CFD - 2022 Ferrari F1-75 (sidepod analysis)

[jjn9128]

The drag reduction is really obvious when you compare the pressure differences on the face of the rear tyre.

Just to be absolutely clear this is a drag reduction vs my baseline car from ages ago NOT vs any FOM or other geometry. We were aware of some issues in this model but didn't really have time/energy to fix them. I think the bigger take away is where that change in drag came from and the overall change in the flowfield rather than the change in force!

[SiLo]

The drag reduction is really obvious when you compare the pressure differences on the face of the rear tyre.

Just to be absolutely clear this is a drag reduction vs my baseline car from ages ago NOT vs any FOM or other geometry. We were aware of some issues in this model but didn't really have time/energy to fix them. I think the bigger take away is where that change in drag came from and the overall change in the flowfield rather than the change in force!

When you say flowfield, do you mean the overall shape of the flow in that area of the car? I'm guessing the extra "blockage" created by the larger sidepods and their shape are effectively putting a much lower pressure area near the rear tyre, drastically reducing drag in that area?

[jjn9128]

When you say flowfield, do you mean the overall shape of the flow in that area of the car? I'm guessing the extra "blockage" created by the larger sidepods and their shape are effectively putting a much lower pressure area near the rear tyre, drastically reducing drag in that area?

Exactly.

[the EDGE]

When you say flowfield, do you mean the overall shape of the flow in that area of the car? I'm guessing the extra "blockage" created by the larger sidepods and their shape are effectively putting a much lower pressure area near the rear tyre, drastically reducing drag in that area?

Exactly.

does that mean there is a lower pressure in the coke-bottle area too?

[SiLo]

When you say flowfield, do you mean the overall shape of the flow in that area of the car? I'm guessing the extra "blockage" created by the larger sidepods and their shape are effectively putting a much lower pressure area near the rear tyre, drastically reducing drag in that area?

Exactly.

I guess it's a trade off right. A sculpted sidepod to create a larger flowfield creates far less drag than a big rear tyre. But they they sacrifice (potentially) downforce gains elsewhere. Until we get a comparison to something like the Mclaren or Mercedes, we won't know how much better a solution it is.

[tok-tokkie]

This is real F1 Technical.
When I saw the Aston Martin with the huge undercut it seemed to me to be a really good idea. Let the air through - don't get in its way to minimize drag & increase speed.
Then I follow Kyle & the other aero YouTuber & now this. It really has made me appreciate how complex & subtle aero is and how the entire thing must work together. I saw a lovely clear air path but failed to appreciate the failings in other areas.
I really appreciate what you provide. Real F1 Technical. So refreshing when there are so many drivel posts one has to wade through.

[hugobos]

What a wonderful wonderful piece of insight and work
thank you Vanja #66.

[Stu]

When you say flowfield, do you mean the overall shape of the flow in that area of the car? I'm guessing the extra "blockage" created by the larger sidepods and their shape are effectively putting a much lower pressure area near the rear tyre, drastically reducing drag in that area?

Exactly.

does that mean there is a lower pressure in the coke-bottle area too?

If anything it looks as though the Ferrari design has a similar high pressure (but over a comparatively bigger area), certainly at floor level.

[Vanja #66]

Vanja, thank you very much for the great analysis.


I have some questions.
I am a mechanical engineer but feel like an amateur when it comes to aerodynamics.

Could the side pods act like this:

https://i.imgur.com/sc7kyLk.jpg

Low speed - red lines:
May be the tub-sidepod acts like an inverted wing - higher pressure on the upper side. The outer part of the sidepods remind me of airplane wings' "sharklets" preventing the air leaking out, but due to the regulations (minimum body radius), they are rounded.


Over a certain speed the airflow over the side inlet (purple color) detaches and goes over the tub and around the engine cover, thus the need of the vertical cooling gills. The airflow under the inlet seal the floor and outwashes around the rear tires.


Also, because the sidepods look (to me) like inverted wings, would the rake change the angle of attack and influence the down force?

Tub sidepods here are modeled like a motorsport aerofoil - inverted high-camber wing. The "sausages" do exist to keep that air from spilling out (too much) and also for internal cooling purposes.

The air won't detach at certain speed, vertical gills are there because that's where the air goes naturally. It wants to avoid the high-pressure "pool" so it gains an upward direction on the engine cover. Same can be seen on the photo you quoted.

The rake will surely influence these sidepods in a good way, yes, by setting them at higher AoA.

[eyescream]

Vanja, thank you for taking the time to reply to my post.

[Vanja #66]

No problem, we are all here to discuss

[Vanja #66]

As promised, here are the results for W13-like sidepods as well. Once again, I opted mostly for comparisons, that's really the most interesting and the most relevant for us. To avoid any confusion, as we can discuss these concepts only to an extent - since we don't have actual geometries with all the details - let's call them tub-pods and micro-pods.







Both simulations had their problems with various eddies and separations where probably there isn't any. With that in mind, I'm happy that both had roughly the same amount of problematic areas. Micro-pods are really slim and really low drag altogether, lot less than tub-sidepods percentage wise. I've added the rear part of engine cover to sidepod surface to have a better comparison base, I think it can be seen easily.

As can be seen on iso views, the rear tyre of micro-pods has a larger stagnation zone. It naturally had comparatively more drag as well. This was unexpected for me, as micro-pods, just like W13, feature an outwash "flick" along the inlet and I expected this is used to throw the air out and let it hit the tyre. It might as well be that other W13 elements help with this and the overall effect is better, but this is what we have. Sidepod and rear-tyre mixed together - tub-pods are slightly less draggy.



From the top view, the difference is astonishing and one could easily confuse these two cars for completely different series. Micro-pods, being micro, leave a large floor surface exposed, where the air can slow down a bit and build up some pressure to add to the overall downforce. And this is not insignificant over such a large surface.

However, for some reason the top surface of the rear wing generates less downforce, being "less red" This was also unexpected for me and I couldn't find the proper reason for this. Seeing these results gives another angle at why W13 has such a huge rear wing angle over the entire span, along with the huge airbox.



This is a velocity plot at 0.3m above ground, just like before. The difference is huge and very telling on just how different these cars actually are. The way the slow air hits the rear tyre affects a lot of different areas as well, such as diffuser sealing, diffuser and floor overall, maybe even rear wing to some extent.

Overall, micro-pods-car generated more downforce and more drag, for those who believe this information might be valuable. I won't mention downforce and drag percentages and such, but I think it could be noted that the difference in drag is twice as big as the downforce difference - meaning micro-pods-car generated more downforce but with lower downforce/drag ratio.

[LM10]

That’s a fabulous job once again. Thank you Vanja.

And now look at that… the tub-sidepods lead to less overall drag even in comparison to micro-pods! Shows how meaningless it is to look at a car and make claims regarding drag, downforce and other factors.

[Stu]

As promised, here are the results for W13-like sidepods as well. Once again, I opted mostly for comparisons, that's really the most interesting and the most relevant for us. To avoid any confusion, as we can discuss these concepts only to an extent - since we don't have actual geometries with all the details - let's call them tub-pods and micro-pods.

https://i.ibb.co/sqXQXK9/comp1-iso.jpg

https://i.ibb.co/ZgPpS4S/comp-iso-detail.jpg

https://i.ibb.co/R78VY64/comp1-iso-details.jpg

Both simulations had their problems with various eddies and separations where probably there isn't any. With that in mind, I'm happy that both had roughly the same amount of problematic areas. Micro-pods are really slim and really low drag altogether, lot less than tub-sidepods percentage wise. I've added the rear part of engine cover to sidepod surface to have a better comparison base, I think it can be seen easily.

