Artificial ground-effect idea

[manchild]

I'd like to make 3D presentation of another idea of mine, but I'd need to know what should be the minimum height of transverse slit aperture facing air directly, in order not to be choked at high speeds. I'd appreciate any info.

Thanks in advance.

[manchild]

Ok, no one came with a reply, so I made just a quick 3D sketch, just a visual hint of my idea and principle, without exact shape, position or dimensions. Consider it as rough sketch.

I was wondering if having transverse apertures on the floor over-hanged in front of the sidepods, could bring more air under the floor, if the space between the apertures would have stepped snorkels above, which would direct the air into those transverse apertures and below the floor.

Think of it as artificial front end of ground effect airfoil. Diffuser at the rear already does what rear-end of ground effect airfoil is expected, but feeding it with enough air to create similar amount of Venturi effect below the car as in ground effect seasons, became almost impossible after 1982 ban, and flat floor regulations.

Since I'm not aerodynamicist, I've made only a simple model, to visually present the idea to those who know more about than me, or are professionals.



section plane


section plane

[bhall]

Well, allow me to be the first to initiate the time-honored F1Technical tradition of attempting to poke holes in a new idea in order to sink it and thus preserve my personal mastery of the universe. (Saying no is so much easier than saying yes.)

Don't you think the added drag would outweigh the benefits? And would you have to lose the turning vanes on the sidepods due to the rules that essentially require that no part of the bodywork be visible, save for the mirrors, when looking at the car from underneath?

[manchild]

Well, allow me to be the first to initiate the time-honored F1Technical tradition of attempting to poke holes in a new idea in order to sink it and thus preserve my personal mastery of the universe. (Saying no is so much easier than saying yes.)

Don't you think the added drag would outweigh the benefits?

Well, that's the question for professionals I guess. Perhaps a bunch of much smaller slits would give more benefit than drag, or one bigger instead of bunch of small ones. I can't tell that, but perhaps someone with more knowledge can make assessment on spot, without any calculations or CFD.

To be honest, I was hesitating to present this idea for long time, years since I had it, precisely for reasons you've mentioned, but ever since I've seen 2012 cars with brick-sized and brick-shaped nose to chassis transition, it blown the wind in the sails of my self-confidence

[bhall]

In all honesty, you really do come up with the most plausible ideas around here. Your ability to think outside-the-box is kinda eerie.

[Caito]

Let me expose my ignorance, while trying to keep, as bhallg2k said, with F1t tradition.

Isn't the floor shaped sharply(in the edges) so in that way the air won't go from the higher pressure in the top of the floor to the lower pressure in the bottom of the floor, acting as "virtual skirts"? Because air doesn't like to go through rough transitions (or so I read somwehere)

You are feeding the diffuser at the expense of floor surface. So theoretically you'd lose downforce due to losing a piece of the foor(if it's exposed to low pressure the P*A would give downforce), but that would be offset by the decrease in pressure in the floor. Is that your idea?

One more doubt I have, as I see it there is also lift in the holes (but that doesn't mean there could still be net downforce), because you're directing air from the top to the bottom. You create a downwash, if air goes down, car must go up?


PS I'm not saying the idea works or doesn't. I'm in no way qualified to judge that. I'm just trying to understand key concepts behind it.

I guess the easiest way to answer all such questions is doing some CFD tests.

[mx_tifoso]

Are the squared frontal areas a necessity?

And if your drawing is representative of a nearly final version, it seems as if the bargeboards have been removed.

But yeah, it actually wouldn't be surprising at all to see this implemented like your nose slot from a few years back.

[kilcoo316]

Yeah but... no but... maybe.


Uhm, on each vertical face, you'll have a stagnation point (actually a line in the 3D world) - probably more than half the flow will tend to go upward (due to the backpressure from the ground plane).

As the design sits at the moment, I'm not sure whether they're would be a net benefit relative to just one vertical face (say the right-most face in this diagram above).


If you inclined your upper planes (the ones above the triangles), you might encourage further additional flow under the car - but you'd do so by increasing local lift at those upper planes. Not sure what the net effect would be on the car (i.e. would the floor more than balance this out or not).

[horse]

I see what you're thinking, but I'm a bit uncomfortable with those triangular sections. To me they look like rough aerofoils at positive angle of attack which will therefore lift.

I'd be more inclined (no pun intended) to invert the triangles to give a bunch of mini wings with negative angle of attack.

Overall, I'd be a little worried about the impact on the floor leading edge as a whole. This device might move the pressure peak around a bit...

[Just_a_fan]

I'd be more inclined (no pun intended) to invert the triangles to give a bunch of mini wings with negative angle of attack.

I understand your position on this as it's what my initial reaction was. But the idea of this device, if I've understood it correctly, is to fool the air by mimicing the large radius required at the entry of the a traditional ground effect system. So you need to encourage air to flow down under the leading edge of the sidepod. Downforce producing wings will create upwash which is the exact opposite of what is desired here.

One question for the OP though: how much more air can the currently mandated underfloor usefully handle?

[horse]

In the end, this system sees the same frontal area as just the floor leading edge on it's own, so will it really entrain extra air? I can see that you might be able to entrain extra air from above the floor leading edge using the little wings to pull air down but at the cost of generating extra lift in the process.

I'm not experienced enough to say that there would or would not be a net benefit, but my gut feeling is that it looks pretty neutral other than making a bit more drag.

[kilcoo316]

I'd be more inclined (no pun intended) to invert the triangles to give a bunch of mini wings with negative angle of attack.

No can do with the flat floor rule.

[jordangp]

I'd be more inclined (no pun intended) to invert the triangles to give a bunch of mini wings with negative angle of attack.

No can do with the flat floor rule.

Would it be more beneficial to keep the bottom flat then, and have it curved on top instead of a flat slope downwards?

[kilcoo316]

Would it be more beneficial to keep the bottom flat then, and have it curved on top instead of a flat slope downwards?

Like a conventional aerofoil profile with flat underside?


Probably. You'd have to integrate it with the planes above (and upstream/downstream).


I'm sure the diagrams are only to convey the idea and are not representative of a final design!

[hardingfv32]

What rule controls the area that you are proposing to use?

Can the secondary floor actually be expanded forward and have holes in it?

Brian