Question

What is the condition for Kutta and Joukowski theorem?

(a) Pressure and lift

(b) Pressure and drag

(c) Drag and lift

(d) Lift and moment

This question was posed to me in final exam.

This intriguing question originated from The Kutta-Joukowski Theorem topic in section Inviscid & Incompressible Flow of Aerodynamics

Answer 1

Correct choice is (a) Pressure and lift

The explanation: Kutta and Joukowski discovered that for computing, the pressure and lift of a thin enough airfoil for flow with large enough Reynolds number and at small enough angle of attach the flow can be assumed inviscid in the entire region provided the Kutta condition is imposed.