds # (Re) in a very qualitative way… its basically the ratio of inertial forces to viscous forces. For lower Re, viscous effects are more prevelant and flows are more likely to follow a convex surface and stay attached. At higher Re as the momentum of the flow becomes prevelant, viscous forces are less likely to be able to keep flow attached to convex curves. Of course this is quite a simplification…
“I was really tempted to make some fins with the tubercles for personal use and experimentation, but never got around to it… would be a pain in the ass to foil with that fkd up leading edge.”
I’ve done some. I put the edges on to fins I already had. Foil was there, but it was still some fine work to get 'em nice and smooth. Anyway, it makes a noticeable difference akin to the function of a MVG, as the tubercles perform a similar function in setting up votices and reducing incidence of flow separation at high angles of attack.
“Humpback” center fin. What would this change about say a 7’0" single fin with the same size/rake ‘bumpless’ fin? Doesn’t look like it’s fiberglass, kinda sick though.
Mine are way more tubercled than that… About 1/2" deep and wide at the base and decreasing from there.
Thanks Durbs. Definitely more money in wind turbines than surfboards and fins.