Critical Mach number is reached when the pressure coefficient gets to the critical value over the upper side of the airfoil. Then the "pocket" where the flow gets accelerated beyond Mach 1 begins to form. Lift divergence is the relatively rapid increase in drag on the wing due to the normal shock on the surface getting stronger and producing a loss of total pressure. This loss causes a new type of drag called wave drag.
Awesome introductory video, thanks!
And what is lift divergence???
Can someone tell about upper critical and lower critical mach no
Critical Mach number is reached when the pressure coefficient gets to the critical value over the upper side of the airfoil. Then the "pocket" where the flow gets accelerated beyond Mach 1 begins to form. Lift divergence is the relatively rapid increase in drag on the wing due to the normal shock on the surface getting stronger and producing a loss of total pressure. This loss causes a new type of drag called wave drag.