CFD - 2022 Ferrari F1-75 (sidepod analysis)

[SiLo]

The air is differently-blockaged by each concept.

I was thinking this. Ferrari have cleaner air to the rear wing, and can run a smaller one, but Mercedes may have less drag on it because of blockage further up the car.

[Vanja #66]

I was thinking this. Ferrari have cleaner air to the rear wing, and can run a smaller one, but Mercedes may have less drag on it because of blockage further up the car.

For what it's worth, I'm still sticking to my claim about Ferrari having lower drag than Merc. That Merc mirror wing is very draggy for its size...

I'm getting more intruiged by their design, might try to find the time to model and simulate new sidepods as well...

[codetower]

I was thinking this. Ferrari have cleaner air to the rear wing, and can run a smaller one, but Mercedes may have less drag on it because of blockage further up the car.

For what it's worth, I'm still sticking to my claim about Ferrari having lower drag than Merc. That Merc mirror wing is very draggy for its size...

I'm getting more intruiged by their design, might try to find the time to model and simulate new sidepods as well...

@vanja, First of all, thank you for all the info you've provided!

I wanted to hear your thoughts on this; Could it be that the larger Ferrari side-pods, with the "tub" shape, allows them to rely less on the floor for downforce, which in turn lets them to get a better handle on the porpoising? Seeing "sidepod-less" Mercedes and the porpoising they are having makes me think it'll be more difficult for them to resolve. Whereas the F1-75 can raise the car a bit more, open up gaps in the floor if needed, soften the suspension, and not have to compromise as much downforce. Is there any logic to this theory?

[dialtone]

I was thinking this. Ferrari have cleaner air to the rear wing, and can run a smaller one, but Mercedes may have less drag on it because of blockage further up the car.

For what it's worth, I'm still sticking to my claim about Ferrari having lower drag than Merc. That Merc mirror wing is very draggy for its size...

I'm getting more intruiged by their design, might try to find the time to model and simulate new sidepods as well...

@vanja, First of all, thank you for all the info you've provided!

I wanted to hear your thoughts on this; Could it be that the larger Ferrari side-pods, with the "tub" shape, allows them to rely less on the floor for downforce, which in turn lets them to get a better handle on the porpoising? Seeing "sidepod-less" Mercedes and the porpoising they are having makes me think it'll be more difficult for them to resolve. Whereas the F1-75 can raise the car a bit more, open up gaps in the floor if needed, soften the suspension, and not have to compromise as much downforce. Is there any logic to this theory?

Ferrari has visibly less wing than the Merc, both front and rear wing and yet they are clearly the best at the slowest speed corners (last braking, first on throttle). Relying less on the floor for downforce means having a more draggy car because it would mean you need more wing. It's hard to know exactly why Merc hasn't gotten to the bottom of this issue yet, they've not tried many floors and may be unwilling to take any other compromise preferring to porpoise for a race or two instead. I doubt it's related to the shape of the sidepods, that's only an issue because it made Merc waste an entire pre-season test.

[CrossPorpoises]

@Vanja #66, firstly thank you not only for the absolutely amazing post but also for the hugely valuable replies and all the further work that has gone into them.

I have been pondering the effect of the wider flowfield from the F1-75 on the integrity of the underfloor airflow.

As we know the perfect solution to sealing the underfloor is a side skirt, which is of course not permitted.

The flowfield of the F1-75 seems to be outwashing lower speed air, which as has been onbserved has benefits for rear tyre drag. The narrow bodied W13 on the other hand seems partly designed to try to keep this air inboard, to create additional downforce acting on the upper surface of the floor.

Do you think it is possible that one of the benefits of the F1-75 design is that the flow of this air going outboard acts as a kind of aerodynamic side skirt, helping to protect the undefloor flow from fluctuations? A kind of "air curtain" if you will?

If that is true it would help explain the F1-75 having more stable underfloor performance, and perhaps also why the W13, without the protection of this "air skirt", is more affected by porpoising. Possibly also why the W13 is more affected compared to other intermediate designs like the RB, AM etc., since those other designs would also encourage more low speed flow off the side of the car (albeit not to the same extent as the F1-75).

Once more thanks for all your hard work!

[Vanja #66]

I wanted to hear your thoughts on this; Could it be that the larger Ferrari side-pods, with the "tub" shape, allows them to rely less on the floor for downforce, which in turn lets them to get a better handle on the porpoising? Seeing "sidepod-less" Mercedes and the porpoising they are having makes me think it'll be more difficult for them to resolve. Whereas the F1-75 can raise the car a bit more, open up gaps in the floor if needed, soften the suspension, and not have to compromise as much downforce. Is there any logic to this theory?

I really don't see how this could be the case, to be honest. F1-75 sidepod top is a compromise to recover a very small part of DF lost by having them so wide, which is incomparable to DF created by lower floor surface(s). Sidepods generate lift, they can't generate DF within these regulations and even if they could - they'd compromise the rear wing, beam wing and diffuser massively. So no team would choose to do that.

@Vanja #66, firstly thank you not only for the absolutely amazing post but also for the hugely valuable replies and all the further work that has gone into them.

