What is the source of wave drag exerted on the supersonic airfoil?
(a) Shock waves
(b) Skin friction
(c) Viscous boundary layer
(d) Trailing vortex
This question was addressed to me in final exam.
I'd like to ask this question from Application to Supersonic Airfoils in division Subsonic Compressible Flow over Airfoils : Linear Theory, Linearized Supersonic Flow of Aerodynamics