## The air wing....

Here are our CFD links and discussions about aerodynamics, suspension, driver safety and tyres. Please stick to F1 on this forum.
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syguy wrote:MMUK you are right in that it appears the shark skin effect is tailored for turbulent boundary layers - same goes for riblets. So your point is valid that in the riblet case it needs a turbulent boundary layer to see a benefit. I'd guess if the flow over a shark could remain laminar it would experience less drag than the riblet case, but the Reynolds number of the flow over the shark is likely too high and hence its use of riblets to counter the higher turbulent boundary layer skin friction.

Ogami, for clarity I wasn't advocated that the shark skin produces laminar flow.

Let me make sure i am understanding this correctly here guys.

So a sharks skin creates a uniform layer of drag around it's actually body which then makes the shark more efficient while swimming through water? Am i totally misunderstanding this or am i on the right track?
fastback33
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Joined: 29 Aug 2007

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One way to view shark skin (or riblets) is as a means to 'lubricate' the passage of the turbulent boundary layer adjacent to the skin. In so doing the frictional drag force (skin friction) adjacent to the skin is reduced.

Skin friction is dependent on the viscosity of the fluid (water in the shark case), the velocity rate of change (gradient) adjacent to the skin and the surface smoothness.

Drag isn't a layer; it is a force that opposes the motion of an object through a fluid. It consists of a profile or pressure drag and skin friction drag. You'll also hear about induced drag typically in relation to wing tip vortices - this is a finer grained breakup of the pressure drag. Parasitic drag is another term that is used to lump all the non-aerofoil based drag (pressure based and skin friction), for things like the suspension on an F1 car.
Symscape, Computer-Aided Engineering for all
syguy
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Joined: 22 Feb 2007
Location: USA

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Hi,
I've just enjoyed reading this whole thread from the beginning. As I read the torpedo section, I briefly wondered how good it would be if a similar effect could be had for an F1 car. That is, the air is pushed aside, and a vacuum is somehow forced all round the car. It would really slip along! Mind you, downforce would then be limited to gravity. And the driver would soon be out of breath (not to mention the engine). And cooling would be reduced to radiation alone.
Slightly more realistically, I wondered why no-one has mentioned ultrasonic manipulation of the nearby air. Electrical manipulation (ionization) has serious weight and energy problems, but sound is easy to generate, and focus, with lightweight equipment.
Imagine temporary "surfaces" (made of standing waves), which can be altered swiftly to change the body shapes. No part of the car moves or flexes, but the passing air certainly discovers an obstacle with a changing skin passing through it.
Tom
Tom Hockley
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Joined: 26 Sep 2007
Location: Melbourne, Australia

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i don't know too much on that , do you have any link or informations?
thanks.
Ogami musashi
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Joined: 13 Jun 2007

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Tom Hockley wrote:Slightly more realistically, I wondered why no-one has mentioned ultrasonic manipulation of the nearby air. Electrical manipulation (ionization) has serious weight and energy problems, but sound is easy to generate, and focus, with lightweight equipment.
Imagine temporary "surfaces" (made of standing waves), which can be altered swiftly to change the body shapes. No part of the car moves or flexes, but the passing air certainly discovers an obstacle with a changing skin passing through it.
Tom

Is there a significant

interaction between those scales of excitation of the medium? Do you have an idea as to the amounts in which an F1 car moving through the air transfers its energy to acoustic/ultrasonic phenomena currently? Thinking about it superficially, it can't be a great percentage, but given the margins of success in this sport it might yet prove to be significant even if there's an application that makes aero .5% more efficient. And thinking way outside the box there would seem to be an off chance of some radical developments.

There's lab equipment that can suspend a small droplet in a standing wave, at the "crosshairs" of axial radiation pressure and radial Bernoulli stress. Replicating an effect anywhere similar to that on the surface of an F1 car is a task indeed. Perhaps it should also be examined whether some kind of an acoustically driven convection or "acoustic streaming" would help manipulating boundary layers and flow separation to gain an advantage. I only looked at it superficially and at least initially it seems a long shot, the examples I found used compressible liquid, not a gaseous substance. The interesting part is, acoustic straming can apparently be generated by rapid heating or cooling of a substance ... and the engine produces heat in abundance.

Since the air that passes the car body is moving at some speed, it's an interesting thought whether the engine's heat transfer could be harnessed to aerodynamical uses far more elegant than what is happening nowadays. And of course, different parts of the engine are already quite literally tuned for performance - so why not the whole car body? Yes, I know, highly speculative to wildly uneducated hyperbole, this. But I do share Ogami's intrigue in this.
checkered
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Joined: 2 Mar 2007

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Sorry Ogami, no links or info really. Just daydreaming.

It just seemed to me that when the discussion moved into plasma considerations, that we were omitting a much easier (and likely more profitable) technology. My only practical experimentation with standing waves has been in antennae design. But it has always seemed to me that we could use similar "tuning" techniques to achieve all sorts of useful effects with sound (and light for that matter).

