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'Whale Tubercles" cut drag 32% on wings.
https://i0.wp.com/blog.gridpro.com/w...00%2C359&ssl=1
"Pressure contours and streamlines at α = 10 for NACA 63–021 with straight leading edge and with tubercles. a. Shows mid-chord separation line on the upper part of the conventional wing. b. Shows large vortices downstream of the troughs along the leading edge and laminar attached flow downstream of the tubercles without separation. Images source" https://blog.gridpro.com/a-whale-of-...n-wing-design/ This is for wings, but the increased laminar flow..? Turn the pic 90% and I can see wheels and wing mirrors etc in turbulent troughs... maybe..?? Perhaps the bottom of a car too. More links: https://academic.oup.com/icb/article/51/1/203/636829 https://youtu.be/dz39guNxAc4 |
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CFD NACA airfoil 'separation'
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2) It's a remarkable claim to suggest that there'd be 'separation' as depicted. 3) Any separation, anywhere on a 'real' aircraft would be a 'reach of the imagination', except at burble-point and stall angles of attack. 4) I submit that there's nothing but 'turbulent boundary layer' where they're claiming their so-called 'separation.' 5) I recommend a re-analysis with 'real' industry-grade CFD, plus evidence that this 'modification' is presently operating with FAA certification anywhere on Earth. |
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WhatTH do you mean I'M claiming!? Some Aero Engineer was wandering why whales had these Bumps on the LEADING EDGE of their fins, so he looked for a dead whale and tested a fin. The above is what HE claimed to find and ALL subsequent tests seem to corroborate his results. That explains why people are 1: selling them and 2: buying them. in short: this is what billions of years of EVOLUTION claims to have found a good while before we even invented the wheel! If there's one thing I hucking fate it's people who wipe their arses on other peoples posts/research as a matter of course, without doing any research on the subject of their own! Go find some science that refutes this I dare ya!! |
WTH
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My comments are specific to the CFD depicted. I admit, I no longer know what 'aerodynamic engineer' means. It seems like anyone with a 25-cent computer and thrift-store CFD can now qualify. I submit that he's wrong. His CFD is lacking. Any conclusions based on the latter would suffer. I know something about airfoils. I have the books written by the people who invented and tested them. I've had the privilege to 'fly' some of them. I know something about CFD. People sell all kinds of useless ----. People who buy useless ---- do not constitute scientific validation. I've been wiping my ---- on this stuff since 1974. It's the singular reason why I enrolled in a mechanical engineering program in 1976. My senior project in 1980 involved aerodynamic streamlining specifically. I've hung around the lowest drag cars on Earth since 1989. I've hung around the fastest cars on Earth since 1989. I've hung around the lowest drag human-powered vehicles on Earth since about the same. I spent 4-years around military and research aircraft. I've been a member of the Experimental Aircraft Association International Human Powered Vehicle Association Utah Salt Flats Racing Association I've been in full-scale wind tunnels with my vehicles twice. I built a Cd 0.12 car. I have two Bonneville speed records and one proving ground speed record. Tens of thousands of miles of road testing. All my uncles were pilots. My oldest brother's a pilot. Neighbors and friends are AOA members and pilots. I don't recognize any so-called science to refute, so it would be folly to pursue it. We discussed whale tubercles here, probably a decade ago when it was fresh on the wires. I hoped it had died a natural death. Like I said, you show me any FAA type-certificated aircraft on Earth using tubercles and I'll be all-eyes. PS You might want to brush off your text on Reynolds number. |
The illustration is B.S. lacking.
https://i0.wp.com/blog.gridpro.com/w...6/vortices.png The illustration are angled relative to each other but both depict zero angle of attack. The presuption is that the vortexes generate at an angle of attack. This is not compelling. It also ignores the hair follicle turbcles on the humpback's jaw. Those are even more mysterious. Humpbacks are powerful sound emitters. Poerhaps there is an acoustic function. |
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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. |
I just notice the thread title again. "'Whale Tubercles" cut drag 32% on wings."
That's an extraordinary claim. ~1/3rd less drag? Is that overall or the localized feature? At what angle of attack? What happens to lift? Is it enquiring minds or inquiring minds? |
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