Sauber C32 Ferrari

[Forza]

BCN T03 - Day 4

[stefan_]

[shelly]

New rear wing on the sauber today, vaguely similar to canada 2010-11 renault (wavy leading edge).

[bar555]

Has anyone noticed the large hole behind the drivers helmet beneath the airbox ? anyone know what its for?

Cooling of some sort.

It's for cooling the airbox itself . Many teams use it since a decade ago

[Forza]

BCN T03-Day 4

[Artur Craft]

nice read about C32 here:
http://www.racecar-engineering.com/cars/sauber-c32/

go directly to the test bits

[Artur Craft]

I wonder which RW will they use in Melbourne: the Jerez one, the "spoon" or the "wavy"

I think they will use the Jerez one but in Sepang and China, I suspect it will be either the spoon or the wavy

Given the team's poor bugdet, I think that's all we gonna see in Australia as even the richer teams don't seem to be bringing much upgrades in 2 weeks time

[hollus]

A little though about the tiny subtlepods: When air goes around them (and all other fully grown sidepods), it is basically going through a constriction and then going back to the original trajectory. This is a bit of an open Venturi channel, not much different from the underside of the wings. It means that the air will accelerate and create low static pressure while going around the convex obstacle.
Now, in more normal sidepods, this (I think) creates lift in the floor, but as there is a downward facing sidepod surface above it, downforce is produced there to neutralize the lift. In the Sauber C32, in the part where the sidepods extend "furthest" to the outside, there is floor, but there is nothing above it. Surely this must have a lift penalty? Of course because there is so little sidepod bulge in the first place, the pressure change (I think) is smaller than in other cars.
Anybody with a full car CFD that can throw in a pressure or velocity plot around sidepods?

[Nando]

This one looks like something you would run at SPA,



Whereas this one is the "main" wing.

[amouzouris]

I think the top one could even be used in 2014 !?!?

[bhall]

A little though about the tiny subtlepods: When air goes around them (and all other fully grown sidepods), it is basically going through a constriction and then going back to the original trajectory. This is a bit of an open Venturi channel, not much different from the underside of the wings. It means that the air will accelerate and create low static pressure while going around the convex obstacle.
Now, in more normal sidepods, this (I think) creates lift in the floor, but as there is a downward facing sidepod surface above it, downforce is produced there to neutralize the lift. In the Sauber C32, in the part where the sidepods extend "furthest" to the outside, there is floor, but there is nothing above it. Surely this must have a lift penalty? Of course because there is so little sidepod bulge in the first place, the pressure change (I think) is smaller than in other cars.
Anybody with a full car CFD that can throw in a pressure or velocity plot around sidepods?

I think...

Maybe if the car was running in a (varry) narrow tunnel. Otherwise, once airflow separates, it's gone, and it's never coming back unless something pushes it back. This scenario would require a (varry) narrow tunnel, like form-fitting.

That's what "incompressible fluid" means in all those rules we read about. You can compress air all day...into a container. Under ambient conditions? Not so much.

(gato azul would be so proud of me right now. Unless I'm all sorts of wrong.)

[R_Redding]

A little though about the tiny subtlepods: When air goes around them (and all other fully grown sidepods), it is basically going through a constriction and then going back to the original trajectory. This is a bit of an open Venturi channel, not much different from the underside of the wings.

I agree .. Also..As I posted earlier , I think that they are losing the effects of downwash on their exhaust layout. Every picture I've seen of the car after a long run shows gasses scorching on the body above the coanda channel .The pioneers of this layout, McLaren ,have a huge top surface to funnel downwash to the exhaust channels on the car this year...

Maybe from a practical point of view, being a midfield team, this car is designed to be a low drag rocket ship that will give them a better chance of podiums in two or three races that suit that configuration.

Rob

[Artur Craft]

A little though about the tiny subtlepods: When air goes around them (and all other fully grown sidepods), it is basically going through a constriction and then going back to the original trajectory. This is a bit of an open Venturi channel, not much different from the underside of the wings. It means that the air will accelerate and create low static pressure while going around the convex obstacle.
Now, in more normal sidepods, this (I think) creates lift in the floor, but as there is a downward facing sidepod surface above it, downforce is produced there to neutralize the lift. In the Sauber C32, in the part where the sidepods extend "furthest" to the outside, there is floor, but there is nothing above it. Surely this must have a lift penalty? Of course because there is so little sidepod bulge in the first place, the pressure change (I think) is smaller than in other cars.
Anybody with a full car CFD that can throw in a pressure or velocity plot around sidepods?

