Question

Kutta-Joukowski’s theorem is defined for

• A. lift per unit span on the airfoil
• B. drag per unit span on the airfoil
• C. moment per unit span on the airfoil
• D. thrust per unit span on the airfoil

Hint:

Lift = \(\rho V \Gamma\) per unit span, where \(\Gamma\) is the circulation.

Answer 1

The Correct Option is A

Kutta-Joukowski’s theorem is a fundamental concept in aerodynamics, particularly in the study of airfoils. It provides a mathematical description of the lift per unit span acting on an airfoil when it is placed in a uniform flow. According to this theorem, the lift per unit span (L') on an airfoil can be determined using the equation:

L' = ρU_∞Γ

Where:

• ρ is the fluid density.
• U_∞ is the free-stream velocity.
• Γ is the circulation around the airfoil.

This theorem explains that lift is directly related to the velocity of the fluid, density, and the circulation, which is influenced by the shape and angle of attack of the airfoil. Thus, Kutta-Joukowski’s theorem is specifically defined for the lift per unit span on the airfoil.