I have been pondering the effect of the wider flowfield from the F1-75 on the integrity of the underfloor airflow.

As we know the perfect solution to sealing the underfloor is a side skirt, which is of course not permitted.

The flowfield of the F1-75 seems to be outwashing lower speed air, which as has been onbserved has benefits for rear tyre drag. The narrow bodied W13 on the other hand seems partly designed to try to keep this air inboard, to create additional downforce acting on the upper surface of the floor.

Do you think it is possible that one of the benefits of the F1-75 design is that the flow of this air going outboard acts as a kind of aerodynamic side skirt, helping to protect the undefloor flow from fluctuations? A kind of "air curtain" if you will?

If that is true it would help explain the F1-75 having more stable underfloor performance, and perhaps also why the W13, without the protection of this "air skirt", is more affected by porpoising. Possibly also why the W13 is more affected compared to other intermediate designs like the RB, AM etc., since those other designs would also encourage more low speed flow off the side of the car (albeit not to the same extent as the F1-75).

Once more thanks for all your hard work!

Well, things aren't working exactly like you mentioned, the airflow is a bit more complex, but the overall conclusion might not be far from the truth. All in all, teams are making better use of venturi-tunnel floors by sealing them with massive outboard vortices on the floor. This is, in a way, the "air curtain" you mention. Prior to Barcelona testing, I was convinced some teams might even be able to include a bit of rake on their cars, seeing how good they were to use it even with previous "simpler" floors. This is not the case yet, but we might see this development in the future... Anyway, these are the vortices I mentioned.



The stronger they are, the better the sealing in general. They are generated by incoming high-pressure air from the front vanes under the floor and lower pressure air on top of it. This might sound counter-intuitive, but this area of the bottom of the floor is a high-pressure zone. Here's a look from the early-W13 micro-pods model CFD results.



Now, if the flow on top of the floor is not favuorable enough (not enough pressure, not enough outwash etc) the resulting vortex might not be good enough. Here is where there might be a difference between race-spec W13 with new sidepods and other cars, as W13 might not produce enough outwash or the pressure is not good enough. If that was the case, a car would probably have to run lower than others and this low ride height would induce the bouncing, I guess much more than vortex sealing could. The new W13 sidepod design is actually better in terms of how wide the flow is going now, the outwash, you can see here.

Here's a top view of the flow-viz on Merc's sidepod undercut, also from AMuS. Seems like the outwash was no weaker due to the inlet itself being a stagnation zone, but Merc was probably trying to avoid having the high-static-pressure undercut flow flipping over the sidepod's outer spline with such a bottom-wide design.

The outwash looks strong enough, but the pressure zone ahead of the Mercedes intake is different from the pressure zone in this area on all other cars, since no other car has an inlet going all the way down to the floor. This may make a difference in the floor sealing on Mercedes, meaning they have to run their car lower to achieve the needed downforce, meaning they are more prone to bouncing than others.

[bomskok101]

I was thinking this. Ferrari have cleaner air to the rear wing, and can run a smaller one, but Mercedes may have less drag on it because of blockage further up the car.

For what it's worth, I'm still sticking to my claim about Ferrari having lower drag than Merc. That Merc mirror wing is very draggy for its size...

I'm getting more intruiged by their design, might try to find the time to model and simulate new sidepods as well...

Toto just confirmed in his interview in response to a question on the Ferrari’s PU power that their data shows the Merc carries the most drag. You predicted it

[holeindalip]

I wanted to hear your thoughts on this; Could it be that the larger Ferrari side-pods, with the "tub" shape, allows them to rely less on the floor for downforce, which in turn lets them to get a better handle on the porpoising? Seeing "sidepod-less" Mercedes and the porpoising they are having makes me think it'll be more difficult for them to resolve. Whereas the F1-75 can raise the car a bit more, open up gaps in the floor if needed, soften the suspension, and not have to compromise as much downforce. Is there any logic to this theory?

I really don't see how this could be the case, to be honest. F1-75 sidepod top is a compromise to recover a very small part of DF lost by having them so wide, which is incomparable to DF created by lower floor surface(s). Sidepods generate lift, they can't generate DF within these regulations and even if they could - they'd compromise the rear wing, beam wing and diffuser massively. So no team would choose to do that.

@Vanja #66, firstly thank you not only for the absolutely amazing post but also for the hugely valuable replies and all the further work that has gone into them.

I have been pondering the effect of the wider flowfield from the F1-75 on the integrity of the underfloor airflow.

As we know the perfect solution to sealing the underfloor is a side skirt, which is of course not permitted.

The flowfield of the F1-75 seems to be outwashing lower speed air, which as has been onbserved has benefits for rear tyre drag. The narrow bodied W13 on the other hand seems partly designed to try to keep this air inboard, to create additional downforce acting on the upper surface of the floor.

Do you think it is possible that one of the benefits of the F1-75 design is that the flow of this air going outboard acts as a kind of aerodynamic side skirt, helping to protect the undefloor flow from fluctuations? A kind of "air curtain" if you will?

