Is Aerodynamic Design influenced by the Animal Kingdom?

[Vyssion]

This topic was brought up in the 2018 Aerodynamic Technical Regulations sticky thread which picked up some steam. Rather than fill that thread with all the bird feather talk, I figured moving it out to here for people to carry it on would be better. For the good of all Toucans

Heres the link to the start of the posts for those interested:
viewtopic.php?f=6&t=26955&start=20

Okay... lots of comments to read here - gonna add my two cents worth to the argu.... errr I mean discussion!!

I dug out one of the papers in my archive which relates to this type of thing. It was a paper called "Bionic Research on Bird Feather for Drag Reduction" where they performed a micro-scan of toucan feathers and then manufactured 3x surfaces (with 1x smooth surface) to kind of "replicate" the micro-structures.

Here is the scan below for you to see what they were based off:


What they decided to do was essentially push a sheet of metal through two rollers with one of them having tiny little riblets which would dig into the sheet metal to form little channels similar to what they scanned. This was then placed in a wind tunnel and tested against a smooth plate. Here is what they found:


Between a Mach Number of 0.4 and 0.9, there was indeed a noticeable drag reduction efficiency gain of the ribletted plates vs. the smooth plate with the most noticeable effect being dependent on the surface geometry vs. speed. You can see that at higher Mach Numbers, the effect actually ends up having a negative effect vs. a smooth plate. Similarly, you can see that as the Mach Number drops away from 0.8 to 0.4, the gains of some of the surfaces are less substantial.

This is important as far as this discussion because F1 cars at Baku (372 km/hr top speed as I recall seeing) still only just hit a Mach Number of ~0.3 (plus or minus some amount due to temperature/humidity, altitude, etc.) and so I feel kinda confident that, at least with a toucan feather microstructure, there wouldn't really be any significant gains to be had by implimenting this type of surface. It is made worse by the fact that the flow structures over the cars as they drive in a straight line are not always perfectly aligned with the direction of travel - let alone when they are cornering!! This paper doesn't go into yaw effects with aerodyanmics, but I feel okay saying that your benefit would probably drop off at least by some amount.

My guess as to what is happening is that the little vortices which are induced within these channels have a "reduction" effect on the shear stress within the airflow. They probably induce a tiny increase in pressure though, simply due to there being more churning about on a surface with more surface area etc. Both of these would reduce the skin friction drag by a fair bit.

TLDR; too complex to impliment in a way which works for all flow conditions/directions which doesn't have some amount of flip-flopping between working and not, and the fact that most gains to be had are outside of the speed ranges of F1 cars. The other thing is that all of this skin friction drag reduction etc etc would pale in comparison to the drag reduction of something like a DRS system..................... oh right!! We already have those

[Just_a_fan]

alternative TL;DR
Low speed stuff doesn't always work as speeds increase.

Detail
Birds generally fly at speeds lower than the cornering speeds of F1 cars (a few exceptions noted, of course). Only one or two birds get anywhere near F1 top speeds and feathers aren't what they change in order to go fast - hint: they pull in those big draggy wing things and make like a rain drop.

Conclusion
Feathers ain't what F1 needs or is working towards.

[godlameroso]

I think you misunderstand the whole point of this exercise, it's not that F1 cars are copying, 1:1 bird feathers, it's that F1 cars are copying features and geometry of birds in certain critical areas. Maybe it's hard to see because a bird is designed mostly for positive lift, an F1 car for negative lift. Furthermore the car has constraints imposed on it and a bird has other constraints imposed on it. However a bird isn't just feathers there's more features on it's body that interact with air in interesting and novel ways. There are drag inducing, drag reduction, passive flow control structures, structures that promote stalling, or reduce flow separation. The tail itself and the way it interacts with the main wings is very similar to an F1 car in principle only inverted. Again not 1:1 but in principle, the beauty of the laws of aerodynamics is they apply everywhere at all macro scales.

Look at the front wings of most cars, the flaps responsible for the y250 look an awful lot like bird wing tips, just inverted.



The Force India is a perfect example, particularly the 3 upper flaps, look an awful lot like your toucan pictures.

[johnny comelately]

I think you misunderstand the whole point of this exercise, it's not that F1 cars are copying, 1:1 bird feathers, it's that F1 cars are copying features and geometry of birds in certain critical areas. Maybe it's hard to see because a bird is designed mostly for positive lift, an F1 car for negative lift. Furthermore the car has constraints imposed on it and a bird has other constraints imposed on it. However a bird isn't just feathers there's more features on it's body that interact with air in interesting and novel ways. There are drag inducing, drag reduction, passive flow control structures, structures that promote stalling, or reduce flow separation. The tail itself and the way it interacts with the main wings is very similar to an F1 car in principle only inverted. Again not 1:1 but in principle, the beauty of the laws of aerodynamics is they apply everywhere at all macro scales.

Look at the front wings of most cars, the flaps responsible for the y250 look an awful lot like bird wing tips, just inverted.

https://imgr4.auto-motor-und-sport.de/F ... 154029.jpg

The Force India is a perfect example, particularly the 3 upper flaps, look an awful lot like your toucan pictures.

https://c1.staticflickr.com/9/8239/8541 ... 1af5_b.jpg

Thats right, though it may not be copying: one worked it out with super duper puters and stuff and the other with a bird brain

[J.A.W.]

