MIKEY_! wrote:Ahhh... how many times must i say it... this does not prevent the vortex but it will lessen the effect and strength. The further you are from the surface of the wing the less the pressure difference between air outside the endplates and air between. The diagonal cut means air wont flow around the top of the endplate at this point. this reduces the vortex. The flows will still interact but in a more laminar manner because they dont flow around (parallel) surface to meet each other.
Behind any finite lifting body there are 3 regions of different pressure - ambient on the outside, (much) lower on the wings suction side and (slightly) higher an the pressure side. How big the differences are depends for the first approx only on the amount of generated lift (load).
Until you separate them with infinite endplates, they will eventually meet and change flows to become either turbulent or vortical (or both).
We tend often to forget, that at low mach numbers (lets say M < 0,3), as is the case with F1 car, these disturbances propagate almost instantly (well, with the speed of sound) in all directions - you can't just leave them behind and forget, they influence the flow in front of the wing and all the way back. That's why we call it induced drag.
You can influence amount of induced drag by controling type of generated disturbances (i.e. low vs high vorticity vortex) - but we are speaking about few percent - 3% of drag reduction from wing tip device is considered very good result in aviation. You have to substrate additional skin friction drag introduced by the endplates/fins/winglets from this.
On the other hand on the finite wing there will always by spanwise component of the flow (due to pressure difference behind the wing - local flows "know" they should start to follow those gradients behind). This means outer parts of the wing become less efficient, flows start to detach and so on ...
Very low aspect ratio of F1 wings make them very prone to those effects - they are very highly loaded, and lost of efficiency on even relatively small area of the wing means lots of downforce get lost.
One way to prevent this is to generate and maintain high vorticity vortex where the wing and enplate meet. High speed, very low pressure core of this vortex helps make outer part of the wing work.
As always it's the question of finding sweet spot between drag and downforce increase, but as we see, all current teams use cutouts, so IMO they go for slightly more drag and more downforce in reward - if not all to the same extend.
