General aero discussions

[vorticism]

This is the Stella quote making the rounds.

“I have to admit, and I think most teams should admit the same, that before the new generation of cars touched the ground, we thought that the regulations were quite restrictive,” Stella said as per Motorsport.com.

“But interestingly, as soon as you start the journey, you realise there’s a lot of performance, especially on the floor. This ground effect can be exploited from a technical point of view beyond what I think anybody in Formula 1 would have anticipated.

“If you see the level of sophistication of the geometries, you may see on some cars, especially possibly in the parts facing the ground, so not necessarily very visible, and the complexity of the flow field, and the vertical structures that you want to generate under the car, then these went beyond what the regulations would have expected.

"From a spectacle point of view it means that whoever does a better job, like Red Bull is doing at the moment, can gain a consistent competitive advantage beyond what could have been anticipated."

https://us.motorsport.com/f1/news/red-b ... /10457412/

Just a vague statement typical to a team principal, nothing specific to RB, no mention of 'stacked vortexes.' Nothing revealed, nothing of substance suggested other than, "uh, floor works good." Well, yes; obviously. Take PZ posts with a grain of salt; they're ensconced within confetti text for a reason.

[Vanja #66]

Correct, but it can take quite a while depending on the environmental conditions. Even in a tunnel.
https://i.imgur.com/2RBiuih.png
https://i.imgur.com/tgquyTY.png

Also the join could be a desired effect as two joined vortices can also create complex interactions and increase their strength through mutual reinforcement. This is known as the "vortex merging effect," which can result in a larger and more intense vortex than the sum of its individual parts.

In this case, as you pointed out in the following post, the example is about airplane wingtip and flap vortices in free stream. This is very, very different from vortices forming on the vanes in the floor tunnel. Agreed about the vortex merging, of course.

Having seen the tunnel shapes on the widely circulated RB18 photos, there is a lot of vertical contouring which was absent on other cars. Considering the budget cap and the WT penalty, one would have to imagine that the floor of the RB19 is a derivation of the RB18 floor, not an entirely new concept. Thus I think photos of the RB18 can still provide some qualitative insight.

Most likely, yes.

This is the Stella quote making the rounds.

Thanks for sharing, it's quite an ordinary statement. The way it reads, Stella might also be referring to stacks of curvatures at the front of the bib and inside the diffuser keel. These give the flow some vertical components locally, so it could be as simple as that...

[AR3-GP]

I agree that's very ordinary . It's a nothing statement.

[PlatinumZealot]

This is the Stella quote making the rounds.

“I have to admit, and I think most teams should admit the same, that before the new generation of cars touched the ground, we thought that the regulations were quite restrictive,” Stella said as per Motorsport.com.

“But interestingly, as soon as you start the journey, you realise there’s a lot of performance, especially on the floor. This ground effect can be exploited from a technical point of view beyond what I think anybody in Formula 1 would have anticipated.

“If you see the level of sophistication of the geometries, you may see on some cars, especially possibly in the parts facing the ground, so not necessarily very visible, and the complexity of the flow field, and the vertical structures that you want to generate under the car, then these went beyond what the regulations would have expected.

"From a spectacle point of view it means that whoever does a better job, like Red Bull is doing at the moment, can gain a consistent competitive advantage beyond what could have been anticipated."

https://us.motorsport.com/f1/news/red-b ... /10457412/

Just a vague statement typical to a team principal, nothing specific to RB, no mention of 'stacked vortexes.' Nothing revealed, nothing of substance suggested other than, "uh, floor works good." Well, yes; obviously. Take PZ posts with a grain of salt; they're ensconced within confetti text for a reason.

So disrespectful

You should recognize when an engineer can make inferences from the words of other engineers!

If you cannot mentally envision something, you could simply ask for an explanation, you know.


Anyway...

[atanatizante]

I can't see how two vortices (stacked in whichever way, horizontal, vertical or other) would stay apart inside a low converging tunnel. At one point, and very soon after they come close, they would merge and continue revolving in the direction of the stronger one.

