Ferrari F138

[Froggolo]

To avoid drag increase, could they shape the underside of the nosecone as a NACA inlet
what is known to give minimal disturbance to the airflow?

It could be that De la Rosa testing was just the first step, for checking the basis of this system,
...beside i am just getting crazy to understand where the heck the air is going!

[bhall]

1. I'll get back to you on that one. Until I do, maybe ponder the following in general terms: wheel wake, nose height, and turning vanes under the nose.

2. I think a better way to put that would be to say that the inlet will choke when air pressure within the cavity is equal to or greater than the ambient pressure around the cavity. You could go 1,000,000 MPH, but as long as the system vents the equivalent of 1,000,001 MPH "worth of pressure" along the way - I don't know how else to put it - the system will continue to draw in air. This is why the vent, which is yet to be seen, is so important.

3. Agreed. The vent does indeed have to exit into low pressure. Have I mentioned the low-pressure oasis at the back of the F138?

By the way, what do we think of the idea that duct work from the inlet to, I dunno, a low-pressure oasis in the back of the F138 is accommodated by the chassis...



...right there? (The indentations, not the holes.)

It's admittedly rank speculation, b̶u̶t̶ ̶a̶ ̶v̶e̶r̶y̶ ̶s̶i̶m̶i̶l̶a̶r̶ ̶s̶o̶l̶u̶t̶i̶o̶n̶ ̶w̶o̶r̶k̶e̶d̶ ̶f̶o̶r̶ ̶M̶e̶r̶c̶e̶d̶e̶s̶ ̶l̶a̶s̶t̶ ̶y̶e̶a̶r̶.̶ I'm kidding. We all know nothing really worked for Mercedes last year.

How about a specialized little "diffuser," though?


Constant lower pressure

4. Fair enough.

5. Yes, some numbers would be fantastic. Think Ferrari's willing to give us a loaner on some data?

6. I'm not sure why we're still so singularly focused on shedding the boundary layer. I'll accept the blame for that, though, because of my earlier poor wording.

The whole point of this exercise is to prevent the boundary layer from separating due the adverse pressure gradient after the Venturi. If the inlet reduces any pressure from any source in that area, the boundary layer will benefit from the weaker, or even altogether neutralized, adverse pressure gradient that would normally occupy that spot. That means it won't separate to play hell with the car's aerodynamics downstream.

[AnthonyG]

...beside i am just getting crazy to understand where the heck the air is going!

Into the cockpit?

[beelsebob]

...right there? (The indentations, not the holes.)

Those indentations are so that the engine sits into the step between the reference and step planes, not to let any air flow through.

[Gridlock]

Inevitable Scarbs link:

http://scarbsf1.com/blog1/

"F138 nose slot" article posted.


***Spoiler alert***
antigravity

[amouzouris]

Inevitable Scarbs link:

http://scarbsf1.com/blog1/

"F138 nose slot" article posted.


***Spoiler alert***
antigravity

Thank you...at least someone else agrees with me...'resets' the boundary layer and cooling the driver or kers...

[Froggolo]

...beside i am just getting crazy to understand where the heck the air is going!

Into the cockpit?

hi Anthony
have you the idea of the amount of air such intake can swallow?

[shelly]

I thnikthe inlet is a fix to a f2012 issue: it creates a low pressure area thta nearrows the stream tube and crives the flow between the pylons.
The two turning vanes are the diffuser for the undernose flow - now with the slot you have a sort of double diffuser effect, with the lower lip acting as leading edge. Thus you have a double suction peak: one formed bey the flow that goes into the inlet on the upper lip (probably the duct towards the cockpit is slightly curved up as scabs suggests), and another one formed by the acceleration around the lower lip. The turning vanes act as the strakes in the diffuser, and they sinteract with the two vortices shed by the newly shaped pylons (last year they were straight).

Iirc, last year ferrari struggled a bit with turning vanes under the nose, introducing new versions that did not work, then going back to older version, sometimes having massa and alonso racing with different types.
Now tihe the inlet thay can run more aggressive shapes of the turning vanes without risking their stall

[bhall]

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

[...]

1. I'll get back to you on that one. Until I do, maybe ponder the following in general terms: wheel wake, nose height, and turning vanes under the nose.

[...]

Hey, looks like Scarbs did it for me.

The nose and the raised section of chassis it attaches to creates several issues for the aerodynamicists. Firstly the nose box forms a blockage in between the front wheels and reduces the flow that can pass in the gap between the wheels. Secondly the very high nose\bulkhead designs that are almost universal this year create a high pressure region under the nose\chassis that is effectively creating lift, thus working against the downforce.

He goes on to attribute to skin friction the adverse pressure gradient under the nose that I've attributed to the inherent pressure increase downstream from the Venturi effect of the pylons. Tomato/"tomahto"? Not really, but whatever.

