Wind tunnel technology

[lio007]

Wind tunnels became a talking point in the last couple of years with McLaren, Aston Martin and Red Bull investing in new facilities.

It's hard for me to figure out what is cutting edge technology in the wind tunnel sector. In what kind of aspects is a new wind tunnel better than an old one?

E.g. rolling roads
Does it make sense to use a 3-belt or is Single-belt used across all teams?

[Greg Locock]

The standard deviation of a round robin test on various wind tunnels around the world was ~0.01 for Cd, out of 0.30, and worse (in percentage terms) for lift at each axle.

So yes there is plenty of room for improvement.

[Rodak]

Not to mention the 60% model size limitation; that would seem to possibly create correlation issues.

[peewon]

These two articles are a good insight into how wind tunnels are setup and what requirements are placed on wind tunnel testing under current aero regulations.

https://www.motorsport.com/f1/news/the- ... /10672095/


https://www.motorsport.com/f1/news/how- ... /10671540/

[Tommy Cookers]

These two articles are a good insight into how wind tunnels are setup and what requirements are placed on wind tunnel testing under current aero regulations.
https://www.motorsport.com/f1/news/the- ... /10672095/
https://www.motorsport.com/f1/news/how- ... /10671540/

in the real world wind tunnel correlation actually means wind tunnel correlation
ie they now have full-size in-flight-measured transition points giving correlation to wind tunnel measurement

a wind tunnel model is a model of a fluid mechanics process not eg a model car
(at this generous scale) if the model car is unrepresentative in any way that's not a wind tunnel problem

[lio007]

So the challenge is to interpret the errors best that come along with a 60% model and limited wind speed.

What kind of angles (yaw, pitch and roll) can be tested in nowadays F1 tunnels?
Maybe they can't even afford to test aggressive angles because of the limited amount of test tyres they can use.

[Greg Locock]

They don't use real tires in the wind tunnel, they are just black round things. Well I suppose that is obvious since nobody could make a 60% scale model of a tire that performed at 60%.

[lio007]

They don't use real tires in the wind tunnel, they are just black round things. Well I suppose that is obvious since nobody could make a 60% scale model of a tire that performed at 60%.

They are using special wind tunnel tyres provided by Pirelli.

[lio007]

Silly question: I think all teams use a closed loop tunnel. These tunnels usually have 90° corners and use turning vanes.

What if a wind tunnel is designed in a circle instead of a rectangle? Would it be beneficial?
Although I think manufacturing costs might be quite high.

[TNTHead]

They don't use real tires in the wind tunnel, they are just black round things. Well I suppose that is obvious since nobody could make a 60% scale model of a tire that performed at 60%.

Newey recalls in his book 'how to build a car' that they once had an aerodynamic instability issue due to tire flexing in high speed corners which was overlooked in the wind tunnel with the dummy tires. When they changed the dimension of the dummy tire to simulate the behavior during high speed cornering they were managed to overcome the issue. That was 15 years ago, shouldnt they have improved on such states, or can they check thst woth CFD?

[Hoffman900]

Page 152 https://www.f1-forecast.com/pdf/F1-File ... 2e_all.pdf

And this is basically 20yo information now.

There are scaling issues with the tires and reynolds numbers. You can mimic flex in a static state with pull down rigs in the WT and having rams push on the inside of the tire.

However, a spinning wheel / tire and a static one produces big differences on the entire aero field.

CFD has correlation issues, and to do this correctly you need to model a flexing tire WHILE it is spinning, and that is not simple. Watch a tire in slow motion, it doesn’t just set into one deformed position.