The air wing....

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syguy
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Joined: 22 Feb 2007, 04:06
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Air Blowing

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With respect to Ciro's torpedo, air blowing is a useful aerodynamic effect.

Air blowing, also called a boundary layer control system or a blown flap, is a well known means to re-energize a slowing boundary layer towards the rear of an airfoil. The extra energy prevents flow separation allowing a higher angle of attack and therefore extra lift compared to the un-blown trailing edge.

Also increasing the air speed over the entire airfoil by blowing will increase the lift and drag - ever wondered why the engine exhaust on an F1 car is directed at the rear wing? This technique is exploited by wing in ground-effect vehicles such as the Caspian Sea Monster, whereby the front jet engines direct their exhaust jet towards the main wing providing lift independent of forward speed.
Symscape, Computer-Aided Engineering for all

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checkered
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Joined: 02 Mar 2007, 14:32

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@Ciro; biomimicry is certainly

one of the most efficient ways of making improvements. Nothing like millions of years of evolution to lead the way ... there are parallels and connections in this World we can hardly even dream about, I'm sure. The good thing about this is that there's no shortage of things to find out and invent.

About shark physiology, their bodily inductiviness and biological electroreceptors, read this article on Elasmoworld (link). Fancy stuff, all in all. A documentary I saw years ago, if I remember this correctly, claimed that certain sharks can perceive the firing iv the electrical conduction system of their prey's heart miles away. Here's a general lecture on electrosensitivity in animals (link). Clearly we've got a long way to go before we can artificially create such intricate multipurpose systems.

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Picture from Elasmoworld.

On multiple wingtips, there's a Swiss company that has been around for a long time and done a lot of research on the issue. It's called Winggrid (link) and their efforts are well documented on their website.

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Picture from Winggrid.

Another (less biomimic perhaps) wing idea I've been following is FanWing (link). Seems interesting enough, and there's also a related idea (currently being promoted in Korea) called Cycloidal Propulsion (link).

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Picture from FanWing.

@Ogami, yeah, I guess the brain is the main challenge ... I remember reading that if computers' capacity keeps increasing at current rate, we'll be able to solve the air flow around a wing (a non morphing wing, I suppose?) with no compromises or simplifications by 2080. Of course control is a different issue, and that would mean integrating senses to the process. With fuzzy logic, self organizing programs and a change in terminology, perhaps practical aeroelasticity isn't that far off anyway.

Most flapping wing research I've seen recently has to do with MAVs. It's pretty hard to imagine a F1 car fluttering about ... I guess most fans could find that a bit hard to swallow in the near future anyway.

:lol:

Ogami musashi
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Joined: 13 Jun 2007, 22:57

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CP:

The sharks use the riblet effect, that is their skin provides for riblets (the ones you showed) that modify locally the velocity and pressure of the boundary layer where she would transition to turbulent flow witch would create more skin friction drag.

The principle relies on the pressure gradient, I.E the rate of change of pressure along a surface. If the pressure gradient is too high (if the needed pressure required is too far away from the current one) flows will transition to turbulent and start having pressure varying with time and space.


This technique creates more profile drag (drag due to the cross sectional area) but overall will decrease the total drag.

The skark riblets are far more complicated than the riblets used in coatings (that anyway are inspired from sharks...) and i don't know the precise velocity profiles on them, i'll search tough , that's interesting.

But retain the overall goal is to maintain laminar flow, laminar flows are flows than offer less friction drag (less friction with the surface).

The important point here, ciro, is that this technique is primary a technique for reducing the drag that affect the straight line speeds (or max speed in absolute form, but in racing , straights are where we get the max speeds).

As noted by someone i think in the 2011 topic, if you look for downforce, you don't really need to care about that BUT as in 2011 the goal will be drag reduction:why not?!

One thing tough: profile drag increases with the square of speed, so while having laminar flow is always beneficial, if you're using riblet, at speeds that are far from the one used by sharks maybe the profile drag payoff will be too much for the friction drag gain.

That's one thing to look at for plasmas too, if the diodes offer to much profile drag maybe it won't be worth, but on that one i'm sure we will find something.


Actually i'd bet more on morphing. Being able to adapt a wing to the context (speed, yaw or pitch angle) in a complex way (chord, thickness , sweep and lateral camber) would already be a revolution and for sure a big step in performance.


For skval, i'm not too much into it, i'm not quite sure this is how syguy said (despite the fact he's completely correct on the principle evocates), i remember a discussion with a friend that works in MHD the goal was more to lower the profile drag by decreasing the total pressure on the skval, but i may be wrong.
I'll ask and tell you then.

