2012 Exhaust Blowing & Coanda

[hardingfv32]

If their EBD doesn't work well enough, Red Bull seem to be more fully invested in it than the other teams and will therefore pay a larger price for their mis-step.

They have nothing to worry about because they are not blowing the diffuser.

Fully invested in blowing the diffuser? Half of the exhaust flow is routed to the center of the car. That does not seem very committed to me.

They pay a larger price for what? With the performance advantage they had at the end of last season and the complete insignificance of the exhaust performance this year, the worst they can do if they get the exhaust wrong is fall back to McLaren.

You will never be able to correlate the exhaust performance with the car performance. You guys are highlighting one of two major changes this year and try to make it a game changer. The fact is that the exhaust placement has a very small effect on the cars performance this season.

Brian

[MIKEY_!]

Not quite sure what you're getting at there. Perhaps I haven't explained it properly: in it's extremely simplified form this is essentially an intake mounted after the exhaust exit which routes the gases recaptured by that intake to the diffuser.

[raymondu999]

Can anyone tell me what the regulations ban collection and redirection? I have looked already and found nothing.

That was a tech directive (If we're talking about the same thing). The tech directive was that the exhaust gasses weren't allowed to be "reingested."

[MIKEY_!]

If you believe the diffuser is being blown, then it is either being blown for the entire speed range of the car (more difficult), or it is not being blown for the entire speed range of the car (easier).

If it is not being blown for the entire speed range of the car, then you can either accept what happens, when it happens, or you can try to dictate how and when it happens.

If you are Adrian Newey, I think you do the latter, and try to get a little something extra out of it in the process.

Someone has probably already mentioned this but when the exhaust is directed over the diffuser rather than to the edges (at high speed) the rear ride height is compressed already so sealing the diffuser is not such a big deal (and they don't need the DF as much then anyway).

[MIKEY_!]

Bugger! (sorry mods)

Thanks for that ray, looks as though I shall have to re-build my model a bit

EDIT: May have a solution to this, what if the secondary exhaust pipe (the one which reingests the gasses after the actual exhaust exit) had a opening in it, a very, very thin one, along it's entire length, which would leak only a tiny amount of exhaust but would still technically be open.

[pyrosian]

If you believe the diffuser is being blown, then it is either being blown for the entire speed range of the car (more difficult), or it is not being blown for the entire speed range of the car (easier).

If it is not being blown for the entire speed range of the car, then you can either accept what happens, when it happens, or you can try to dictate how and when it happens.

If you are Adrian Newey, I think you do the latter, and try to get a little something extra out of it in the process.

Wouldn't having variable flow/downforce make the car unstable to drive? I must admit i'm currently thinking that most, if not all the exhaust flow would flow over the diffuser because it sounds way too far fetched to come up with a system that would change the position of the exhaust stream at different speeds. If you had diffuser sealing one minute and not the next exiting high speed corners would be deadly!

[MIKEY_!]

Then calibrate the change point to be above that speed. Anyway the change is unlikely to occur at a single point but rather over a speed/rpm range.

[Crucial_Xtreme]

OK, so the flow starts out going to the vortex area at normal cornering speeds, right?

But the faster the car goes, the more the flow is going to try to go (get pushed) farther aft.

But the design of the sidepods, bridge, etc., keep the flow going to the vortex area.

But at some speed (greater than cornering speed), the flow will no longer make it to the vortex area.

So, at that speed, the flow switches to the other side of the "exhaust splitter" (my term for the area just behind the exhaust channel) and flows down the ramp, causing less drag for the straightaways.

Additional info: This doesn't have to be an all or nothing, "hard" splitter for all the flow. The transition from one path to the other could indeed have some percentage of the flow going both ways, but only at the transition speed range.

Without sounding like a complete dummy, why is the air getting pushed further aft, assuming you mean towards the coke bottle?
This is why I asked you that question last night mate.
Isn't the air coming over the sidepods more plentiful & thus stronger than the air going around the sidepods?

What I'm saying is, wouldn't the air over the top of the sidepods act almost as a barrier to the flow coming around the sidepods(considering it takes slightly longer to get there) hence keeping the airflow on the same path it has at low speeds only higher up(just over brake fin area)??

[bhall]

[My comments made much more sense within the context - and thread - in which they were posted. In the future, please delete my comments outright if they're summarily deemed immaterial to their respective discussions rather than move them and render the thoughts completely neutered. Thank you.]

[flynfrog]

Not quite sure what you're getting at there. Perhaps I haven't explained it properly: in it's extremely simplified form this is essentially an intake mounted after the exhaust exit which routes the gases recaptured by that intake to the diffuser.

that makes more sense. I read it as you would be collecting and saving them

[Adrian Newby]

If their EBD doesn't work well enough, Red Bull seem to be more fully invested in it than the other teams and will therefore pay a larger price for their mis-step.

They have nothing to worry about because they are not blowing the diffuser.

Fully invested in blowing the diffuser? Half of the exhaust flow is routed to the center of the car.

