Question

For an arbitrary inviscid and incompressible flow, with all the body forces zero, what is best described by the given sketch?

(a) Boundary Layer Formation

(b) Kelvin’s Circulation Theorem

(c) Kutta Condition

(d) Generation of Lift

I have been asked this question during a job interview.

Query is from Kelvin’s Circulation Theorem and the Starting Vortex in portion Incompressible Flow over Airfoils of Aerodynamics

Answer 1

Right answer is (b) Kelvin’s Circulation Theorem

Easy explanation: For the same fluid elements in closed curves C1 and C2, the circulation remains constant with time as the fluid elements move downstream. This is essentially Kelvin’s circulation theorem.