Correct, but it can take quite a while depending on the environmental conditions. Even in a tunnel.
https://i.imgur.com/2RBiuih.png
https://i.imgur.com/tgquyTY.png

Also the join could be a desired effect as two joined vortices can also create complex interactions and increase their strength through mutual reinforcement. This is known as the "vortex merging effect," which can result in a larger and more intense vortex than the sum of its individual parts.

Could it be 2 vortices that are twisting in a spiral manner, something like in the double helix structure of DNA?

These vortices would not interact or merge and would both accelerate at the narrow floor throat thus lowering the pressure into the diffuser in order to increase the downforce ... maybe that`s why we could see those rippled structures in the central diffuser area which in addition could help to airflow diffuser extension ...

And another question is regarding the structure of the external rear wing endplate on the AMR23 car ... as I understand its role is to expand the diffuser airflow and thus run it harder ... so is it allowed to place this structure on the internal or the external side of the diffuser`s vertical fence? then, in addition to that, could it be that the structure has a spiral shape to act like a funnel in order to expand the diffuser`s airflow further?

[PlatinumZealot]

@atanatizante
Stella used the word "vertical" so clearly no large scale spiral motion. The assumed two vortices run along-side each other and do not spiral around each other.

There are quite a bit of ways Newey and Co. are creating a vertical structure. And perhaps if other teams are doing it, RedBull just do it a lot better!

Just rotate the examples below by 90 degrees and play a game of seeing which features on the floor are best fit.

Counter rotating pair via wavy flips


Counter-rotating pair via jet cross stream


Counter pair by impingement

[PlatinumZealot]

I think this is where the magic happens. I already wondered at the beginning of the year what this overlaying structures at the side if the keel area are used for.

https://i.imgur.com/IUGluMD.png

It pretty much matches the vertical flow structure hypothesis....

It's not new but could RedBull have mastered the implementation?

Let's keep on eye on the McLaren.

[organic]

I think this is where the magic happens. I already wondered at the beginning of the year what this overlaying structures at the side if the keel area are used for.

https://i.imgur.com/IUGluMD.png
https://pbs.twimg.com/media/FpocZ-hXoAA ... name=large

This keel has already been discussed in the rb19 thread and in other places. Most of the lines that you're seeing are just where seams/bodywork joins are and there are no aerodynamic devices present other than the twin element bib that is somewhat standard up and down the grid.



And the heavily overweight rb18 was already competitive with flexi-floor + high power F1-75 without the extra bib element.. so we can conclude that it's not the essential component of their floor concept

[AR3-GP]

I think this is where the magic happens. I already wondered at the beginning of the year what this overlaying structures at the side if the keel area are used for.

https://i.imgur.com/IUGluMD.png
https://pbs.twimg.com/media/FpocZ-hXoAA ... name=large

It pretty much matches the vertical flow structure hypothesis....

It's not new but could RedBull have mastered the implementation?

Let's keep on eye on the McLaren.

Red Bull wasn't the first to run the keel diveplane. Aston Martin was.

I still think it's a mistake to believe in silver bullets.

[Big Tea]

I think this is where the magic happens. I already wondered at the beginning of the year what this overlaying structures at the side if the keel area are used for.

https://i.imgur.com/IUGluMD.png
https://pbs.twimg.com/media/FpocZ-hXoAA ... name=large

It pretty much matches the vertical flow structure hypothesis....

It's not new but could RedBull have mastered the implementation?

Let's keep on eye on the McLaren.

Red Bull wasn't the first to run the keel diveplane. Aston Martin was.

I still think it's a mistake to believe in silver bullets.

If they have a supernatural bogie that can not pin down by other means, silver bullets maybe an option.
But mundane problems are fixed by understanding them and working on them.
If they do not start at the beginning and work through until they find the fault, chopping the head off will not work (or not for long anyway)

[CaribouBread]

A short, rapid-fire CFD work by Nelson of no car in particular, just looking at various ideas and interpretations of the 2022 regs.

[vorticism]

It shouldn't be to difficult to provide a mathematical model which proves which one is faster.
Maybe I'll have a go tomorrow.

Just think in extremes.

2 km straight, 2 cars. Both start at 100km/h.