You're right, though, that flow in this area is not confined, and it's that fact which contributed directly to the problem at hand. Because it wasn't confined, it separated when its kinetic energy was "defeated," if you will, by the adverse pressure gradient. The new inlet lessens the adverse pressure gradient, regardless of its genesis, so that the kinetic energy of the boundary layer is "victorious" instead. This means the flow stays attached so that it can be directed rearward by barge boards, vortex generators, and various other widgets designed expressly for that purpose, to then do the dirty work at the rear of the car it was inducted to do in the first place.

Again, everything after that is admittedly rank speculation. But, it's entertaining nonetheless. It's much more fun to imagine possibilities other than just "cooling," yanno?

[AnthonyG]

...beside i am just getting crazy to understand where the heck the air is going!

Into the cockpit?

hi Anthony
have you the idea of the amount of air such intake can swallow?

I know it's a lot, but I think it can be channeled trough the cockpit for earodynamic reasons.

I still find Massa's statement of day 1 of having a bit too hot in the cockpit strange. I think he said it on purpose.

[ringo]

The nose and the raised section of chassis it attaches to creates several issues for the aerodynamicists. Firstly the nose box forms a blockage in between the front wheels and reduces the flow that can pass in the gap between the wheels.

?

The nose box has to be there. It's not a blockage. That's like saying if the wheels were't there....
It's not an issue if it has to be there.

Secondly the very high nose\bulkhead designs that are almost universal this year create a high pressure region under the nose\chassis that is effectively creating lift, thus working against the downforce.

This is very false. This was disproved in 2010. By eye balling it give wrong impressions.

[beelsebob]

Secondly the very high nose\bulkhead designs that are almost universal this year create a high pressure region under the nose\chassis that is effectively creating lift, thus working against the downforce.

This is very false. This was disproved in 2010. By eye balling it give wrong impressions.

Ish... There are known nose designs (e.g. the snowplough) that provide more downforce at the front. It just turns out that rear downforce is what everyone's chasing this year.

[shelly]

Without snowplough you have pressure buildup under the nose. With snowploug you have a channel between nose and snowplough upper surface (pressures compensate by acting in opposite directions) and low pressure on part of the low side of the snowplough due to vortices (like in a delta wing).

Very different situation compared to a normal nose arrangement, in which high pressure on the lower surface creates lift, as bhallg2k correctly says. Ideally you want the pressure to build up a bit downstream , in the keel zone, where you have the tea-tray to compensate for that (opposite pressures again). A strong pressure on the teatray gives you a strong vortex along the y=250 line. The stronger that vortex, the stronger the downforce when it gets accelerated at the sidepod leading edge.
To get low pressure from the tip of the nose to the point of the nose which is after the back of the front wheels you use the shape of the pyolons (which ferrari has taken to an extreme, following waht rbr did first in silverstone 2009, with a channel 500mm wide) and the two undernose turning vanes, which guide the expansion of the undernose flow acting as strakes / diffusers.

Putting the pylons at y=250 on each side allow for guiding and stregthening the y=250 vortex that start from teh intersection between the fia section in the front wing and the outer ppart of the wing, which is more loaded. This vortex is the one that travels along the edge of the teatray (see small tunnels/ strakes there) and then goes under the floor.

[ringo]

There is no pressure "build up" under the high nose.
especially with the 2012-2013 designs.
We've been through this in 2010, when debating the W01 nose. The discussion was settled then, with supporting diagrams.
It's back in the W01 thread.

We need to stop imagining the flow as a 2 dimensional pipe flow.

[henra]

Very different situation compared to a normal nose arrangement, in which high pressure on the lower surface creates lift, as bhallg2k correctly says. Ideally you want the pressure to build up a bit downstream , in the keel zone, where you have the tea-tray to compensate for that (opposite pressures again).

It's not that easy to generally say a high nose creates Lift on the lower side.
That depends on how easy it is for the air to 'esacpe' around the keel and sidepods.
Bernoulli principle applies here as well.
That principle tells you that air at higher speed has decreased static pressure, read decreased lift.
However, i would be too easy (read false) to conclude that the accelerated air will create downforce.
In reality the adverse pressure gradient in front of the keel and sidepods will have an effect upstream. It will deccelerate flow upstream, causing lift elsewhere.
So any blocking ("high pressure") around the keel area will create lift at the forward section of the nose. Therefore you want as little obstruction in the middle section as possible.
If I would have to make a guess I would say a good High Nose should be about neutral. The Gains of this design are clearly at the back of the car. But with the regulations being what they are at the moment that is where it is most desirable.
That's why you see these xtreme high nose deisgn, where in earlier day with different regulations the noses tended to be lower.