Ferrari F138

[Blackout]

You can't compare using those photos. Ferrari's freed space on the floor is huge. They have probably the smallest sidepods/floor footprint this year, thanks to their almost vertical rads and hight exhaut manifolds.

[Spankyham]

Well, Scalabroni explanation is, on my view, on the short side. It seems logical that a more extreme suspension geometry,, like Ferrari and McLaren's, might lead to an increased tyre consumption per se but, there are 2 points that he might have understimated. 1st, the fact that Ferrari already run an extreme geometry last year and knows pretty much what the downsides are. 2nd, and not least important, that the aero gain they might have with it might increase tyre usage efficiency. More aero efficiency leads to less skid and, therefore, to less shear stress due to lateral movement of the tyre

This is what I thought, more grip, less slippage, better tyre deg. The only thing I'd add is that this years Pirelli's have more rubber on them (a few kgs added). Idea being more rubber to be shed from the tyre before they fall off that cliff - to me that would make less slippage an even better thing.

[bhall]

[...]
Let's just say for now it's a cooling hole. haha.

Well, of course, you can say whatever you like. I'm gonna stick with what I said earlier, because...

...I know that static pressure decreases when a fluid flows through a constricted whatever. I also know that the trailing edges of the F138's wing pylons form just such a constricted whatever. Because I know those things, I'm quite comfortable with the assumption that air flow between the pylons is subject to a Venturi effect. Kosher?

...I know that every instance of a Venturi is punctuated by an increase in static pressure downstream. (Diffusers, anyone?) I also know that this downstream increase of static pressure is the very definition of an adverse pressure gradient for those surfaces that have yet to pass through it, e.g tea tray, splitter, side pods, etc. Still with me?

...I know that skin friction causes the boundary layer to have less kinetic energy than the flow above it. I know that this reduced kinetic energy makes the boundary layer more sensitive to the effects of an adverse pressure gradient, especially in terms of something as "aerodynamically slow" as a car. Furthermore, I know that all pressure gradients tend to want to equalize, which means the (relatively) weak boundary layer will reverse itself (separate) when its kinetic energy is no longer sufficient to overcome the high pressure that characterizes adverse pressure gradients. Don't bail on me now.

...I know that separation increases the effective size of a bluff body, which then increases parasitic drag. I even know that such reduced efficiency intensifies the effects of the adverse pressure gradient, because it allows even more pressure to build as flow decelerates and becomes turbulent.

...I know a great recipe for chili. But, that's neither here nor there.

...I know that teams design cars with high noses, because high noses allow for a higher mass flow rate to the rear of the car. (A little bird told me they do this to increase flow over the diffuser and under the rear wing to create downforce.) Similarly, I know that air cannot efficiently flow over a diffuser and/or under a wing if it's stuck under the nose in a fight against an adverse pressure gradient. Still awake?

...Once again, because I know pressure differentials tend to want to equalize, I know that a low-pressure cavity will bleed pressure away from an area with higher pressure for as long as it somehow maintains lower pressure than the flow it collects.

I still have questions, though. Where is this flow vented? How?

[Artur Craft]

How buky Ferrari's sidepods are compared to Sauber's

I seriously think F138 is gonna eat lot's of C32's dust, at least in some aero tracks.

Could you super impose those?
The ferrari still has more undercut, but i think on the straights the sauber will be the fastest.

Yes, F138 have more undercut, but only when it's reaching the coke bottle area. Before that, C32 also have more undercut than F138.

I'm curious to see if this Ferrari's solution will be succesfull because, imho, that big empty coke bottle area being heavily blocked by those bulky sidepods shouldn't be something good because would cause too much turbulence with airflow.

If Ferrari managed to make this work in a very good way, then applauses to them.

[wesley123]

Yes, F138 have more undercut, but only when it's reaching the coke bottle area. Before that, C32 also have more undercut than F138.

Before that the C32 is much slimmer yes, but they are giving away a large amount of floor area by this solution

I'm curious to see if this Ferrari's solution will be succesfull because, imho, that big empty coke bottle area being heavily blocked by those bulky sidepods shouldn't be something good because would cause too much turbulence with airflow.

And yet they kept the same solution as last year. Last year Ferrari indeed had problems in the area in front of the sidepod which caused problems around the coke bottle. Ferrari fixed that over the course of the season and with that have easily the most advanced bargeboard package/floor in that area.

[shelly]

How buky Ferrari's sidepods are compared to Sauber's

I seriously think F138 is gonna eat lot's of C32's dust, at least in some aero tracks.

Could you super impose those?
The ferrari still has more undercut, but i think on the straights the sauber will be the fastest.

Yes, F138 have more undercut, but only when it's reaching the coke bottle area. Before that, C32 also have more undercut than F138.

I'm curious to see if this Ferrari's solution will be succesfull because, imho, that big empty coke bottle area being heavily blocked by those bulky sidepods shouldn't be something good because would cause too much turbulence with airflow.

If Ferrari managed to make this work in a very good way, then applauses to them.

Probably having a stronger boundary layer will help the flow around the widest part of the sidepos and the slot under the nose is a little help in that direction

[ringo]

..I know that teams design cars with high noses, because high noses allow for a higher mass flow rate to the rear of the car. (A little bird told me they do this to increase flow over the diffuser and under the rear wing to create downforce.) Similarly, I know that air cannot efficiently flow over a diffuser and/or under a wing if it's stuck under the nose in a fight against an adverse pressure gradient. Still awake?

