Slipstream effect of 2021 cars

[hollus]

I don't think the new regulations aim at a more aerodynamic (less draggy) lead car, although it might be due to a couple of cleaner surfaces and the lack of bargeboards, etc.
What they aim to do is to move the disturbed air (turbulence plus forward movement) from the leading car upwards, where the following car won't intercept it. The following car would intercept relatively more calm and slow air that moved in from the sides, and thus lose less downforce. Yes, this should result in less tow, possibly much less tow... at the same distance.
The idea is that the lesser tow will be compensated by entering the straight much closer to the car in front, so that even if, overall, the tow provided by the car in front is 50% smaller everywhere, the following car can be in a region, much closer to the leading car, where it is hopefully two times as strong due to that, so that the effects compensate each other.

I think one thing is missing in the discussion: the current difficulty to pass in a straight (without DRS) is not only because the following car starts so far behind, say 10 car lenghts, that the tow is never enough. It is also because the following car, lacking downforce, accelerates at a later point in the track. Thus, the tow is asked not only to make up for the initial distance, but also for the following car being, say, 15km/h slower at the same point in the track at the beginning of the straight. That initial speed deficit means that half the straight is gone before you even stop losing ground to the car ahead.
The new regs should result in this speed deficit being much smaller, so that the effective length of straight to provide a speed plus from the tow is larger.
IMO.

[mzso]

Wouldn't all the upwash mean that the slipstream is better? All the turbulent air is diverted upwards, doesn't mean it's leaving more of a void behind?

disclaimer - I'm no aero engineer

However, if there is more of a void behind then cars would definitely be losing a lot more downforce closer. The whole thing with there being more downforce for the following car means there is less of a void

Not so sure about this. My impression is that slipstream happens closer and turbulence interferes a long way back.
Sure the lack of air would also decrease downforce, but I'm not sure if that even comes into play in a turn when the cars aren't parallel.

[Andres125sx]

I don't think the new regulations aim at a more aerodynamic (less draggy) lead car, although it might be due to a couple of cleaner surfaces and the lack of bargeboards, etc.
What they aim to do is to move the disturbed air (turbulence plus forward movement) from the leading car upwards, where the following car won't intercept it. The following car would intercept relatively more calm and slow air that moved in from the sides, and thus lose less downforce. Yes, this should result in less tow, possibly much less tow... at the same distance.
The idea is that the lesser tow will be compensated by entering the straight much closer to the car in front, so that even if, overall, the tow provided by the car in front is 50% smaller everywhere, the following car can be in a region, much closer to the leading car, where it is hopefully two times as strong due to that, so that the effects compensate each other.

I think one thing is missing in the discussion: the current difficulty to pass in a straight (without DRS) is not only because the following car starts so far behind, say 10 car lenghts, that the tow is never enough. It is also because the following car, lacking downforce, accelerates at a later point in the track. Thus, the tow is asked not only to make up for the initial distance, but also for the following car being, say, 15km/h slower at the same point in time at the beginning of the straight. That initial speed deficit means that half the straight is gone before you even stop losing ground to the car ahead.
The new regs should result in this speed deficit being much smaller, so that the effective length of straight to provide a speed plus from the tow is larger.
IMO.

Corrected that for you sir

Great explanation btw

[hollus]

No, no, Andres, I mean space.
Is the leadind car gets to floor it in a particular line in the ground, at, say 140kmh, the car behind will reach the same line at, say, 135km/h. Only some meters after that line can the following car floor it, at say 145 km/h (reduced grip). By that point in the tarmac, the leading car might well have been doing 155, and by that point in time it might be doing 160 km/h.
The following car is slower, just after the corner, both in time of day and in lap position comparisons.
If it was only in time we’d be talking of the accordion effect that one can see in MotoGP where the time gaps are constant but the distance gaps grow in every straight and shrink in every corner.

[Wass85]

I just hope they are wise with DRS usage or outlaw it ASAP if the recipe for overtaking is just right with these new regulations.

[mzso]

I just hope they are wise with DRS usage or outlaw it ASAP if the recipe for overtaking his just right with these new regulations.

They can't do it like that. But there's no need to anyway. They can just not specify DRS zones, unless a track really needs it.

[TAG]

The new regulations are flirting with a great balance for what we want to see, closer racing. There's a missing piece however and it's not being addressed. Braking; if you appreciatively decrease the current braking capacity, you significantly increase the burden of getting braking right, it's all on the driver.

This IMO is the piece that would create the winning formula for 2021.

[mzso]

The new regulations are flirting with a great balance for what we want to see, closer racing. There's a missing piece however and it's not being addressed. Braking; if you appreciatively decrease the current braking capacity, you significantly increase the burden of getting braking right, it's all on the driver.

This IMO is the piece that would create the winning formula for 2021.

RB said that it was included in their models and he doesn't think that brake distances are a huge factor.
And Symonds said they're looking into ceramic brakes. But not just for braking distances but because of concern about particulates.

