Not just the walls of the wind tunnel. It could be any of several things, for example some of the teams that have built new wind tunnels might still be using code that was written for an older installation (that might be part of the issue with McLaren and Ferrari); the data models for 3rd party items (especially tyres) could also be wrong; data gathering might be faulty etc. In the very worst of cases, someone is getting the math or algorithms wrong (doubtful that can happen in F1 though).godlameroso wrote:Wind can also work differently if you don't have programs and algorithms to account for the pressure distortion that occurs when wind interacts with the walls of the tunnel.beelsebob wrote:Teams are not allowed to operate full scale wind tunnels, only 60% at max. What he means is that air behaves differently over a 60% model than it does over a full sized car. They can do all kinds of things to try and make it behave as similarly as possible, but ultimately they can't make it exactly match how the car will make the air behave.Holm86 wrote:What do you mean by scaling of design?? If you look at the bit you quoted yourself it says full-scale windtunnel. So its not a downscaled version.
Perhaps some teams had better correlation with smaller models because there wasn't as large air displacement that could possibly interact with the tunnel walls.
For McLaren in particular, the data model they had of the old tyres seems to have been wrong, so that while the model behaved well in the wind tunnel, the car experienced porpoising under braking. Without a complete understanding of the physics governing the dynamics of the tyre, I guess teams would simply have lucked into good or bad tyre models. Correlation with the wind tunnel is not to blame, though McLaren has given that as the reason for their below par performance.
Interestingly, now that tyres with firmer sidewalls have been introduced, perhaps McLaren can test the low setup that produced a super quick time at the Barcelona test again (if in season development hasn't veered too far away from it). The car should be able to sit lower now, even under braking.