Exhaust Blown Floor - Forward Exhaust Exit

[MIKEY_!]

If we go off the concept that it creates a vortex to seal the floor then perhaps the rear floor is sealing well enough at low rear ride heights so it is better to seal the step plane.

[shelly]

But we know that ebd, which is about side vortex sealing, works better with high rear ride heights so maybe this is not the point

[PlatinumZealot]

The FEE is going to be weaker at high rear ride heights because the side sealing vortex it creates is interrupted by the rear wheels.

[MIKEY_!]

The rear wheels are still there at low ride heights and if the floor blocks them somehow then it don't need sealing.

[shelly]

I agree with MIKEY.
I think one possible rason is related to vortex stretching - squeezing and adverse pressure gradinet influence on this phenomenon.
Lower rrh means smalle pressure gradient and longer path for the vortex.
Te vortex I am reffering to gose under the floor, it is not on the sied edge for sealing

[godlameroso]

A vortex can both seal the air within a specified volume, and it can help keep flow laminar across a surface. Maybe the FFE can create more downforce than all the other cars, but it's also the most sensitive to throttle position, also if there are walls close to the vortex it would most certainly reduce it's efficiency. Coincidental then that the R31 has done poorly in circuits that require heavy throttle modulation as well as circuits that have lots of armco barriers. However it does reasonably well in circuits that are wide open(or circuits that don't have walls on corner exits) with lots of constant throttle turns.

[marekk]

"We also know that the forward exhaust, by contrast, performs more strongly once the rear ride height starts to compress"

Discuss

Maybe he meant it relative to EBD, i.e.FEE produces more or less constant numbers of DF at any speed, and EBD allows for more rake (more volume and higher expansion ratio for diffusor, higher AoA for the whole car)and more DF at low speeds, but this advantage vanishes as the cars get squeezed to more horizontal position.
At some speed there is a break point - you get more DF from FEE then EBD.
Would be interesting to compare some apex speeds for both types of corners this season.

[PlatinumZealot]

The rear wheels are still there at low ride heights and if the floor blocks them somehow then it don't need sealing.

You know what I mean. Of course the rear wheels are always there. Unless you are michael schumacher in Spa.

At low ride heights you need less side sealing so the rear wheels blocking the air skirt is not as critical at low ride heights. I know you know that is what I meant.

[MIKEY_!]

You need more side sealing at high ride heights and there is more gain for the FEE at these heights (over low ones) but the RBR solution is even better at the higher heights cause the floor acts like a lever and there is much more expansion in the diffuser than in the step plane.

[hardingfv32]

What is the limiting the size of the diffuser exhaust volume?

Why can't you have the same size diffuser exhaust volume as RB without RB's rake?

Brian

[raymondu999]

Would that not be the regulations?

[N12ck]

Hi, the diffuser can be 1000mm wide by 100mm high,

[raymondu999]

I'm slightly confused here. harding, do you mean diffuser exit, or diffuser exhaust?

[hardingfv32]

So, the max dimensions of the diffuser are fixed by the rules.

If then you increase the size of the diffuser exit opening (diffuser exhaust?) by raising the car (rake), would you not also increase the size of the diffuser inlet at the end of the floor?

Does the diffuser create more low pressure if both ends are raised?

Brian

[Sonic59]

So, the max dimensions of the diffuser are fixed by the rules.

If then you increase the size of the diffuser exit opening (diffuser exhaust?) by raising the car (rake), would you not also increase the size of the diffuser inlet at the end of the floor?

Does the diffuser create more low pressure if both ends are raised?

Brian

yes. no.=)