As can be seen on iso views, the rear tyre of micro-pods has a larger stagnation zone. It naturally had comparatively more drag as well. This was unexpected for me, as micro-pods, just like W13, feature an outwash "flick" along the inlet and I expected this is used to throw the air out and let it hit the tyre. It might as well be that other W13 elements help with this and the overall effect is better, but this is what we have. Sidepod and rear-tyre mixed together - tub-pods are slightly less draggy.

https://i.ibb.co/TrBZgbV/comp1-top.jpg

From the top view, the difference is astonishing and one could easily confuse these two cars for completely different series. Micro-pods, being micro, leave a large floor surface exposed, where the air can slow down a bit and build up some pressure to add to the overall downforce. And this is not insignificant over such a large surface.

However, for some reason the top surface of the rear wing generates less downforce, being "less red" This was also unexpected for me and I couldn't find the proper reason for this. Seeing these results gives another angle at why W13 has such a huge rear wing angle over the entire span, along with the huge airbox.

https://i.ibb.co/VLhYhF4/comp1-vplot-0-3m.jpg

This is a velocity plot at 0.3m above ground, just like before. The difference is huge and very telling on just how different these cars actually are. The way the slow air hits the rear tyre affects a lot of different areas as well, such as diffuser sealing, diffuser and floor overall, maybe even rear wing to some extent.

Overall, micro-pods-car generated more downforce and more drag, for those who believe this information might be valuable. I won't mention downforce and drag percentages and such, but I think it could be noted that the difference in drag is twice as big as the downforce difference - meaning micro-pods-car generated more downforce but with lower downforce/drag ratio.

Thank you Vanja, awesome post and great work. Really valuable to help us understand how the flow structures work together.

[cooken]

As promised, here are the results for W13-like sidepods as well. Once again, I opted mostly for comparisons, that's really the most interesting and the most relevant for us. To avoid any confusion, as we can discuss these concepts only to an extent - since we don't have actual geometries with all the details - let's call them tub-pods and micro-pods.

https://i.ibb.co/sqXQXK9/comp1-iso.jpg

https://i.ibb.co/ZgPpS4S/comp-iso-detail.jpg

https://i.ibb.co/R78VY64/comp1-iso-details.jpg

Both simulations had their problems with various eddies and separations where probably there isn't any. With that in mind, I'm happy that both had roughly the same amount of problematic areas. Micro-pods are really slim and really low drag altogether, lot less than tub-sidepods percentage wise. I've added the rear part of engine cover to sidepod surface to have a better comparison base, I think it can be seen easily.

As can be seen on iso views, the rear tyre of micro-pods has a larger stagnation zone. It naturally had comparatively more drag as well. This was unexpected for me, as micro-pods, just like W13, feature an outwash "flick" along the inlet and I expected this is used to throw the air out and let it hit the tyre. It might as well be that other W13 elements help with this and the overall effect is better, but this is what we have. Sidepod and rear-tyre mixed together - tub-pods are slightly less draggy.

https://i.ibb.co/TrBZgbV/comp1-top.jpg

From the top view, the difference is astonishing and one could easily confuse these two cars for completely different series. Micro-pods, being micro, leave a large floor surface exposed, where the air can slow down a bit and build up some pressure to add to the overall downforce. And this is not insignificant over such a large surface.

However, for some reason the top surface of the rear wing generates less downforce, being "less red" This was also unexpected for me and I couldn't find the proper reason for this. Seeing these results gives another angle at why W13 has such a huge rear wing angle over the entire span, along with the huge airbox.

https://i.ibb.co/VLhYhF4/comp1-vplot-0-3m.jpg

This is a velocity plot at 0.3m above ground, just like before. The difference is huge and very telling on just how different these cars actually are. The way the slow air hits the rear tyre affects a lot of different areas as well, such as diffuser sealing, diffuser and floor overall, maybe even rear wing to some extent.

Overall, micro-pods-car generated more downforce and more drag, for those who believe this information might be valuable. I won't mention downforce and drag percentages and such, but I think it could be noted that the difference in drag is twice as big as the downforce difference - meaning micro-pods-car generated more downforce but with lower downforce/drag ratio.

Any reason why the W13 sidepods were placed so far back? From the images I've seen it seems that the inlets should be further forward, in line with the cockpit opening/steering wheel.