Posted on 01/18/2022 8:35:41 AM PST by Scarlett156
Trailing-edge noise is the dominant source of sound from aeronautical and turbine engines like those in airplanes, drones, and wind turbines. Suppressing this noise pollution is a major environmental goal for some urban areas.
In Physics of Fluids, researchers from Xi'an Jiaotong University used the characteristics of owl wings to inform airfoil design and significantly reduce the trailing-edge noise.
"Nocturnal owls produce about 18 decibels less noise than other birds at similar flight speeds due to their unique wing configuration," said author Xiaomin Liu. "Moreover, when the owl catches prey, the shape of the wings is also constantly changing, so the study of the wing edge configuration during owl flight is of great significance."
Trailing-edge noise is generated when airflow passes along the back of an airfoil.
(Excerpt) Read more at phys.org ...
I recognized this as an owl because I actually saw one almost take my pet parrot, Charlie Cockatoo, one day while I was sitting out on the porch. (This was some years ago; I never sit out on the porch anymore because crack addicted freaks who started moving in after I moved here.)
It was so fast I almost didn't know what I was seeing, but Charlie SCREAMED (louder than usual) and I immediately stood up - although I didn't see anything - and something that looked like a bundle of gray rags DID A FLIP IN MIDAIR and sailed back into the pines that are heavy in the yard here. I was like, "Oh, that's an owl." Charlie was out of his cage at the time, walking up and down on the porch rail like he used to do before we stopped going outside - he saw the owl and knew he was in big trouble, even though the bird was a bit smaller than he.
We used to hear them hooting all the time but now that is rare, because - yes, you guessed it - crack addicted criminals who moved into the neighborhood, making life miserable for everyone who just wants to live, work, and paint a crazy picture every once in awhile.
Pretty good design for a series of random mutations!
“Trailing edge asymmetric serrations”
Interesting concept.
Birds have very soft flexible wing surfaces.
Application to aircraft? Not sure.
I think composite structures have different resonances than conventional aluminum and alloy wings.
“Paint A Crazy Picture,”
Ha, that’s Entertainment!
Thanks,
Trailing edges are Fascinating !
“Pretty good design for a series of random mutations!”
Survival of the fittest over eons of mutations.
Sounds more like,a wandering Napa Valley rebob, aka flying monkey- they love parrots
https://crypticchroniclespodcast.com/the-napa-rebobs/
Now replace the landing gear with Claws!
Actually a lot of birds, if you can see their wing surfaces and feel them, they aren’t what you would call “soft” - they are brittle-feeling and stiff, like an airplane wing.
One thing I’ve noted with owls in flight is that they are very quiet and can turn on a dime. Some of them aren’t as “fluttery” as the ones in the woods here - these tend to be of the “screech owl” type. Big owls like barn owls are built more like large raptors and their feathers and wings are stiffer.
Pretty good design for a series of random mutations!
= = =
Yep, and a jillion ‘smart’ human designer brains did not come up with that.
Those giant muscular feet are the best landing gear. The claws, I think, provide some slippage so you don’t just tumble on the ground.
Oh, how fun!
Owls are a composite of unique functioning parts. It’s almost as though they were...created...that way.
Owls are amazing night predators. Super quiet, fantastic hearing and good night vision. Their eyes are actually shaped like lightbulbs with the “bulb” part, the light gathering part, in their skull. That they’re adept hunters of mice, which are small and also have extraordinary hearing, is a testament to their design. One can see why many American Indian tribes consider owls harbingers of death.
Owls go after Jays? Bring more owls.
With fuzzy leading edges to break up sound.
I note that Burrowing Owls and Brandon, have many similarities!
The Sharp-shinned Hawks around here harass them. Pretty cool to watch five of six jays try to avoid getting caught.
I hate them with a passion and shoot them whenever I can with my pellet rifle.
The hate really surfaced several years ago when I saw a Jay trying to get into my chickadee nesting box on the day they were fledging. Thinking all the chicks had left, I ignored it. Several days later when I went out to clean out the box, I found a dead chick that had it's eyes pecked out.
It's been war ever since.
Lol, have been watching “monsters in america” series, and they featured that f,Ying monkey on one of th3 shows. They have some pretty bizarre creatures/myths, like,the pig man of Vermont, bat-squatch (a flying sasquatch lol) etc. The show is a trip
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