Farnborough wrote: ↑08 Apr 2023, 20:11
vorticism wrote: ↑08 Apr 2023, 20:08
Neutral in the sense of them not diverting flow adversarially relative to the local domain and as well not inducing vortices, which is to say, aero neutral in the race-car-with-winglets-everywhere sense. As I said just above, the stacking and flow straightening in a wind tunnel isn't relevant to the point I'm making, which is about the existence of situations where cambered wings can exist within a neutral context. Think of it yet another way: tweak the shape one of those stacked vanes and suddenly you end up with a non-neutral wing, to the extent that a flat zero-camber foil suddenly becomes much draggier/liftier (yw) than a heavily cambered foil.
Also your example is not measuring the load on those turning vane at their fixing point within the tunnel structure.
I assure you the wind tunnel in question is fully festooned with the latest of high precision load and pressure metrology equipment. This is a technical forum, after all. However, none of that is relevant.
Another example. Draw a pipe sweep at the angle and radius of your choosing. Now, place an airfoil within it which will cause the least amount of pressure drop. Hint: it will be cambered and not flat, despite flat/zero camber airfoils being assumed as the most neutral.
Now, F1 races aren't conducted inside of tubes (yet) of course. However, ask yourself, why are the pitot arrays they place behind tyres and diffusers always arranged in such jaunty and extreme angles? Without there being any jaunty nor extreme flow conditioners nor turning vanes immediately within there vicinity.