Well, who knew 'crinkle cut chips' were so aero-sophisticated?
Or that ol' man Junkers had the corrugated skinning on his aircraft worked out so cleverly, too..

Well sure, when it comes to fluid dynamics, its a needs must - in an efficiency situation, viz Lionfish:

[FightingHellPhish]

Well, who knew 'crinkle cut chips' were so aero-sophisticated?
Or that ol' man Junkers had the corrugated skinning on his aircraft worked out so cleverly, too..

Well sure, when it comes to fluid dynamics, its a needs must - in an efficiency situation, viz Lionfish:

http://3.bp.blogspot.com/-dCL22S4HG-M/T ... fish_1.jpg

Those things are supposed to be good eats >_>

[johnny comelately]

You're a champ Vyssion

[J.A.W.]

Well, who knew 'crinkle cut chips' were so aero-sophisticated?
Or that ol' man Junkers had the corrugated skinning on his aircraft worked out so cleverly, too..

Well sure, when it comes to fluid dynamics, its a needs must - in an efficiency situation, viz Lionfish:

http://3.bp.blogspot.com/-dCL22S4HG-M/T ... fish_1.jpg

Those things are supposed to be good eats >_>

Yeah for sure, a good feed of fresh fish 'n' chips - is a personal fave.

& while the potential for F1 - utilizing 'shark-skin' micro-finishes has been discussed in earler threads,
here from Harvard Uni is a recent appraisal of the shark-scale vortex-effect as applied to aerodynamics..

http://www.seas.harvard.edu/news/2018/0 ... d-turbines

[Tommy Cookers]

the Junkers corrugated skin gave drag an order of magnitude greater than was thought at the time
(as did a lot of other stuff eg 'bracing' wires of biplanes)
Junkers was famously wrong
(the skin was for structural benefits but only the Thorp light aircraft has attempted it since)

because of insufficient Reynolds Number similarity (wind tunnels being aerodynamically smaller than real world)
the extent of Re similarity needed only emerges after decades of poor design due to insufficient similarity

adequate Re similarity takes years, costs billions, and becomes inadequate a few years after it's provided
costly after-build modifications to the F/A 18 E/F and the T45 were needed for this reason


nature's flyers operate at very low Re Nos and are full of design that is specific to very low Re numbers

[NutritionFact]

Hy guys, in this link you can read something about bionic surfaces on planes... The Austrian laboratory or factory? Is quiet close to red bull..

http://www.bionicsurface.com/en/world-c ... d-passion/

[Just_a_fan]

Look at the front wings of most cars, the flaps responsible for the y250 look an awful lot like bird wing tips, just inverted.

The Y250 flaps are trying to make a really strong single vortex. The bird's wing isn't.

I can position the fingers of my hand to mimic the wing tip primaries of a bird. Will my hand do the same as the wing and let me flyyyyyyy? Er, nope.

[godlameroso]

Look at the front wings of most cars, the flaps responsible for the y250 look an awful lot like bird wing tips, just inverted.

The Y250 flaps are trying to make a really strong single vortex. The bird's wing isn't.

I can position the fingers of my hand to mimic the wing tip primaries of a bird. Will my hand do the same as the wing and let me flyyyyyyy? Er, nope.

Good question, are your fingers airfoil shaped? If not I'd say you're at a slight disadvantage.

[PhillipM]

Well, yes actually, the tops are generally much flatter that bottom. It might not be a very good airfoil, but still...

[FightingHellPhish]

Well, who knew 'crinkle cut chips' were so aero-sophisticated?
Or that ol' man Junkers had the corrugated skinning on his aircraft worked out so cleverly, too..

Well sure, when it comes to fluid dynamics, its a needs must - in an efficiency situation, viz Lionfish:

http://3.bp.blogspot.com/-dCL22S4HG-M/T ... fish_1.jpg

Those things are supposed to be good eats >_>

Yeah for sure, a good feed of fresh fish 'n' chips - is a personal fave.

& while the potential for F1 - utilizing 'shark-skin' micro-finishes has been discussed in earler threads,
here from Harvard Uni is a recent appraisal of the shark-scale vortex-effect as applied to aerodynamics..

http://www.seas.harvard.edu/news/2018/0 ... d-turbines

Very neat. Seems like altering size, shape, and number is an obvious thing to me as different areas have different requirements. My question is.. what should the scale of the denticles be or is it even an issue? What sort of turbulence do they produce in their microscopic scale on the Mako vs their larger size on an airplane wing?

Or does the design of the denticles create a vortex that dissipates so quickly that it is a non-issue?

[godlameroso]

Well, yes actually, the tops are generally much flatter that bottom. It might not be a very good airfoil, but still...

Due to kinetic linking you can steer your moving body with your thumbs, this is the principle between Asian arts like Tai Chi and Bagua-zhang, Aikido and Greco-Roman wrestling. Keeping with the current theme kinetic linking is also present in F1 suspensions.