The high nose is not all about the rear of the car. It's about the middle of the car. Yes the rear benefits, which then benefits the rest, but if the middle of the car is poorly designed the car's ultimate potential is reduced.
It's not only about over the diffuser. It's the splitter area and also the front underside of the car. Those horns that you see where the turning vanes are. If you have crappy sidepod design for example, it doesn't matter how high you want to make the nose, you're not going to get good flow around the car.
But to get to some numbers, do you know that the faster the car goes, the smaller the boundary layer?
The boundary layer by the cooling hole is probably a couple milimeters high at around 50mph?
An F1 car is much faster on average than 50mph, and the bl will shrink further, and this is in reference to the distance to that cooling hole. That hole is too tall to shed any boundary layer.
All will do is create a high pressure field under the car,thanks to the restriction to flow inside the tub, and it will create a second boundary layer at it's leading edge. Eventually you have more shear stress on the surfaces and more drag.
If that hole was sucking air, it may have some use, or if there was some kind of surface for the air to push down the car, but it wont be for "boundary layer shedding", it's just too tall.

Also the theories you mentioned, the ingredients, apply to a flat plate, with steady flow. It's going to be different for a curved surface.

[ringo]

While I didn't find an adverse pressure gradient point in my CFD test...i omitted a feature of the nose which is the part close to the front bulkhead just behind the K in Kaspersky where the bodywork gets steeper which would probably produce an adverse gradient point...
However the hole is located exactly where the pressure decreases

http://3.bp.blogspot.com/-VUv-DAgr6Do/U ... le+CFD.jpg

http://1.bp.blogspot.com/-jDhYl6SZnOM/U ... +CFD+1.jpg

http://3.bp.blogspot.com/-hDMLxcCnVGQ/U ... e+CFD2.jpg

Yes this is somewhat correct!
you don't need th rest of the car.

[triart3d]

[youtube]http://www.youtube.com/watch?v=mJybR-uWTUc#![/youtube]
Posible?

Yes.. the ducts attack again.

[bhall]

[Your post]

In no particular order:

Come on, man. Don't ruin this by skimming. I've already said that "peeling" the boundary layer was the wrong way for me to initially describe what I believe this system to be. It reduces volume to reduce pressure. Simple.

The inlet will either allow flow all the time, or it will choke at a certain threshold. This is true regardless of its purpose.

It is absolutely possible for the system to maintain a negative pressure so that it does not choke. It just needs an adequate vent. See: Lotus passive DRS, Mercedes DDRS.

I do not believe the "theories" I posted are only applicable to flat plates. For one thing...


Hi, I demonstrate the Venturi effect.


Oh,yeah? Well, I work with the Venturi effect.


To hell with the lot of you; I save lives with the Venturi effect.
But, ma'am, I don't know that sideburns have ever looked good on a woman. Just throwin' that out there.

The pylons and the underside of the nose are flat anyway.



Did you know that the rear of the car plays a role in how air flows over the front wing and around the sidepods?

Have you noticed the veritable low-pressure oasis that is the F138's rear end? Tell Tombazis his car sucks, and he'll probably say, "Thanks."



McDonnell-Douglas used to build airplanes. Airplanes are really fast, which means boundary layer flow is much more stable because of its higher kinetic energy (higher Reynolds number, actually, but I don't want to go there if I can help it); it can "punch through" adverse pressure gradients. And yet...



And just for old time's sake...



Remember, we're in the waning days of a mature aerodynamic formula, and the grid last year was routinely separated from front to back (minus the "special" teams) by less than a second. Even if this thing is worth only 0.1, Ferrari will gladly take it.

[markp]

Just to help me conceptionalise what you are saying this sounds a similar idea to a double diffuser but at the front. duct air out through a slot to speed up fliw? Are you saying this hole would act like the holes in the side of the streference plain of dd cars to help speed up flow?

[MrCodyWeston]

Sorry, nevermind.

[hairy_scotsman]

How buky Ferrari's sidepods are compared to Sauber's

http://imageshack.us/scaled/landing/341/compartop.jpg

I seriously think F138 is gonna eat lot's of C32's dust, at least in some aero tracks.

Everybody's sidepods are bulky compared to Sauber's.

[ringo]

In no particular order:

Come on, man. Don't ruin this by skimming. I've already said that "peeling" the boundary layer was the wrong way for me to initially describe what I believe this system to be. It reduces volume to reduce pressure. Simple.

Reduces volume? .. why not say density change. The air is not confined.

The inlet will either allow flow all the time, or it will choke at a certain threshold. This is true regardless of its purpose.

It will choke once the air speed outside is much quicker; ie the resistance to flow is higher in the hole, and the path of less resistance will be the underside of the nose.

It is absolutely possible for the system to maintain a negative pressure so that it does not choke. It just needs an adequate vent. See: Lotus passive DRS, Mercedes DDRS.

Yes, but to tell you the truth, 90% of the people who write on ddrs don't know what they are talking about. If we can find that vent then u have something to work with. And that vent needs to exit in low pressure.

I do not believe the "theories" I posted are only applicable to flat plates. For one thing...

I didn't say it only applies to flat plates, the phenomena is different on a curved or angled surface.

The pylons and the underside of the nose are flat anyway.

The airflow is at an angle of incidence. typical flat plate flow is usually taken parallel to the plate.

I'm not commenting on any blog articles, as most of them have no basis. A few numbers would be nice. If not some diagrams from them. And when i say diagrams, labeled diagrams from actual studies.
On this now...

What if that slot was 3 times the height of the boundary layer?
And there was no suction?
What if the surface was upside down, any examples of upside down suction slots at a downward sloping surface?

[hairy_scotsman]

BTW, here's a pic of the F2012 I took in Austin. I don't know if it might help with comparisons to the F138, but who knows: