Quote:
Originally Posted by Logic
My humble apologies; I misread that.
Statically; something 'Too good to be true' that is true... comes along every 30 years. (I like to look for these)
Despite the Cognitive Dissonance these Tubercles have caused in you; you're just going to have to get your head around the idea as the mounting body of evidence proving they work us undeniable and they are being adopted by industry.
Here's Harvard University:
"...Harvard University researchers have come up with a mathematical model that helps explain this hydrodynamic edge.
The work gives theoretical weight to a growing body of empirical evidence that similar bumps could lead to more-stable airplane designs, submarines with greater agility, and turbine blades that can capture more energy from the wind and water.
We were surprised that we were able to replicate a lot of the findings coming out of wind tunnels and water tunnels using relatively simple theory,” says Ernst van Nierop, a PhD candidate at the School of Engineering and Applied Sciences at Harvard. He coauthored the study with mathematics professor Michael Brenner and researcher Silas Alben..."
https://www.technologyreview.com/200...wind-turbines/
My memory is... selective at best. So when I said " Some Aero Engineer" I actually meant:
Frank Fish. A professor of biology at West Chester University.
You can read about how he discovered why whales have evolved these tubercles here:
https://www.theguardian.com/science/...lbehaviour.usa
I too grew up flying (GPL), repairing and building gliders (3 axis) and other small and experimental aircraft.
Winglets to minimize wing tip vortices were the 'talk of the town' back then and I was as surprised as you to learn (or not..?) about these tubercles.
But once you accept that evolution does not evolve things that don't give an advantage and that no matter how much wind tunnel time etc you have under your belt; you will never catch up with the time evolution has had; you may be more open to throwing some of what you thought you knew out the window!
Good luck! 
As for seeing them at the airport:
As usual; there will be a 20 year hiatus while everyone waits for the patents to expire. |
1) Your 'defense' of this technology is very 'telling.'
2) I invite you to revisit 'critical roughness.'
3) I invite you to dig out, from your reference library, the kinematic viscosity of air at standard conditions.
4) Since Rn 100,000 was provided in the research paper, we're free to reverse-engineer the wings velocity.
5) I ran numbers for a Piper Cherokee, with the Clark-Y 'Hershey-Bar' wing with dihedral, 6-foot chord.
6) At Rn 100,000, the aircraft velocity is 15-feet/second ( 10.27-mph )[ 10.129-knots ].
7) For a PORSCHE Taycan, of length= 195.4-inches, I calculated 3.14-mph velocity.
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7) I called my brother to confirm the flight data for the Cherokee we flew out of Van Nuys Municipal Airport, Southern, California.
* Our takeoff speed was 70-mph, @ zero flaps.
* One can nurse the Cherokee off the ground, in ground effect, @ 40-mph,zero flaps, if there are no collision hazards.
* For safety, and guarantee of rudder authority, in the case of a crosswind, or gust, the plane is landed @ 85-mph, on a 30-degree glide path, with 10-30-degrees flap. Reynolds number @ landing = 4,986,666.
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8) The PORSCHE Taycan, @ 100 km/h = Rn 9,887,037.
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9) I invite you to do your own math, with an aircraft and automobile of your own choosing, and see if, in the course of 'normal' flight or driving that, you experience Rn 100,000 for any significant temporal portion of the flight, or drive.
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10) You may also want to visit the SEARCH function over at the Aerodynamics Forum, and see if you can locate the dedicated thread on Humpback Whale tubercles we batted back and forth many years ago.
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11) At the time, Paul T. Soderman of NASA was kind enough to mail me a copy of his ' Aerodynamic Effects of Leading Edge Serrations on a Two-Dimensional Airfoil,' U.S. ARMY Air Mobility R&D Laboratory, Moffett Field, California, NASA Technical Report X-2643, September, 1972.
In this report he cites: ' The silent Flight of Owls, R.R. Graham, Journal of Royal Aeronautical Society, Volume 38, pp 837-843, 1934.
12) In April, 1974, Paul co-authored,' Investigations of Acoustic Effects of Leading-Edge Serrations on Airfoils, along with Alan S. Hersh and Richard E. Hayden, JOURNAL OF AIRCRAFT, Volume 11, No.4, pp 197-2002.
13) It appears that aeronautical engineering interest in bio-mimicry did not begin with whale-fin tubercles. And the research examined phenomena of interest not normally associated with 'aerodynamics.'
14) In the future, I'd appreciate if you address aerodynamic/ fluid mechanic materials at the 'Aerodynamics Forum,' where the SEARCH function can deliver you to our entire corpus.
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