AR3-GP wrote: ↑15 Sep 2022, 20:58
I do believe Red Bull have replicated some kind of diffuser stalling system. You say the floor doesn't cause drag, but it does. The floor has turning vanes at the front. Those introduce flow losses. The floor and diffuser have aggressive volume expansions which introduce losses. The skin friction of the entire floor introduces losses. The floor edge itself is a source of losses which increase as the floor power increases.
You misunderstood me, I didn't say it doesn't produce drag, I said floor is still the lowest drag element on the car (in mid-high wing downforce configurations, of course). Those turning vanes cause drag, yes, but things are even more complex than that, there are multiple surfaces one behind another, pressure is projected on both sides etc. Overall, mid-high downforce wings still cause more drag.
AR3-GP wrote: ↑15 Sep 2022, 20:58
If you were to kill the the diffuser, you would depower the entire floor. Velocity everywhere is reduced. The losses due to boundary layers, expansions, and turning vanes are reduced are they not? You suggested previously that the RB18 philosophy is that of a flat floor race car w/ a diffuser accelerating the air over flat floor. Using the diffuser to power the floor. Is this not the clue as to the behavior of the car and why stalling the diffuser would reduce drag?
This mechanism was described as the trick for Mercedes last season as well. RB seem to be using the DRS as the on off switch whereas last season Mercedes had to faff about with minimum cornering speeds to tune their system properly (it's like the W13 system targeted the non-DRS straights whereas RB's system targets the DRS straights).
Red Bull would be able to predict the ride height and pitch angle of the car given the fixed front wing load, and the on-off loads of the rear wing at high speed. As you say, the RB18 only exhibits this jet mode when the DRS is open. When the DRS is closed, Ferrari matches them in the straights.
It's a very different situation this year with diffuser design vs last year. The only thing is that diffuser still exists, though some teams made sure it exists in name only. RB is not one of those, but it's still very far from last year.
When you have a flat floor and diffuser, there are strong relations between diffuser ramp angle and ride height - bigger angle requires more ride height. Then, you can introduce 40-50mm rake in the rear and make the whole thing even crazier. With soft suspension you can drop the rear on straights, lower overall frontal area, lower RW AOA and ride height. These factors combined can lead to diffuser stall (to some extent) especially since it was very outwashing design. You also had bunch of vanes in diffuser as well, which also generate less drag when stalled, so there were more benefits than there would've been this year.
Contrary to that, this year you have a design that requires very stable and stiff suspension, to prevent floor chocking mid-corner, you can't introduce so much rake (only RB does, and it's less than 20mm by the looks of it), you can't afford diffuser stall since floor contributes even more to overall downforce than the last 40 years and losing this downforce mid-corner is a one-way ticket to barriers. On top of all that, you have insanely strong beam wings which drive the diffuser extra hard and basically leave no room for any kind of stall.
So I don't see what kind of physics mechanism would be at play here to introduce diffuser stall at high-speed without the risk of it happening mid-corner. As for DRS-triggered stall, I still don't see the mechanism, beam wings are fixed and those are more important to the floor than rear wings. If you have an idea for diffuser stall that works around what I just wrote, please share, that would be a juicy one.