Ogami musashi
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Joined: 13 Jun 2007, 22:57

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checkered:
I think, at least it is the problem with IA at the moment, the limitation is the structure of brains.
i don't know quite much for birds, but for cats and humans, the brain has a fractal structure (past, present and future-i.e our anticipations- are all worked at the same time, in every way, at infinity).
For a computer to do that it is very hard and even not really possible quite a the moment (i'm not a expert on that, i don't know precisely why, i think it has something to do with hierarchy of processing).

The perception is also another problem and in fact it mixes with the structure so definitely there's time before we could even understand the real thing, so to them mimic..


Lol flapping wings would certainly look goof on a f1.
But as you said, perception and control IHMO will be a major part of the 2011 technology, there's already a lot of sensors on an F1 car, i think we could definitely see something interesting...if the FIA don't come and say "hey! your sensor will sense that and next do that! no other way allowed!"..;

I think it will take alot of time before we can mimic the FIA...too complex structure, defies all humans logics(and probably other mammals too).

Ogami musashi
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Joined: 13 Jun 2007, 22:57

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On the shkval, I checked and that was what i thought, they use the supercavitation effect, witch has to final goal to make to projectile flying into a bubble of air thus having far less total pressure than with water.

When the projectile reaches a certain speed, the water is thrown away and a cavity forms, when the cavity forms vapor occurs,then air is sent into the cavity to decrease even more the total pressure reducing the profile drag.


I think it could be of a use for very high speed vehicules in the air , but for F1 i don't think it is necessary.

modbaraban
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Joined: 05 Apr 2007, 17:44
Location: Kyiv, Ukraine

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checkered wrote:I remember reading that if computers' capacity keeps increasing at current rate, we'll be able to solve the air flow around a wing (a non morphing wing, I suppose?) with no compromises or simplifications by 2080.
If things keep going this way i expect Bernie Ecclestone to move Formula1 from real tracks to PC simulation for even more cost cutting and safety by 2060 :lol: Then in 2065 Bernie would force Max to retire. :lol:
Ogami musashi wrote:I think it will take alot of time before we can mimic the FIA...too complex structure, defies all humans logics(and probably other mammals too).
:lol:

PS: thanks guys a great read!
Last edited by modbaraban on 25 Nov 2008, 02:15, edited 1 time in total.

DaveKillens
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The shark skin is also shaped in this manner to discourage any attachment of barnacles or parasites.

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Spencifer_Murphy
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Joined: 11 Apr 2004, 23:29
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As a side thought brought about by the shark-skin theory:

Swimmer's uses this sharks-skin effect of their suits when competing at a high-level. I was wondering if the paint on an F1 car could be textureised to produce this shark-skin effect, in order to reduce drag caused by skin friction (even if this idea was used only on certain parts).

If this could be done would it actually have any real benifit? Are there any deficeits? and would this textured paint increase weight too much for the advantage to actually create a net gain?

any thoughts?
Silence is golden when you don't know a good answer.

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Ciro Pabón
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Joined: 11 May 2005, 00:31

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Well, sure. Besides the diodes that could "stick" the layer closer to the body by electricity, I believe adaptive aerodynamics is going to be in our future. There are many ways to acomplish that, from the systems used in coherent light telescopes (you know, the ones that sense the incoming light, calculate the deviations by aberrations and air fluctuations and respond to them) to materials with memory, that change their shape with temperature (shape memory alloys or Nitinol). These links are not exactly what you suggest, but it's easy to imagine how you could use these materials to achive a "smart shark skin".

Midé page on nitinol

CRG page on adaptive aerodynamics

Actually (another wild idea) you could make them change shape automatically, with the temperature increase caused by air friction. Of course, that's pure science fiction, I think. :)
Ciro

Ogami musashi
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Joined: 13 Jun 2007, 22:57

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CP, Morphing technique (with memory alloys) is definitely a big way to go.

You can shape at a high frequency so you can adapt the wing....

BUT the problem is not here, it is actually in the actuators, the more precise you want to be the more actuators you need to shape the material and unfortunately actuators weight and have some dimensions.

The other problem faced actually as far as planes are concerned is sensors, and for big morphing the translations.
They have to be safe (no asymmetric flows) and fast (few and linear degradations).

I would really love to see that in 2011 on formula one that would be a major change both in design and performance (we could get rid of wings by integrating bodywork downforce generators) but that's complex..Well let's see!

Murphy: as far as drag is concerned i explained to benefits and drawbacks of shark skin, as far as weight is concerned, i think a film would be better.

Giblet
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Joined: 19 Mar 2007, 01:47
Location: Canada

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Humpback whales have bumps onthe leading surface of their fins for a reason. It smooths the flow of water around the wing creating less turbulent air, sufficiently increasing stall angles.

Also, are the slots on rear wing endplates there to do the same thing as multiple wingtips?

