Local AoA vs. Global AoA

[KUaero10]

I'm working with someone that is struggling with the difference between the angle of attack of an airfoil and the angle of attack of a wing. I've done a horrible job at explaining it to them and was wondering if anyone had a good definition or way of explaining the two so that I could explain it better. And I maybe buggering up my explanation which is causing some of the confusion. Essentially what I tried to explain is that the Global AoA does not represent the local AoA due to Cp variances at the different locations. This leads to the stagnation point changing with its position down the length of the wing.

Thanks for your help

 

[rb1957]

AoA of the wing might be the AoA of the airplane as read by the instruments (corrected for wing installation angle).
But this also varies along the span (consider wash-out); ie not every wing section will have the same AoA.
But the instrument reading is used in practice ... the design engineers determine the airplane's performance in terms of this "global" number, knowing that the different wing stations have different aero performance.

local AoA would/could also include effects of wing deflection (again, something the design engineers would have accounted for in the flight manual of the plane).

clear as mud ?