Question

Which is the incorrect statement with regards to the flow over an airfoil and a wing?

(a) Flow over airfoil is 2D

(b) Flow over wing is 3D

(c) Airfoils have a component of flow along span

(d) Wings have a component of flow along span

I got this question by my school principal while I was bunking the class.

My question is based upon Downwash and Induced Drag in division Flow over Airfoils over Finite Wing of Aerodynamics

Answer 1

Right answer is (c) Airfoils have a component of flow along span

For explanation I would say: Wings (which by default means finite wings) have a component of flow along span, which gives them 3D characteristics. While airfoils, which are infinite wings, have a 2D flow as the span wise component is absent.