No doubt there is a great deal of air turbulence in the tunnel for the first few laps of the race
as all the cars go threw at once.
but the tunnel is not full closed on both sides, more then half of it is open to the sea
I would think that most of the aerodynamic effects would be lessened because of this
autogyro wrote:Could the car force air ahead of it through the tunnel?
This would create turbulance at the tunnel exit.
If the car were moving through the tunnel it would. If you stand at a railroad tunnel exit you can feel the air being pushed by an approaching train. But the car in a wind tunnel isn’t moving so it builds static pressure ahead of it.
My cryptic “wind tunnel” comment only (perhaps) makes sense with reference to a line of thought that I neglected to include. The Monaco tunnel effect is interesting but not really worthy of much design effort. However, since a lot of the design is predicated upon wind tunnel testing, the effect of tunnels is important and both warrant and has received much study. My comment rather conflates the two situations.
Tommy Cookers wrote:in Japan (I think) they now have some lines where each track has its individual tunnel, and the train is a close fit in its tunnel
the tunnel needs and has at each end a silencing structure like the silencer on a gun barrel
otherwise there is a big bang
Yes, do a google image search for Shinkansen trains. The nose shape is all a design for this. Drag is not a concern. It's so that when two trains pass each other at well over 200mph(especially In a tunnel) they don't blow out each others windows as they pass through the pressure regions fore and aft.
The force loads on the walls of the tunnel can be quite ridiculous as well when you calculate them out.
I think the problem is less prevalent today because the rear wings in particular are smaller in area, with less planes than years past.
However, I believe the issue is the term known as 'blockage', which is a factor in scale wind tunnels. The upwash hits the roof, which slows the free stream air moving above the model, which then slows the air ahead of it more and more, (think of it actually having to displace the air away, which also means forwards too) which in effect lessens the downforce. the static air pressure will increase a little, which reduces the wings and floors ability to produce a lower pressure. Hence less downforce.
Transfer it to full scale, and the Monaco tunnel presents the same issue. F1 cars are particularly sensitive as they are inherently draggy, with high out wash producing surfaces....
