Question

Is kelvin circulation does not require the dyed circuit?

(a) True

(b) False

I had been asked this question in exam.

This question is from Kelvin’s Circulation Theorem and the Starting Vortex in chapter Incompressible Flow over Airfoils of Aerodynamics

Answer 1

The correct answer is (a) True

To explain: The kelvin circulation theorem does not require the fluid region to be simply connected, it does not require the dyed circuit C to be placed by a surface S  lying wholly in the fluid, this condition is only applied to the vortex shedding off an airfoil.