Question

How airfoil increases its speed?

(a) Flow over the topside

(b) Flow over the leading edge

(c) Flow over the bottom side

(d) Flow over the trailing edge

I have been asked this question in class test.

My doubt stems from The Kutta Condition topic in chapter Incompressible Flow over Airfoils of Aerodynamics

Answer 1

Right answer is (a) Flow over the topside

Easiest explanation: As the vorticity increases the bound vortex and also progressively increases and causes the flow over the topside of the airfoil to increase in speed. The starting vortex is soon cast-off the airfoil and is left behind, spinning in the air, where the airfoil left it.