Car 1 reaches 310 km/h after lineair acceleration at the 2 km point (end of the straight).
Car 2 reaches 300 km/h after 0,5 km's and keeps that speeds all the way to the 2 km point (again, end of the straight).

Which one arrives sooner?

No calculation needed here to see it will be car 2 and that it won't even be close.

No calculation needed for this example indeed, but this example is a horrible oversimplification. You should at least make sure both cars use the same amount of energy to get to the 2km point, in your example that's not even close.

Wouldn't make a difference; Marcel's is actually a clever exercise. Drag increases exponentially with speed, therefor greater acceleration is achieved at lower speed. It's easier to run through a 5 cm deep puddle than a 50 cm deep puddle. The only variable in our context is DRS which might alter the deployment curve IF the drag reduction is significant enough (likely not).

[Curbstone]

It makes all the difference. In this simplification car 2 uses much more energy than car 1 so car 2 already has a big advantage and will be faster. Resulting, you cannot conclude method of deployment of car 2 is faster than car 1.



Unfortunately my algebra is lacking a bit, so I had to 'dumb' it down a bit and use a bulk method in a spreadsheet.

- Initial speed of 30 m/s (= 100 km/u)
- Mass of 800 kg
- 25 seconds acceleration, of which 20 with deployment.
- Acceleration is calculated according a = F_pu/M - F_r = 12*1000/M - 1.3/M*v^2 with deployment, and 12*850/M - 1.3/M*v^2 without deployment. **
The formula for Acceleration is simplified since it depends F_pu depends on traction, rpm etc. and F_r depends on rolling resistance etc which is a becomes a bit complicated. However, the accuracy of 1.2*1000/M - 0.1/M*v^2 can be verified based on the general knowledge of acceleration of a F1 car;
- Acceleration from 100-200 takes about 2.2 seconds.
- Top speed is about 350 km/u
The formula satisfies for those conditions, so it should be usable.

**edit. I understand now that F_pu is depending on velocity aswell, according F_pu = P/v, so the calculation of acceleration is not correct.
However, since the formula satisfies for the two boundary condition, I suppose it is somewhat ok-ish.


I considered two options. Option 1 with the 20 seconds deployment at the start, and option 2 with de deployment after 5 seconds. This results in the following graphs.

The gap increases up to maximal 50m, and reduces tot 32m in the final 5 seconds.
It's clear the deployment 1 is more favorable.

[Vanja #66]

This is interesting.
I did a CFD of a simplified model of the bargeboard.
https://pbs.twimg.com/media/Fxstl4dWcAA ... =4096x4096
https://pbs.twimg.com/media/Fxstl4fWIAA ... =4096x4096

Personally, I will always support any effort in race car CFD. However, I think it would be worth pointing out some points in this case:

- simplified geometry is one thing, cutting out the rest of the car is very different - this is a gross oversimplification and practically renders any conclusion void
- the domain is way too small, even if this sidepod model is the only thing to simulate - the domain has to be stretched in all directions enough to make sure the fluid on the boundaries reaches appropriate boundary conditions (and this is a whole different can of worms) and this is especially important for
___- the inlet velocity an pressure and
___- the outlet zero-pressure-gradient boundary condition, while
___- if the rest of the car was included you would need a moving ground condition (no-slip condition is of no use in this case)
- the choice of turbulence model and setting up all the parameters is very important and can only be done correctly if the model was correlated in wind tunnel or on track (preferably an actual model, but something similar is also ok if the CFD is used for illustrative purposes and not to get accurate results to be used later)

These are just the basics and there is a whole lot more needed to do anything remotely close to an illustrative CFD that may be decent enough to go into the details and start examining the flow structures I wholeheartedly support anyone who decide to go and explore this area of CFD application

Since the reply is about CFD mostly, I posted in this appropriate topic.

[Smokes]

Why did the mercedes team continue a bad aero concept for so long. The performance on the track did not tally with the simulation models so something must be off.

did there 1/4 scale tunnel models not show porposiing and floor flexing and how the tyre disortorted under load?

You could run fea and cfd to compute how the body deflects under and aero load but it would use too much computational power.