[raymondu999]

I don't think the new regulations aim at a more aerodynamic (less draggy) lead car, although it might be due to a couple of cleaner surfaces and the lack of bargeboards, etc.
What they aim to do is to move the disturbed air (turbulence plus forward movement) from the leading car upwards, where the following car won't intercept it. The following car would intercept relatively more calm and slow air that moved in from the sides, and thus lose less downforce. Yes, this should result in less tow, possibly much less tow... at the same distance.
The idea is that the lesser tow will be compensated by entering the straight much closer to the car in front, so that even if, overall, the tow provided by the car in front is 50% smaller everywhere, the following car can be in a region, much closer to the leading car, where it is hopefully two times as strong due to that, so that the effects compensate each other.

I think one thing is missing in the discussion: the current difficulty to pass in a straight (without DRS) is not only because the following car starts so far behind, say 10 car lenghts, that the tow is never enough. It is also because the following car, lacking downforce, accelerates at a later point in the track. Thus, the tow is asked not only to make up for the initial distance, but also for the following car being, say, 15km/h slower at the same point in the track at the beginning of the straight. That initial speed deficit means that half the straight is gone before you even stop losing ground to the car ahead.
The new regs should result in this speed deficit being much smaller, so that the effective length of straight to provide a speed plus from the tow is larger.
IMO.

Very nice post hollus. Ty for the logic good sir

[raymondu999]

Not so sure about this. My impression is that slipstream happens closer and turbulence interferes a long way back.
Sure the lack of air would also decrease downforce, but I'm not sure if that even comes into play in a turn when the cars aren't parallel.

Why would parallelity be an issue? The cars aero doesnt produce a wake in a parallel line behind them, they produce a wake through the air where they just passed

[Just_a_fan]

I happened upon a youtube video of the 2002 Australian GP t'other day. Interesting because Schumacher was tucked up behind Trulli for a few laps. Even though MS was within 0.2s (I saw 0.12s at one point) behind JT, he couldn't pass him. Coming on to the straight, MS was no.more than three car lengths behind JT but couldn't get a tow sufficient to allow the overtake. MS only got through when JT spun himself in to the wall.

[Juzh]

I happened upon a youtube video of the 2002 Australian GP t'other day. Interesting because Schumacher was tucked up behind Trulli for a few laps. Even though MS was within 0.2s (I saw 0.12s at one point) behind JT, he couldn't pass him. Coming on to the straight, MS was no.more than three car lengths behind JT but couldn't get a tow sufficient to allow the overtake. MS only got through when JT spun himself in to the wall.

Those cars had almost zero drag (compared to these days) and it really made slipsteam very weak. Couple that to a powerfull V10 which nearly always had enough umpf to keep accelerating troughout entire straight and that's the result you get.

I don't think we have to fear a repeat of that in 2021, that would be quite extreme. The engines are also staying the same, and these V6 hybrids are really underpowered during the race for current weight and drag. I think they're not far ahead of the old V8s actually.

[Juzh]

The new regulations are flirting with a great balance for what we want to see, closer racing. There's a missing piece however and it's not being addressed. Braking; if you appreciatively decrease the current braking capacity, you significantly increase the burden of getting braking right, it's all on the driver.

This IMO is the piece that would create the winning formula for 2021.

I don't understand this premise. So what if it's all on the driver? It's the same for everyone. If anything, harder braking is a good change, though I don't think it will change too much. Remember 2014 when braking distances were miles long with cars having truly pathetic levels of downforce? I think we've yet to see better racing since then, and bold moves on the brakes were much more common. IMO 2014 regs took it way too far, cars were basically 200 million dollar F2 cars on steroids, but at least racing was good. Still not as good as in 2011/2012 and even 2013.

[mzso]

Why would parallelity be an issue? The cars aero doesnt produce a wake in a parallel line behind them, they produce a wake through the air where they just passed

I wouldn't be so sure about that. The air flows from the front to the back of the car, which is then blown straight behind.

Those cars had almost zero drag (compared to these days) and it really made slipsteam very weak. Couple that to a powerfull V10 which nearly always had enough umpf to keep accelerating troughout entire straight and that's the result you get.

In response to the 2021 regs one of the commentators mentioned that he has a magazine with an article from the mid nineties where they discuss what should be done, because it's difficult to follow because of all the turbulence. So apparently it's not a new problem. (besides the australian circuit sucks for racing.)
As for V10s. Coulthard mentioned after driving a hybrid F1 car that he never experienced such torque and acceleration with the cars he raced even though they were of similar peak power.

[mzso]

What they aim to do is to move the disturbed air (turbulence plus forward movement) from the leading car upwards, where the following car won't intercept it.

It's far more than that. They also aim to reduce turbulence and make the cars less sensitive to it via "ground effect downforce"

Yes, this should result in less tow, possibly much less tow... at the same distance.

This seams like conjecture presented as fact. I'm doubtful of this.
If the turbulent air is diverted up instead of being ejected in the way of the following car it seems logical that you would get a greater slipstream, with more of a partial vacuum.
But since I don't have a completely accurate airflow simulation running in my head it's impossible to tell what actually happens.
I wish they released an animated simulation of this.