Along similar lines, I remember reading (many years ago) about an invention to reduce the cab noise for truck drivers through the production of phase-inverted soundmatches to the offending noise. And recently, I read of the awesome, and only slightly related, standing waves that sometimes occur in narrow straits or channels.

I suspect there is huge potential for sonics in motor cars. Two more daydreams; active (ie audio-active) exhaust pipes where the pipes "talk" to the exhaust stream, instead of just reflecting/deflecting it, to assist the tuning; or audio-balancing dampers & suspension components (springs plus gas plus sound projectors). But, I am now drifting very off-topic.

I too would love to know of any studies involving audio manipulation for aerodynamic objectives.

Tom
Tom Hockley
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Joined: 26 Sep 2007
Location: Melbourne, Australia

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A patent Abstract: Ultrasonic Aerodynamic Drag reduction/ Increase Lift:
http://www.freepatentsonline.com/4741498.html
Marine Application: Ultrasonic Forcing on a Turbulent Boundary Layer:
Patent Abstract: on above:
http://www.patentstorm.us/patents/53599 ... ption.html

I have also come across aero research using multiple ultrasonic transducers vibrating a surface coating, similar to the first patent abstract.
Carlos
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Joined: 2 Sep 2006

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All three articles take the approach of INTERFERING WITH the boundary layers themselves. I was thinking more along the lines of MOVING the boundary layers by effective body-shape changing, by the temporary manipulation of the air using sound.

Initially, I imagined the placement of a few transducers at key positions, now I'm thinking of whole surface coatings with material of high piezo-electric capability. With appropriate controls one can imagine the vehicle adding to its forward motion by worm-like skin activity through the air, in addition to achieving best shaping for the aerodynamic need at the moment.

Of course, the weight penalty would seem a massive deterrent. But what if it was paint-thin?

How could it all be controlled? Surely a massive network of cabling would be needed? Not necessarily. Only tiny power needed, microfibre conductors embedded in monocoque.

I'm getting skin-creep imagining the possibilities (sorry, joke!). Vaguely remembering morphing segments of leading edge of wings (used in some old aircraft for in-flight de-icing).

Returning to the articles you showed Carlos, I was just wondering if those techniques could be applied at the many points on an F1 car where vortice reduction was attempted/achieved. Would the ultra-sound solution be more controllable, more effective, less weighty, and less aerodynamic compromise?

Tom
Tom Hockley
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Joined: 26 Sep 2007
Location: Melbourne, Australia

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Well, I'll never forget a guy I studied with in 1976. One day he came with this crazy idea about a sound microscope, long before echography was invented.

Welcome, Tom Hockley: I confess I did not understood my mate back then, either....
Ciro
Ciro Pabón
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Joined: 10 May 2005

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Tom Hockley Welcome onboard the speculative engine, most modestly called the F1Technical Forum.

An archeological dig through the cobweb- optical fiber threads on aero could be more exciting than the next Indiana Jones sequel. Buried is an ancient "scroll" where morphing surfaces and my first mention of ultrasonics impacted discussion with the might of a feather (sigh)

I tip my fedora Tom - Thanks for reintroducing and extending the discussion of ultrasonics. Ogami Musashi commented earlier on this thread that the morphing of a bird replication outstrips out currnet computational hardware capacity. Current ultrasonic transducers don't have the wattage to create a morphing aero-body or air wing. But then, when the Apollo program started there wasn't a booster rocket with the thrust to put that payload into space. The hardware will catch up, immodestly our discussion and thousands of other speculations will push developement.Like the progress in graphics. Sprites to Halo 3

Before comments that ultrasonic transducers of that power would destroy the car, perhaps it could be separated/suspended on an electro-magnetic field, standing wave or using a combination of ultrasonic transducers ( or computer control of transducer frequency ) dampening to protect the chassis.

Champagne bubbles and Ciro's intro of the torpedo bubble generator clothing the body affects the boundry layer and lowers drag, as so many have commented. I fuzzily explain it with ancient porting lore. At one time intakes were polished to a mirror, without blemish; then it was discovered that the slippery walls encouraged the formation of droplets. Smoother is not always better. In aero smoothness makes drag. If we all went shark fishing off of Columbia's Pacific coast...drank a few rounds... before our politically correct catch and release ... we would probably see that the sharks riblets/scales/micro strakes came in several sizes at different locations on the body... we could play 'poke the shark'

One of the great promises of F1T is that we have a sandbox/ beach/ fishing boat rental where we can 'poke the shark' and woodshed. With F1's cycle of R&D then ban the results . This is a great place.

Welcome on deck Tom Hockley. Welcome to the crew.

EDIT - What I mean is the forum allows us technological speculation that the constant changes in F1 rules don't or would probably ban. How else to explain brainstorming about the air wing 4 pages?
Carlos
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Joined: 2 Sep 2006

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About the ionizing thing, you could reduce drag greatly if you use it on the front wing, something like this
I have that Twitter -thingie now!
tomislavp4
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Joined: 16 Jun 2006
Location: Sweden & The Republic of Macedonia

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To ionize a gas you need to have an anode and cathode between which ions flow and complete a circuit. The voltage difference has to be in the KV-MV range.

