I do not understand, why the air above the airfoil travels faster than the air below it? The air above has to travel faster than the air below so that both streams meet simultaneously at the trailing edge --- why do the streams have to meet simultaneously ?
PS : I understand the Bernoulli principle and how the lift is created by the pressure difference and all that.
They have to meet at the same time to keep the overall pressure behind the wing equal. The velocity of the air on the top run relatively faster because it has a greater distance to travel (due to the curvature of the wing) and all in the same time as the air of the bottom. Why the same time, because when the air divides it still has to keep pressure equilibrium behind the wing, causing for the air to be pulled over the top much quicker.
Hope this helps, I asked the same question when introduced to this concept :)