If that is true it would help explain the F1-75 having more stable underfloor performance, and perhaps also why the W13, without the protection of this "air skirt", is more affected by porpoising. Possibly also why the W13 is more affected compared to other intermediate designs like the RB, AM etc., since those other designs would also encourage more low speed flow off the side of the car (albeit not to the same extent as the F1-75).

Once more thanks for all your hard work!

Well, things aren't working exactly like you mentioned, the airflow is a bit more complex, but the overall conclusion might not be far from the truth. All in all, teams are making better use of venturi-tunnel floors by sealing them with massive outboard vortices on the floor. This is, in a way, the "air curtain" you mention. Prior to Barcelona testing, I was convinced some teams might even be able to include a bit of rake on their cars, seeing how good they were to use it even with previous "simpler" floors. This is not the case yet, but we might see this development in the future... Anyway, these are the vortices I mentioned.

https://i.ibb.co/jVtrCfm/Mc-Laren-inverted-1536x864.jpg

The stronger they are, the better the sealing in general. They are generated by incoming high-pressure air from the front vanes under the floor and lower pressure air on top of it. This might sound counter-intuitive, but this area of the bottom of the floor is a high-pressure zone. Here's a look from the early-W13 micro-pods model CFD results.

https://i.ibb.co/ZdNqFWB/cp2-w13-closed-bottom.jpg

Now, if the flow on top of the floor is not favuorable enough (not enough pressure, not enough outwash etc) the resulting vortex might not be good enough. Here is where there might be a difference between race-spec W13 with new sidepods and other cars, as W13 might not produce enough outwash or the pressure is not good enough. If that was the case, a car would probably have to run lower than others and this low ride height would induce the bouncing, I guess much more than vortex sealing could. The new W13 sidepod design is actually better in terms of how wide the flow is going now, the outwash, you can see here.

Here's a top view of the flow-viz on Merc's sidepod undercut, also from AMuS. Seems like the outwash was no weaker due to the inlet itself being a stagnation zone, but Merc was probably trying to avoid having the high-static-pressure undercut flow flipping over the sidepod's outer spline with such a bottom-wide design.

https://imgr1.auto-motor-und-sport.de/G ... 880226.jpg

The outwash looks strong enough, but the pressure zone ahead of the Mercedes intake is different from the pressure zone in this area on all other cars, since no other car has an inlet going all the way down to the floor. This may make a difference in the floor sealing on Mercedes, meaning they have to run their car lower to achieve the needed downforce, meaning they are more prone to bouncing than others.

Great explanation.Weren’t they still porpoising with the Barcelona spec sidepods though?

[Vanja #66]

Toto just confirmed in his interview in response to a question on the Ferrari’s PU power that their data shows the Merc carries the most drag. You predicted it

Thanks for the info, is there an article about it or did he say it on TV?

Great explanation.Weren’t they still porpoising with the Barcelona spec sidepods though?

I mentioned this in that post, I think their new design is better than original for outwash on the front of the floor.

[bomskok101]

Toto just confirmed in his interview in response to a question on the Ferrari’s PU power that their data shows the Merc carries the most drag. You predicted it

Thanks for the info, is there an article about it or did he say it on TV?

Great explanation.Weren’t they still porpoising with the Barcelona spec sidepods though?

I mentioned this in that post, I think their new design is better than original for outwash on the front of the floor.

Here we go:

https://www.gpblog.com/en/news/106568/w ... -else.html

[Vanja #66]

Here we go:

https://www.gpblog.com/en/news/106568/w ... -else.html

Thanks!

[LM10]

Toto just confirmed in his interview in response to a question on the Ferrari’s PU power that their data shows the Merc carries the most drag. You predicted it

Thanks for the info, is there an article about it or did he say it on TV?

Great explanation.Weren’t they still porpoising with the Barcelona spec sidepods though?

I mentioned this in that post, I think their new design is better than original for outwash on the front of the floor.

I find it really cool how your CFD analysis was spot on in regards of drag due to sidepod concept. And I also find it cool that some people who attacked you for supposed flaws in your model and at the same time claimed the opposite just because car A "looked" (!) draggier than car B must feel awkward now.

[Vanja #66]

Don't really know about the second part, but I'm glad there is a statement from one team regarding aero performance. Something real we can take into account from now on and observe and compare other things based on that.

[Andi76]

Don't really know about the second part, but I'm glad there is a statement from one team regarding aero performance. Something real we can take into account from now on and observe and compare other things based on that.

Totos explanaition that they have to run their car lower to extract aero-performance goes hand in hand with your explanaition of what might be their problem! You probably are totally right about what is Mercedes problem and i think its fair to say its probably an aerodynamical one.

[Vanja #66]

Totos explanaition that they have to run their car lower to extract aero-performance goes hand in hand with your explanaition of what might be their problem! You probably are totally right about what is Mercedes problem and i think its fair to say its probably an aerodynamical one.

Well, it was evident Mercedes is holding on to low ride height a lot more than other teams, they wanted to try whatever else they could to solve their bouncing issues. It could only mean they depend on low ride height for performance. What also comes to my mind is their suspension design, maybe they designed their suspension for low ride height and raising it too much hurts them and takes away setup margin here and there.