Ogami musashi
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Joined: 13 Jun 2007, 22:57

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The endplates themselves extend the chord of the wing thus reducing the vortices so the wings on the end plates should do the same, but some of them are surely here as vortex generators for the aft part of bodywork.

The end plates also split the air so that less density is found on the wheels to reduce drag.

Giblet
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I've wondered for a while, if the left top portion of the wing pointed air towrds the high center, and the right lower portion of the wing directed it to the low center, wouldnt a giant vortex be created behind the car?

It would be an assymetrical design.

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Ciro Pabón
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Ogami Mushashi and syguy explanations and checkered links are great. Giblet brings forward something I've been thinking today.

So, I have just two more questions, if you’re so kind.

a. An “air wing” should be able to do some force on the surrounding air. This force would move the “air wing” in the opposite direction, maybe disrupting it. That's what could be, at the bottom, behind Tomba, saribro and zac's objections.

The only stable vortex I have seen in this world is the Great Red Spot, which is an aerodynamic enigma, or so I’ve heard.

Is there any “modern” explanation for the Great Red Spot? It seems to comply with the conditions of the question: it could be a “wing of wind”. Or, at least, it seems to a novice that something is counteracting the thermal and coriolis forces there: the Red Spot has been circumscribed to the southern equatorial belt for more than 150 years now (maybe 300).

So, here we have a possible aerodynamic solution. Theories you can read are: the shear at the edges of the belt keep the storm in place, OR there is a fountain of heat (like in hurricanes or typhoons) below it. Thus, maybe there are two possible solutions, first a couple of shear currents at the edges of the “air wing”, and second, a fountain of heat on the body of the car. None sounds very promising, I concede gladly…

A possible answer to fastback33 question. Which NACA profile is this? :)
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There is another kind of waves I know that are “stable”: solitons.

The idea is this: the speed of a wave is proportional to its frequency and wavelength. On a normal wave there are many frequencies superimposed. They have different speeds, which leads to the dispersion or flattening of the wave. In a soliton, there is an interchange of energy between different frequencies, with the end result that the differences in speed are cancelled and the wave sustains itself.

A soliton in a channel (the larger wave to the right)
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Of course, I think it seems as difficult to achieve solitons (if that's possible at all) on a flow of air as it sounds... :)

b. Why there are no elliptical wings in F1? I imagine that the advantage they give you are less than their defects, as Ogami Mushashi comments on endplates seems to imply somehow, but stay with me for a minute:

The lift of a wing is more or less proportional to its chord. In an elliptical wing, the chord diminishes the further you are from the body. At the wingtips, the chord is zero, and thus, the lift is essentially zero. This is no good for F1 designers: you wish to achieve maximum lift, so, why "throw lift away"?

Spitfire’s elliptical wing: at the tips there is no lift
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Now, the air flowing under the wing has a tendency to move upwards at the lateral and trailing edges of the wing. I read that is this "upwards push" what causes the vortices at wingtips.

This means that at the wingtips of an elliptical wing this tendency is reduced, because there is no lift. Apparently, this made the Spitfire an “smooth” to follow airplane (and a more predictable one while turning, which allowed you to try to tighten the turn and receive a "warning" from the controls, before stalling the wing).

It occurred to me that a source of inspiration could be migrating birds, which fly in flocks. After all, they have evolved to fly close to each other. I say yes: to an amateur they seem to have this kind of wings, or at least a reasonable approximation. Have any person in the F1 world tried to get some inspiration from them? Maybe this design has some merit: perhaps it gives you less "dirty air" AND reduces downforce, or so I think it's probable. I shouldn't say it, but it seems a really good idea.

A flying aerodynamics teacher?
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On the other hand, buzzards have more “blunt” or square wings. They fly alone, like Massa wishes to, when qualifying behind Alonso… :)

Wing enhanced for lift, that leads to solitary flights?
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Another example is a school of fishes. They seem to have evolved to swim very close to each other. They seem, again, for an amateur, to have a tail thicker at the external edges and thinner at the center, not far from the “split wing” proposed (and apparently rejected) to enhance overtaking.

Swim, swim. What do we do? We swim...
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Well, I don't know if any of this is workable. Any suggestions? Sorry for the long post.
Last edited by Ciro Pabón on 08 Sep 2007, 04:08, edited 1 time in total.
Ciro

Carlos
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The March 711 F1 used an elliptical front wing mounted on a very short strut ,over a rounded nose cone. One of my favourite cars.

EDIT - Because of it's "odd" front wing, it was called the "tea tray" March. There were many references to the Spitfire; some thought it was just a nostalgic nod to the airplane. It did pretty well compared to cars with more conventional aero finishing 2nd in the drivers championship in 1971 driven by Ronnie Peterson.