question_answer

The critical value of Mach number for a subsonic airfoil is associated with sharp increase in drag due to local shock formation and its interaction with the boundary layer. A typical value of tills critical Mach number is of the order of

A) 0.4 to 0.5                     

B) 0.75 to 0.85

C) 1.1 to 1.3                     

D) 1.5 to 2.0