[albertobdq]

Ground effect is not banned, just limited from the shape, dimensions and ride height of the bottom of the car allowed by the rules, wich is not the same. Obviously far from what "wing cars" get, but still some thousands newtons of downforce.

I believe that the device over the front wing create some kind on chanel or "air restrictor" for the incomming air going trough the car. If you change the shape or dimensions of this chanel you change pressure/speed of the air over the car, doing this you can turn turbulent flow into laminar and so, reduce drag and/or create downforce. Furthermore, a laminar flow will make easier to achieve a constant vortex.

I'm just wondering...