13 / 20

Which of these statements about the strength of wing tip vortices are correct or incorrect?

I. Assuming no flow separation, the strength of wing tip vortices decreases as the angle of attack increases.
II. The strength of wing tip vortices increases as the aspect ratio increases.

  • A
    I is incorrect, II is incorrect.
  • B
    I is correct, II is incorrect.
  • C
    I is incorrect, II is correct.
  • D
    I is correct, II is correct.

Wing tip vortices are a byproduct of lift. They are caused by the pressure differential between the top and bottom of the wing, which causes an updraft of high pressure air around the tip of the wing. This updraft turns into a downdraft behind the wing, creating a vortex. The higher the pressure difference between the top and bottom of the wing, the stronger the vortices.

This question is specifically asking for:

  • Angle of attack: The strength of the vortices (and therefore also induced drag) is proportional to the angle of attack. Therefore; the strength of the vortices increase as the angle of attack increases, hence statement 1 is incorrect!
  • Aspect ratio: The strength of the vortices is inversely proportional with the aspect ratio. Meaning that the strength of the wing tip vortices decreases as the aspect ratio increases, hence statement 2 is incorrect!

Your Notes (not visible to others)



This question has appeared on the real examination, you can find the related countries below.