Kutta’s Point Regarding Theory of Lift
Kutta gave these three points regarding the theory of lift –
- On the upper surface of the airfoil, the circulatory motion increases the translatory motion. Therefore, high velocity and lower pressure are developed on the upper surface. While on the lower surface, the two motions are opposite. Therefore, low velocity and high pressure are developed on the lower surface with a result of upward thrust.
- For a given at a given angle of attack, the value of circulation around the airfoil is such that the flow leaves the trailing edge smoothly. If the trailing edge angle is finite then, trailing edge is the stagnation point.
- If the trailing edge is cusped (curved), the velocities at top and bottom surface at the trailing edge are finite and equal in magnitude and direction.
Zhukovsky’s Point Regarding Theory of Lift
According to Zhukovsky,
L –> Lift
rho –> Flow density
V –> Flow velocity
K –> Circulation