When a wing generates aerodynamic lift the air on the top surface has lower pressure relative to the bottom surface. Air flows from below the wing and out around the tip to the top of the wing in a circular fashion. An emergent circulatory flow, vortex is induced. Slow and flaps up = larger AoA, then larger pressure difference between lower and upper surfaces.
Not correct.
The lift is constant = weight, larger wing(flaps down) = lower delta pressure required, then less "leakage" from lower to upper.
Last edited by _Phoenix; 15th Nov 2015 at 23:13.
Reason: Added text