Question

What is the minimum value of t/c that would result in a detached shock in front of the shape?

Answer 1

Ans. Thickness to chord ratio (t/c) of any shape is primarily the design parameters for bodies flying in air.

In case of airplane/ aircraft design it plays important role in understanding the behavior of flow and results associated with it.

In case of airfoil camber is the maximum distance between the mean camber line and the chord line measured perpendicular to the chord line.

A blunt nose in front create normal shock wave even at subsonic flow. So airfoil are made streamlined in shape to avoid flow separation and resulting shock wave.

The minimum value of t/c that would result in a detached shock in front of the shape is >= 14%

t/c >= 14% have rounded leading edge.

Turbulent boundary layer increases with angle of the attack.

In this flow separation starts from trailing edge, loss of lift is gradual and also pitching moment change is very small.

Hence to get detached shock we must prefer t/c ratio greater than 14%.