Question

Which is the correct statement with regards to the flow over a finite wing?

(a) Local lift is vertical

(b) Downward velocity increases lift

(c) Local lift is inclined to vertical by induced angle of attack

(d) Free-stream velocity causes all the drag

I got this question in an interview for internship.

My question is taken from Downwash and Induced Drag topic in division Flow over Airfoils over Finite Wing of Aerodynamics

Answer 1

Correct choice is (c) Local lift is inclined to vertical by induced angle of attack

The best explanation: Wings have the local lift aligned perpendicular to the local relative wind direction. Thus, it is aligned to the vertical by an angle (called induced angle of attack). The downwash causes this alignment and a component of lift generates what we call induced drag. Thus, lift is deceased.