Using wing-end vortices to aid overtaking

[beelsebob]

There's an interesting article out and about today about why birds fly in a V formation. The long and short of it is that it's been found that the bird following positions it's wing tip so that the vortex coming off the wing tip in front creates high pressure under it's wing, and destroys the vortex coming off it's wing tip, making the wing operate more efficiently.

This got me wondering... Do drivers position their car to take advantage of this when attempting to follow another driver through a corner? Obviously they're going to be in dirty air by following, but can they take advantage of this dirty air that's working with their car? Has anyone got any nice CFD software that can simulate downforce levels of two cars arranged in a V formation through a corner?

http://news.sciencemag.org/biology/2014 ... -formation

[n_anirudh]

There are two aspects here: One is the flapping wing and the second the proximity to the road. Slipstreaming, yes is benificial as the drag is considerably reduced, but a V formation would cause more drag for cars in a straight line. (Un)

Also, you have the rotating eheels, which in itself is a challenge to model accurately. I did recall seeing a Sauber CFD video of two cars slipstreaming.

Thats my 2c

[beelsebob]

There are two aspects here: One is the flapping wing and the second the proximity to the road. Slipstreaming, yes is benificial as the drag is considerably reduced, but a V formation would cause more drag for cars in a straight line. (Un)

Also, you have the rotating eheels, which in itself is a challenge to model accurately. I did recall seeing a Sauber CFD video of two cars slipstreaming.

Thats my 2c

Right, clearly on the straight slip streaming is beneficial. But in order to get in a slip stream you need to get sufficiently close to the car in front. What I'm wondering is if it's worth taking a wide line through the corner before the straight in order to maintain position in a V formation, and gain front wing downforce from the car in front's rear wing vortex.

[hollus]

... it's been found that the bird following positions it's wing tip so that the vortex coming off the wing tip in front creates high pressure under it's wing, and destroys the vortex coming off it's wing tip...

...the birds positioned themselves to fly just behind and to the side of the bird in front, timing their wing beats to catch the uplifting eddies...

Quite a difference there. The talk in the paper is of intercepting air that is moving upwards (which also happens to be a vortex). They also mention how a fixed wing model doesn't work. That said, I haven't seen the actual article, just the one page, normal language excerpt.

But if you want to use this by catching the vortex of the car in front, those contain low pressure, not high, so you would need them under the car. How are you going to move something that high under your front wing? Then, anyways, it would do more harm than good, the rotating flow affecting the laminar flow under the wing.

[DaveW]

....This got me wondering... Do drivers position their car to take advantage of this when attempting to follow another driver through a corner? Obviously they're going to be in dirty air by following, but can they take advantage of this dirty air that's working with their car? Has anyone got any nice CFD software that can simulate downforce levels of two cars arranged in a V formation through a corner?

I haven't read the article, but I suspect that any glider pilot will tell you it doesn't work like that.... (Simplistically, updraught gains height, constant height (as in formation flying) requires a lower angle of attack, and hence less lift induced drag).

[Tommy Cookers]

the NASA had a project 'Autonomous Formation Flight' on this sort of thing in 2002
to gain range/endurance by aircraft flying (automatically) in unusual close formation
then there was/is ? a DARPA project, claiming 10-12% range benefit (with large aircraft) to the follower up to 1 mile behind

http://www.theregister.co.uk/2009/05/19 ... tion_ploy/

earlier aircraft studies showed major benefits from such coupled/overlap flight
and some problem regions were identified the hard way

[idfx]

vortices created by insects
[youtube]http://www.youtube.com/watch?v=r3fFL8ZJkKA[/youtube]
rw vortex induced drag

[idfx]

Von Karman vortex street
[youtube]http://www.youtube.com/watch?v=IDeGDFZSYo8[/youtube]
[youtube]http://www.youtube.com/watch?v=h3xybBxFns4[/youtube]
[youtube]http://www.youtube.com/watch?v=Gq-sUhP3kDI[/youtube]
[youtube]http://www.youtube.com/watch?v=GlTcRhh3gYc[/youtube]
http://en.wikipedia.org/wiki/K%C3%A1rm% ... tex_street

If the car's mobile wing as the pagani, and an electronic to make a move with the waves, the motion of vortices combined with the wing reducing drag and gaining speed.

[hardingfv32]

In the video above of a rear wing, is the vortex being formed coming from the slotted end plate? If so, how does this help rear wing performance?

Is this vortex rotating in the opposite direction of the vortex off the main wing elements?

Brian

[DaveW]

Is this vortex rotating in the opposite direction of the vortex off the main wing elements?

This might help....(wings on aircraft are designed to lift, but not on a race car).

[idfx]

Vórtices RedBull
[youtube]http://www.youtube.com/watch?v=nVPEvXn-q8U[/youtube]
Vórtices Ferrari
[youtube]http://www.youtube.com/watch?v=6vZQXQ1pqOE[/youtube]
[youtube]http://www.youtube.com/watch?v=dii29rhHuNk[/youtube]

[idfx]

Great articles here in the forum:
Reducing the drag of a two element wing through stall
http://www.f1technical.net/forum/viewto ... start=1020

[idfx]

Is this vortex rotating in the opposite direction of the vortex off the main wing elements?

This might help....(wings on aircraft are designed to lift, but not on a race car).

Nice
[youtube]http://www.youtube.com/watch?v=ViKYFsN3p24[/youtube]
Nasa
[youtube]http://www.youtube.com/watch?v=uy0hgG2pkUs[/youtube]

[SectorOne]

idfx, all i can say i wow....those vortices were ridiculously big.