Aero on cars entering a tunnel.

[mzivtins]

Hi guys! another one of my brain-farts!

Earlier this week i was coming back from London on the express route into Peterborough. At some point you enter a tunnel and POP your ears go.

So it got me thinking... what would happen to the aerodynamics of an F1 car as it entered a true tunnel?

What i mean by a true tunnel, is one that only has a two holes either end... so to help you guys imagine this, it would be the Monaco tunnel but instead of the left hand side being open, was actually completely walled:


Is this as simple as saying, different densities of air increase or reduce drag etc. Or no effect at all? Just wondering... and i thank you in advance

[ajdavison2]

I think i've heard webber saying that they lose a little bit of downforce upon entering the tunnel causing slightly more sliding. I'm saying more it might only be another half of a degree of slip. I couldn't tell you why though, that would have to be left to one of the more intelligent members of the forum haha.

[mzivtins]

Now that is interesting., you think it could be because the tunnel roof could obstruct the wake of the rear wing/diffuser?

[rjsa]

If it is close enought for this to happen, and I'm not saying it is, it would be a similar case to shallow-water channels for boats but upside down.

In a very pulling from studied 20 years ago theory the body moving immersed in fluid close to a fixed wall will squeeze the fluid between it's boundaries and the fixed wall, accelerating the fluid and reducing the pressure between both surfaces. That would result in a loss of downforce in a racing car. In a boat it results in it being pulled against the bottom.

But then again for this to be sensed one sghould evaluate both speed and clearance to see if the effect is measurable.

It is in fact the very same principle as ground effect.

[DaveW]

Perhaps you should speak to Chip Ganassi Racing people, see this.

[hollus]

It is just the Venturi effect. The air has to move through a constriction, your moving car. If your ears hurt, then there is lower pressure, and the car will feel it as lift, as the floor is still operating in its normal, always obstructed, regime.