Explain clever people :P

[mep]

Also notice that the third element has a kind of
gurneyflap at the downside.

[DaveKillens]

In the Toyota, the middle element has a complex shape at the rear where it meets the airbox. And if my eyes are correct, there's some kind of Gurney flap there too. The forward element is concave on the upper surface, and on the rear is a small lip. So there's a lot of air management going on.
http://www.f1racing.net/en/photolarge.p ... &catID=110
An element doesn't have to posess a substantial negative angle of attack to have an influence on the rear wing. It would inhibit the airflow from continuing upwards, and the air pressure to the rear of the airbox would be higher than if no element was present.
Mind you, all this stuff does it's magic near the centerline of the car, and would probably have a negligable effect further out near the ends of the wings. But many rear wings possess complex shapes to deal with the air near the centerline, and further out.
My assumption is that if there was no winglets on the airbox, the air on the centerline would have a low peressure, and the middle of the rear wing would not be able to generate as much downforce as the ends. Adding these airbox winglets would create a higher pressure area behind the airbox, and also smooth out the airflow so the rear wing is more effective.

[mep]

--------An element doesn't have to posess a substantial negative
---------angle of attack to have an influence on the rear wing.

Yes but the airbox wings are mounted much higher than the rear wing,
so the vortex may propably not even hit the rear wing.
Have a look an the RedBull wing it's mounted lower
and has a big negativ angle of attack -it's clear that
the air at the Redbull hits the rear wing.



--------It would inhibit the airflow from continuing upwards.

Those wings are very smal, what let me think that they have
only a lokal influence especially at low speed.
Maybe McLaren horns work in such a way and they are also placed lower.
I think depending on the teams have those wings all a special task for itself.
Also have a look at the Renault wing, it seems like it's only task
is to create downforce.

[zac510]

Yes but the airbox wings are mounted much higher than the rear wing,
so the vortex may propably not even hit the rear wing.

Often that is the point of a vortex. You should look into their effect on the upper side of an aircraft wing at high angle of attack to see how their effect might be translated.

[Sknguy-]

Catalunya's an interesting circuit. If you looked at photos of the '06 race most, if not all, cars had slightly more ducting on the right sides of the car than thier left sides. Sorry I don't have pictures. And I know this effects cooling and drag. But I hadn't thought to look at any aero changes that may have hinted at altering the aero's lateral balance. Interesting...

[mep]

zac510 wrote:
Often that is the point of a vortex. You should look into their effect on the upper side of an aircraft wing at high angle of attack to see how their effect might be translated.

Do mean like this?
http://www.mulsannescorner.com/vortexlift.html


First of all the airbox wing has an angel of attack of zero!
Secondly can you explain what kind of effect the
vortex should have on the rear wing when it's flying
over it?
I think it will more have negative effect as it produces
a low pressure area over the rear wing and therefore reduces
downforce.

[zac510]

Do mean like this?
http://www.mulsannescorner.com/vortexlift.html

Yep!

Secondly can you explain what kind of effect the
vortex should have on the rear wing when it's flying
over it?

I've seen no evidence to suggest that a vortex even occurs. I've only seen speculation.

[mep]

zac510 wrote:
I've seen no evidence to suggest that a vortex even occurs. I've only seen speculation.

Maybe I get you wrong, but of course a vortex will occur.
If you move a object through a gas like air, you will allways
produce some vortexies.

The question is only how big the vortex is.

I think wings like those will create quite remarkable vorties.
But even if the flow is laminar don't forget the wing tip vortex.

[zac510]

The question is only how big the vortex is.

Yes, maybe that is just what we are arguing about I'm all outta knowledge so hopefully kilcoo or someone can put us straight!

[kilcoo316]

What vortex where?

On the horizontal mid-wings?


Its negligible, unless there is a pressure differential, there is no induced vortex, there will be two tiny ones from the corners/edges - but these aren't worth talking about.


I reckon the horizontal mid-wings are there to deal with the airflow ejected from the airbox under heavy braking, airbox design concentrates on keeping this flow attached to reduce drag, I expect the mid wing concentrates on ensuring its roughly parallel to the ground plane for optimal rear wing performance.

[tf1]

Unfortunately I can't talk about details about the wing designs, but to answer the general question first posed...

swept wings were developed as a way to reduce the speed of the airflow over the wing as the wing "sees" it so to speak. By angling the wing into the airflow, the airflow perpendicular to the leading edge is going slower than the actual horizontal airspeed of the wing. If it was only to reduce the effects at mach 1+, you certainly wouldn't see it on airplanes like the 747 that don't even see mach 0.9.

There's no reason to sweep the wings on an F1 car due to the speeds involved. It'd be like sweeping the wings on a cessna 152.

[joselu43]

I disagree, the mach number on the upper surface of a 747 wing (at cruise) is definetly sonic. That is why it has a sweep. The same is true of all high subsonic aircraft. I agree with the rest though.

Jl

[joselu43]

Sorry, just read the whole thing and now I think I understand what the idea is. Triangular elements in subsonic flow are generally used to generate a leading edge vortex. The purpose, depends on the application, though generally it is to "energize" the flow. In a delta wing, like the Concord or SR-71, it allows the wing to fly at much higher angles of attack without stalling, on the upper surface on a F-4 Phantom, it delays boundary layer separation. There is great example of that in the Mulsannecorner link above. Using the term "lift" in conection with the vortex generator is dangerous because it implies "up", while the direction of the forces generated depends on the orientation of the element AND the local direction of the aitflow.

Jl

[Ciro Pabón]

Just a question: does not the speed of air close to the body vary according to Bernoulli's principle?

Then there is the law of areas, if I remember well. This means that it depends on the local conditions of the flow to dictate if a shape is useful or not. The effects of wave drag are felt well below the speed of sound, as low as 0.7 mach.

The first aircraft to use tapered wings flew at 500-600 mph. I wonder if this range of speed is attained by the flow close to the body of an F1 car, or maybe when the flow is constricted, like in the space between the elements of a wing.

For example, here it is a Tu-95 Bear as shown in Wikipedia, allegedly the fastest propeller aircraft in the world, initially rated at 620 kph (400 mph), nowadays rated at 900 kph, but with tapered wings from its beginning.

[kilcoo316]

At 400 mph, if your aerofoil sections have a large enough thickness/chord ratio you will experience transonic flow [local supersonic bubbles].

By sweeping the wing, you raise the real vehicle airspeed when transonic flow first occurs.