Brian

Wrong. Read my posts immediately previous to this one.

[Crucial_Xtreme]

Wrong. Read my posts immediately previous to this one.

Newby can you answer or explain this? How off track or dead wrong am I?

Without sounding like a complete dummy, why is the air getting pushed further aft, assuming you mean towards the coke bottle?
This is why I asked you that question last night mate.
Isn't the air coming over the sidepods more plentiful & thus stronger than the air going around the sidepods?

What I'm saying is, wouldn't the air over the top of the sidepods act almost as a barrier to the flow coming around the sidepods(considering it takes slightly longer to get there) hence keeping the airflow on the same path it has at low speeds only higher up(just over brake fin area)??

[Adrian Newby]

If you believe the diffuser is being blown, then it is either being blown for the entire speed range of the car (more difficult), or it is not being blown for the entire speed range of the car (easier).

If it is not being blown for the entire speed range of the car, then you can either accept what happens, when it happens, or you can try to dictate how and when it happens.

If you are Adrian Newey, I think you do the latter, and try to get a little something extra out of it in the process.

Someone has probably already mentioned this but when the exhaust is directed over the diffuser rather than to the edges (at high speed) the rear ride height is compressed already so sealing the diffuser is not such a big deal (and they don't need the DF as much then anyway).

Excellent point, Mikey. I was going to mention something along those lines, and how that air could be used to balance the car when it wasn't sealing the diffuser, but my post had already gotten long-winded.

[Adrian Newby]

If you believe the diffuser is being blown, then it is either being blown for the entire speed range of the car (more difficult), or it is not being blown for the entire speed range of the car (easier).

If it is not being blown for the entire speed range of the car, then you can either accept what happens, when it happens, or you can try to dictate how and when it happens.

If you are Adrian Newey, I think you do the latter, and try to get a little something extra out of it in the process.

Wouldn't having variable flow/downforce make the car unstable to drive? I must admit i'm currently thinking that most, if not all the exhaust flow would flow over the diffuser because it sounds way too far fetched to come up with a system that would change the position of the exhaust stream at different speeds. If you had diffuser sealing one minute and not the next exiting high speed corners would be deadly!

It would only happen above the speed of the fastest corners, and even then it could be a "soft" switch that happens progressively and gradually. It is not all or nothing.

Also remember, this is not all of the downforce, or even all of the diffuser we are talking about - only the amount due to sealing that Red bull have been able to claw back. AND downforce - due to wings, diffuser, etc - is already increasing with the square of the speed of the car. You will still have more of it on faster corners than you would on slower corners, even without the sealing.

[cossie]

an explanation from Scarbs f1, clarifies some to me what they are doing, and some seem to be a big gray area

Having used the engine via the exhausts to drive aerodynamic performance for the past two years, exhaust blown diffusers will be effectively banned in 2012. The exhausts must now sit in small allowable area, too high and far forward to direct the exhausts towards the diffuser. The exhausts must feature just two exits and no other openings in or out are allowed. The final 10cm of the exhaust must point rearwards and slightly up (between 10-30 degrees). Allied to the exhaust position, the system of using the engine to continue driving exhaust when the driver is off the throttle pedal has also been outlawed. Last year teams kept the engine throttles opened even when the driver lifted off the throttle for a corner. Then either allowing air to pass through the engine (cold blowing) or igniting some fuel along the way (hot blowing). The exhaust flow would remain a large proportion of the flow used when on the throttle, thus the engine was driving the aero, even when the driver wasn’t needing engine power. Now the throttle pedal position must map more closely the actual engine throttle position, thus if the driver is off the throttle pedal, then the engine throttles must be correspondingly closed.

Blown rear wing (BRW): The exhausts will blow upward to drive flow under the rear wing for more downforce

Teams will be faced with the obvious choice of blowing the exhausts upwards towards the rear wing, to gain a small aerodynamic advantage, when the driver is on the throttle. These Blown Rear Wings (BRWs) will be the conservative solution and certainly will be the first solution used in testing.
However, it’s possible to be aggressive with these exhaust designs too. One idea is blowing the rear wing with a much higher exhaust outlet; this would blow tangentially athte wing profile, which is more effective at increasing the flow under the wing for more downforce. Packaging these high exhausts may cause more problems than gains. But last year’s exhausts passing low and wide across the floor suffered a similar issue, but proved to be the optimum solution.

A more aggressive BRW raises the exhaust and blows tangentially under the wing profile, which is more efficient

Even more aggressive solution would be directing the exhausts onto the vanes allowed around the rear brake ducts. If avoiding the brake cooling inlet snorkel, the fast moving exhaust gas would produce downforce directly at the wheel, which is more efficient than wings mounted to the sprung part of the chassis. However the issue here would be the solution is likely to be so effective, that it will be sensitive to throttle position and rear ride height. If these issues can be engineered out, then this is an attractive solution.

An extreme but legal solution is to blow the exhaust on the rear brake duct fins creating downforce directly at the wheel.