F1technical.net

timbo wrote:

shelly wrote: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.

Here we go again...

Its a pity I know nothing about aerodynamics, but I have always wondered if teams work in the tunnels/CFD with vibrating and/or moving (pitch, heave and yaw) models.

In may view the deisgns, methods and knowledge availiable right now are in such a level that would permit that kind of studies, and Im sure theres much to win there... if thats not what Adrian is already doing

Pitch heave and yaw is the norm in wind tunnel. Aeroelastic effects: I do not think they are tested in windtunnel in aeroelastic similarity, but I do not know for sure

shelly wrote:Aeroelastic effects: I do not think they are tested in windtunnel in aeroelastic similarity, but I do not know for sure

They would probably a great pita to test, although flutter and buffeting are studied on plane models.

shelly wrote:Pitch heave and yaw is the norm in wind tunnel. Aeroelastic effects: I do not think they are tested in windtunnel in aeroelastic similarity, but I do not know for sure

Ferrari appear not to have tested their latest front wing design properly - as used intermittently in India...

I think Ferrari is trying to figure it out, but its not hitting the nail

Why cant they test their wings like the guy on the video?

[youtube]http://www.youtube.com/watch?v=aZQlmxrmjXQ[/youtube]

Here is Ferrari's version..... Now, how much down force might we generate if only we could make the wing tips deflect in phase....

@belatti: if you want to test aeroelastic behaviour in wind tunnel you have to get aeroelastic similarity, i.e. scaling correctly mass and stiffness. If we take into account that by regulation (and for technical issues also) reynolds equlivalence is not achieved in a f1 tunnel, we can think that aeroelastic similarity is very difficult to achieve.

This ovelooking effects such as other cars' wake (see hrt example for massa), inertial effects due to abrupt changes in track elevation, and real parts elastic characteristics.

A possible approach could be coupled structural+cfd simulation.

Still it is interesting that the first deformation mode of the wing was a see saw oscillation.
If one relies on the hypothesis (which is no more than a wild guess) that the key for building a flexi wing compliant with the rules is the fact that aeroload is symmetrical whereas the fia flex test is asymetrical, then this kind of see sawing maybe fits in the picture.

To be fair to Ferrari engineers, Massa's car ran (presumably stably) for 32 laps. It ultimately went unstable only when the DRS was deployed, & (perhaps significantly) after the collision with Hamilton. One might guess that the fuel burn slowly reduced mean front ride height (as the rear moved up), the DRS would, presumably, further reduce front ride height, & (possibly) rear damage might have also had an effect. Finally, lack of wing structural stiffness caused one side of the front wing to stall (randomly), initiating the wing flutter in roll.

In other words, they almost got it right. The fact that they didn't (quite) was an insight into what they are actually attempting to achieve, in my view.

IF we ASSUME the goal is flutter at a certain speed range, what are the parts of this puzzle that make it a performance benefit?

My first question would be what does flutter do to the flow at the rear of the wing? More or less vortice for example?

Brian

@DaveW, the flutter happened in other circumstances too. It was not just the one instance.

Be grateful for more details...

alot of excess energy is being created by the flutter, IMO something is going to fail and break

This probably has already been said but...

I think they are trying to get the wing to stay down. However it's coming too close to the ground.It comes so close that the flow stagnates then stalls and the wing springs back up after losing the suction underneath.

Wise words from Ringo.

This stalling on the FW may be having a stalling effect on the floor, however it would be doing it only for very short spaces of time. I doubt this is effective.

volarchico wrote:@DaveW, the flutter happened in other circumstances too. It was not just the one instance.

I'd be grateful for more details....

Incidentally, Vettal's front wing also fluttered momentarily whilst braking during Q2 at Abu Dhabi.... See here.