Using front-wing flutter to stall the floor?

[timbo]

So, we know that today the cars rely on a complex vortex structures a lot to generate downforce. Some of the vortexes are generated by front wing.
In light of the new Ferrari wing flexing a lot, could that work to stall the floor due to the vortex structure being disturbed?

[ESPImperium]

I supose it could, better people than me will be able to say yay or no.

But if it does, and if there is a safety aspect i can see the FIA increasing/raising the front wing up a small ammount, maybes by 50mm at minimum, but i think they will increase it by at least 100mm in 2014 with the reduced width of the wing going from 1.8m to 1.6m that is already taking place.

Personally i hate theese front wings and wish they had kept the 2008 front wings, but outlawed those absurd bridge wings, but thats just my opinion.

[shelly]

Using front wing flutter to stall the floor? I think it is not an option.

[ringo]

it cant.
and i don't think stalling the floor is something any team would want to do.

doing that is actually a drag increase.

[shelly]

Wow! Ringo, we agree on something!

But I beg to differ about floor stalling in itself...

[timbo]

and i don't think stalling the floor is something any team would want to do.

doing that is actually a drag increase.

If it puts a "trim" on DF-vs-speed graph you can have more agressive curve without floor scraping ground to much at top speed. This is along the lines of scarbs front-wing f-duct idea.
So, basically any way to limit DF at top-speed can be use to gain DF at lower speeds.

[Sonic59]

timbo, u dont need to limit DF at high speed. U need to limit drag. DF is useful - it helps braking (drag aslo do it, but u can always increase drag by increasing DF).

[timbo]

timbo, u dont need to limit DF at high speed. U need to limit drag. DF is useful - it helps braking (drag aslo do it, but u can always increase drag by increasing DF).

Well, you didn't grasp my reasoning. Say you have a track with a single long straight and a bunch of important 4-5 gear corners -- the problem is that with agressively raked car you may get too much DF on the long straight, that would cause too much scraping. Set the car higher and you don't get enough front wing DF for the corners.
Limiting the floor DF at the top speed you allows you to run the car lower at the medium speeds.

[ringo]

When the floor stalls, the air flow under neath it stops.
The front wing doesn't really have enough of an effect on the floor to prevent all air from going under neath, especailly the T floors of nowadays cars.

Stalling the floor can cause more drag as well. If air was not flowing out the back of the diffuser, it will leave a big hole behind the car thus increasing form drag.
There will be some loss of performance with the rear wing as well.

Also if it is possible for the front wing to attempt to stall the floor, it itself would need to produce a lot of drag, as it has to deflect all that air somehwere else, no air can leak under the wing, between the pylons, under the regulated airfoil section in the middle, or between the wheel and body. This would be difficult.

[Sonic59]

timbo, u dont need to limit DF at high speed. U need to limit drag. DF is useful - it helps braking (drag aslo do it, but u can always increase drag by increasing DF).

Well, you didn't grasp my reasoning. Say you have a track with a single long straight and a bunch of important 4-5 gear corners -- the problem is that with agressively raked car you may get too much DF on the long straight, that would cause too much scraping. Set the car higher and you don't get enough front wing DF for the corners.
Limiting the floor DF at the top speed you allows you to run the car lower at the medium speeds.

Ok. Got it. Good idea. Now the question is how to limit DF.

[timbo]

Also if it is possible for the front wing to attempt to stall the floor, it itself would need to produce a lot of drag, as it has to deflect all that air somehwere else, no air can leak under the wing, between the pylons, under the regulated airfoil section in the middle, or between the wheel and body. This would be difficult.

That's why I wrote about vortexes. Remember pictures from last year's Belgium GP? Teams DO use complex vortex structure. Now, I know that on fighter jets vortexes are used to energize airflow and clever manipilation of where vortexes are shed and where are they going allow Su-27, Rafale, Raptor etc to reach AoA's way beyond where ordinary airfoil would stall.
So, imagine that you have front wing that sends a vortex downstream which arrives at a particular region on the floor, and that enhances the flow under the flow. Now, what happens when the wing flutters -- it would appear to send the vortex rather randomly, and I imagine that could even break up the vortex.
Now, without that vortex the floor would be less effective. Maybe it won't stall, but if it becomes somehow less effective (maybe air would leak to the sides) it would limit the DF.
Surely it would be a major PITA to tune and add a great deal of aero sensitivity.

[hardingfv32]

1) Why do we need vortex activity at the front portion of the floor? Why would there be flow attachment issues in this area?

2) This could be a system almost impossible to tune. Seems like any number of factors would cause issues with when the flutter was to be activated. Say track surface conditions/ smoothness, minor tire vibration, or following/passing another car.

Brian

[timbo]

1) Why do we need vortex activity at the front portion of the floor? Why would there be flow attachment issues in this area?

Well, maybe interactions with the front tyres, or using vortexes as skirts to prevent air from around the floor to get sucked into the low-pressure area?

2) This could be a system almost impossible to tune. Seems like any number of factors would cause issues with when the flutter was to be activated. Say track surface conditions/ smoothness, minor tire vibration, or following/passing another car.

Brian

Come to think of it -- rumors of RBR being extremely unstable in the wake, or Macca losing front DF miraculously.
But yeah, a PITA to tune.

[shelly]

to harding questions:

1)when a vortex get squeezed under the floor, the low pressure of the vortex acts against the floor surface, producing downforce.
The stall of the diffuser does not happen at the leading edge of the floor/sidepod, but at the kink line (rear wheel axis)

2) I agree - using flutter from the wing is not practical.

[timbo]

to harding questions:

1)when a vortex get squeezed under the floor, the low pressure of the vortex acts against the floor surface, producing downforce.
The stall of the diffuser does not happen at the leading edge of the floor/sidepod, but at the kink line (rear wheel axis)

Vortex doesn't get under the floor => Less low under the floor => Stall downstream.