Influence of vortices on underfloor aerodynamics

[trinidefender]

Is that not the one with a section on diffuser ride height/angles?

It is, but it doesn't talk about rake condition or CoP moving about... Unless i missed those parts. Even if tose parts are present, i suspect they couldn't help us more than our intuition, as the shown experiment are quite basic, generic and...ancient (as 99% of the essays)

As far as I'm concerned, the main idea is that the use features like those seen below is a way for designers to maximize sealing/suction in a way that takes advantage of the naturally occurring parabolic flow structures under the floor.

And i agree with your interpretation. Getting deeper into the topic would be interesting, as the actual behaviour of underfloor airflows is an unknown even to most aero engineers.

Trinidefender mentioned reading about changing of vorticity under certain condition, which is a pretty curious aspect. It would be interesting...

Variante you really do seem to have a knack for misquoting and/or misunderstanding me ya know. At no point did I say that in certain conditions will the vortex change direction. Actually at first look, this idea seems very unlikely.

Still doing some more research but I actually think that there is more to it than is just shown here. Somebody is supposed to run a model for me (who actually has the computing power to do so). At present I don't. From preliminary stuff I have looked at I have seen multiple vortices under the floor, at the floors corner/edge by the flick up and on top the floor going around the bottom of the sidepods. When I can collaborate my findings I'll try to give a through and meaningful post.

[bhall II]

And i agree with your interpretation. Getting deeper into the topic would be interesting, as the actual behaviour of underfloor airflows is an unknown even to most aero engineers.

It's still somewhat exaggerated, and the geometry shouldn't be considered even close to accurate, but this is much more representative of what I have in mind...


Red: bargeboard vortex
Green: other flow
Orange: t-tray channel flow

I don't think there's a huge difference between vented and unvented. The vents just create a pressure gradient near the front of the floor that coaxes air flow under the car to travel along a more advantageous path (they might even contribute a small measure of downforce if air flow is vented as upwash).

If the system produces a better seal, you can add rake, which increases the efficiency of the front wing and the t-tray. By necessity, it would also lift the diffuser. But, the steeper angle should more or less offset any losses associated with the higher ride height.

While visualizing the overall flow patterns, I started to wonder if perhaps the slots commonly found in front of the rear wheels might serve a similar purpose. If they can cause a rearward expansion of the seal's reach, so to speak, that might add a bit of context as to why everybody lost their --- in 2012 when Red Bull showed up to Monaco with a marginally illegal floor...



Even by F1 standards, that saga was weird.

[MadMatt]

Very interesting read and pictures guys, thanks a lot! Very complex indeed when it comes to F1 and vortices management. The fact that we cannot see them makes things difficult for outsiders to understand! =D>

[bhall II]

It's probably best to take my comments with a (liberal) pinch of salt, because I seem to come up with different ideas every time I consider this subject.

[MadMatt]

Don't worry I do, but I sometimes find myself without answers to things I see in F1 aero, so an external opinion is always appreciated.