To have the ions affect the bulk flow around them, you need to strategically locate the anode and cathode to achieve your goal. If you wanted to redirect the bulk airflow around a wheel you would need to place the anode/cathode on the wing, where you have the ionizing grid, and the matching cathode/anode on the outer rim of the tire/wheel.

Ions have to have a reason to flow somewhere - it’s the voltage difference that directs them. You might be able to impart a little force using magnets, but more than likely trying to use them will conflict with the direct ion path resulting in the need for a larger voltage to sustain the ion stream.

The problem with ion flow is the large voltage needed - it’s a major hazard likely to spark and cause fires or worse - electrocution.
Symscape, Computer-Aided Engineering for all
syguy
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Joined: 22 Feb 2007
Location: USA

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Hey guys, sorry if this idea has already been posted, I would search the poic first but tbh I really should be revising for my aerodynamics exam tomorrow.

Anyhow, while revising I thought of this, blown flaps. Would it be possible to have a small pump installed into an F1 wing, this being linked to a series of perforations on the underside of the wing, this could either be positioned at around the centre chord point in order to suck air in, thus sucking the air towards the wing surface helping it stay laminar and attached, insted on detaching at high angles of attack.

Alternatively, the pump could blow air out, with the vents positioned at the leading endge, thus energising the flow by speeding it up in an effort to keep it attached to the wing surface and thus laminar.

I know that the theory works, as I've studied its applications on aircraft wings in my aerodynamics lectures. But I was wondering if there are any reasons why it hasn't been used in F1. I can only imagine rule constraints, or weight problems (or as a result higher Centre of Gravity.)

Any thoughts?

cheers
Silence is golden when you don't know a good answer.
Spencifer_Murphy
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Joined: 11 Apr 2004
Location: London, England, UK

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I think we did touch on blown flaps briefly, but yes they and boundary layers suction are viable alternatives to create more downforce while minimizing drag. If you are interested in blowing applications see: http://www.symscape.com/blog/air-blowing-applications

Can't comment on the legality though - the ultimate F1 'sucker' was the Brabham BT46 fan car by Gordon Murray, that handily beat the Lotus 79 (Chapman's refined ground effects car that went on to win the 78 F1 World Championship for Andretti) on its first and only outing. Though not banned, Eccleston (principal of Brabham at the time) withdrew it from the championship to smooth his ascendance to F1 supremo.
Symscape, Computer-Aided Engineering for all
syguy
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Joined: 22 Feb 2007
Location: USA

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Spencifer_Murphy wrote:... blown flaps. Would it be possible to have a small pump installed into an F1 wing, this being linked to a series of perforations on the underside of the wing, this could either be positioned at around the centre chord point in order to suck air in, thus sucking the air towards the wing surface helping it stay laminar and attached, insted on detaching at high angles of attack.

Alternatively, the pump could blow air out, with the vents positioned at the leading endge, thus energising the flow by speeding it up in an effort to keep it attached to the wing surface and thus laminar.

I know that the theory works, as I've studied its applications on aircraft wings in my aerodynamics lectures. But I was wondering if there are any reasons why it hasn't been used in F1. I can only imagine rule constraints, or weight problems (or as a result higher Centre of Gravity.)

Any thoughts?

Well, as soon as

you have a device imparting mechanical energy into the flow it's really hard to have it fall under the current rules as you say (single engine, no moving aero parts, you name it). Future regulations could accommodate something like this. It's well known that such devices can do wonders, achieving CL 2-3 times better than conventional flaps (though such unidimensional comparisons are somewhat poor). There are "issues" with reliability and complexity. The current F1 usage of "exhaust gas thrust vectoring" is pretty rudimentary in principle, but I guess more sophisticated systems could really easily screw exhaust tuning and such.

I haven't looked into the levels of output required to sufficiently energise boundary layers over particular parts of a F1 body, or whether they're justifiable as additional energy "expenditures". If such technologies were allowed I wouldn't expect F1 to look quite the same as today anyway, so I'd start on quite a general level with this sort of stuff. I can imagine the amounts earmarked as "recoverable" in the short term being enough and interestingly, a resource such as braking energy is available at times of greatest need and propably is also very well dynamically proportioned. How'bout that?! Well, TBH I'm not a big fan of the "push pass to confuse" systems anyway, so of course I'm going to promote anything that springs to mind as a possible replacement technology.

So, OWG, get back together and read some F1T, right? Somewhat unlikely ... but I can also envision a completely passive blown flap system with no mechanical moving parts. Propably a very ineffective one and more easily categorised under another BLC methods, but as long as there have been things in F1 such as wing profiles changing dimensions in relation to internal pressure loading, I guess there are ways around anything ...
checkered
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Joined: 2 Mar 2007

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