Pressure differences of air going around the sidepods will cancell each other(from side to side). The pressure change will only happen on horizontal plane and not on vertical plane(downforce or lift), ie, only on the sides of the sidepod and not on the top of the floor because air is not going through convex, neither concave, obstacle over the floor plane.

I don't know exactly what you meant about "downward facing sidepod surface", but if it is what I think, then, the sidepod's surface curving downwards will create lift, not downforce.

Actually, it's the downwash of air that creates lift on aircraft's wings. In this link you have lift truely explained and some myths being "busted" by David Anderson(Fermi National Accelerator Laboratory) and Scott Eberhardt (Dept. of Aeronautics and Astronautics ,University of Washington). A really brilliant explanation:
http://www.aviation-history.com/theory/lift.htm

The sidepods, curving downwards, creates lift, not downforce. So, having "less sidepod" there above the floor, will only reduce lift on that area

Donwforce is generated when there is an upwash in air, as you can see with front and rear wings or diffuser, their surfaces all curve upwards, while an aircraft's typical airfoil curves downwards(in it's upper surface)

PS: I hope I understood what you meant there

[bhall]

Generally speaking...

Sidepod lift is classic Bernoulli. There's airflow under the sidepods; there's airflow over and around the sidepods. If the speed of the airflow over and around the sidepods is forced faster than that of the airflow under the sidepods, the resulting pressure-drop over the sidepods will cause lift. This happens.

I'm very comfortable stating that, and I'm not an aerodynamicist. I just play one on F1T.

Airflow over the sidepods is in no way constricted simply because it follows the contour of the sidepods. In that way, airflow over the sidepods is an incompressible fluid. (As is airflow under the car, too.) If something, anything, causes it to separate, it will, and it won't reattach until something else forces it to reattach. Were that airflow genuinely constricted, it physically could not separate. However, such constriction would require the car to be running through a varry tight space, a literal form-fitting tunnel. Truly compressed air tends to live in varry tight spaces compared to its volume in ambient conditions, yanno?


Those scuba tanks hold up to 100 cubic feet of air (and stuff). They are not, however, up to 100 cubic feet in size. Would make diving quite difficult, don't you think?

FYI: Airflow over the boundary layer is not a constriction. If, for any reason, the boundary layer over the sidepod decides it's time for a separation, it's leaving, and it's taking the rest of the airflow above it with it. In that way, the boundary layer is much like the proverbial woman scorned.

The downwash over the sidepods that everyone speaks about these days is related to the use of airflow, vorticies, and various other aerodynamic voodoo to humbly suggest to the exhaust plume that it might wanna stick around and help make some downforce before it gets diffused by other, less helpful airflow, vorticies, and aerodynamic voodoo. (And it's just like a woman to ask for such a favor from "the help" as it's leaving. "Woman, I got things to do: a globe to warm, people to panic. I'm bus-y")

To the real aero docs: please don't shoot me.

EDIT: I've apparently managed to pick up a strange form of dyslexia (denial?), too. That might be one too many cooks in my kitchen.

[hollus]

The pressure change would have effects on both the horizontal and vertical planes, pressure is a scalar magnitude. Below a rear wing, not only is the wing's plane being sucked down, but the end plates are pressed together. In this case the sidepod bulge would be the wing's underplane, the floor one end plate, and the missing top of the sidepod, the second end plate where other cars have the undercut, and it would be, well, missing.
But you are very right that that "missing ceiling" comes hand in hand with less surface in the top of the sidepod, which has its own lift penalty as it bends air downwards. So i guess those two about cancel out and no net lift is created. Still they are left with less downwash for the exhausts, but that is a different phenomenon. I rest my case (kind of defeated).

Edit: @bhallg2k, i am assuming attached flow with no separation here, it will have to accelerate as it fills in the vaccum that would be created (but never is) if it separated. Coanda all over again.