Super circulation: possibility to gain downforce

[Sonic59]

I was thinking about using exhaust energy in race cars. There is an effect called "supercirculation". It can be used when high enegry flow stream is behind aerodynamic surface. Lets compare flow around airfoil with and without jet stream to see how it works.
Simple airfoil (30 m/s):

Now lets create a jet stream behind it like that:

And now lets see what happened (jet stream - 180 m/s):

Its a proven effect (in aviation). Its strength depends on a jet stream angle relative to airfoil, jet stream volume and jet stream speed. It increases lift up to 400%!!! In my CFD calculation lift increased by 100% (I believe its not the limit).
In racing exhaust gas can be used as jet stream.

[Dragonfly]

Next year the exhaust pipes must exit at a predefined point behind the car, but I haven't tried to determine the exact spatial region, neither seen an illustration yet.
Depends on where exactly that would be and other eventual limitations.

[wesley123]

If I understand it correctly you are blowing the trailing edge of the wing? That is out of the trailing edge you blow exhaust gas(or w/e) at an certain angle, by this effectively creating an 'air gurney'? would be quite interesting if this is possible or even effective due to the much lower speeds an F1 car has compared to airplanes

[Sonic59]

If I understand it correctly you are blowing the trailing edge of the wing?

yes. The trailing edge has 1mm gap (airfoil thickness is 30mm) from where jet stream is blown.

[n_anirudh]

Are you using a steady solver?? Can you please replicate the same in a 3D simulation.
Cheers!

[Sonic59]

Are you using a steady solver?? Can you please replicate the same in a 3D simulation.
Cheers!

Solver accuracy may vary +-20%. Anyway it clearly shows effect.
I dont want to do 3d simulation because it needs much more time to finish.
I recently found a website where u can find wind tunnel test data:

[wesley123]

would be cool if we for example could see results on the beam wing for example, or the diffuser, where my guess is it could be really useful

[Dragonfly]

If I understand it correctly you are blowing the trailing edge of the wing?

yes. The trailing edge has 1mm gap (airfoil thickness is 30mm) from where jet stream is blown.

Seems to me it has to do more with the now outlawed F-duct. And I doubt it can be applied with the current rules as long as the jet must come out of the foil itself ( if I understood correctly), not from another source.

[MIKEY_!]

Next year the exhaust pipes must exit at a predefined point behind the car, but I haven't tried to determine the exact spatial region, neither seen an illustration yet.

That was before they decided on periscopes, unless they have gone back to them since.

This is very much like the f-duct or blown wing. As i understand it you could blow the endplate close to the under wing surface, which i have been working with for my own 2012 design (i believe the two closed cross sections rule covers this but the area defined does not extend the the endplate).

[Sonic59]

If I understand it correctly you are blowing the trailing edge of the wing?

yes. The trailing edge has 1mm gap (airfoil thickness is 30mm) from where jet stream is blown.

Seems to me it has to do more with the now outlawed F-duct. And I doubt it can be applied with the current rules as long as the jet must come out of the foil itself ( if I understood correctly), not from another source.

Yes. I think even if it will ba applied by one of the teams, the FIA will ban it next race. I think it can be useful in Le-Mans prototypes.

[dren]

So is that creating a virtual fluid flap, or helping pull the air faster around the wing?

[Sonic59]

So is that creating a virtual fluid flap, or helping pull the air faster around the wing?

Both.

[Tozza Mazza]

Would love to take a look at an analsysis of an F1 rear wing using supercirculation!

Is this possible Sonic59?

Maybe this could be used in F1 via a fan inside the aerofoil, although maybe it's a 'moveable aerodynamic device'

[PNSD]

Has your analysis primarily looked at the flow injection at the trailing edge?

I suppose you already know a great deal of work has been conducted on using flow injection, adding momentum to the boundary layer? Of course these studies have primarily focused on an injection point around 30% aerofoil chords, or around the transition point.

Such things used to be common with A/C however it was weight penalties that killed blown devices such as this.

[Just_a_fan]

Has your analysis primarily looked at the flow injection at the trailing edge?

I suppose you already know a great deal of work has been conducted on using flow injection, adding momentum to the boundary layer? Of course these studies have primarily focused on an injection point around 30% aerofoil chords, or around the transition point.

Such things used to be common with A/C however it was weight penalties that killed blown devices such as this.

Lack of reliability was a concept killer for aircraft too. Having the system fail / become less effective midway through take off, for example, was not popular for rather obvious reasons.

The original Hunting test aircraft used a blown trailing edge just as proposed by the OP of this thread.