Question

Generation of lift is accompanied by a starting vortex at the trailing edge. If the flow is inviscid, this will not happen. What reason can best describe this?

(a) There is no boundary layer formation, hence no vorticity

(b) Kutta Condition is enforced

(c) Kelvin’s Theorem is violated

(d) Starting Vortex dies off instantly

I had been asked this question in my homework.

My question is based upon Kelvin’s Circulation Theorem and the Starting Vortex in section Incompressible Flow over Airfoils of Aerodynamics

Answer 1

Right option is (a) There is no boundary layer formation, hence no vorticity

For explanation I would say: For inviscid flows, the boundary layer is not formed. Therefore, in the regions of high velocity, high viscosity is not there and hence no vortex can form. Thus, there is no lift produced. Starting vortex cannot form in inviscid medium and in the viscous medium it dies due to viscosity.