0-degree incidence Calculations
Considering an airfoil without any incidence, the influence of the Mach number leads to the appearence different shock on the profil.
Depending on the shape of the wing, the schemes are more or less symetric.
For example, with the NACA 12 profil, which is symetric, with no incidence, the schemes are symetric.
Whereas with the profil A the flow is similar graph presented in the subject.
Since Mach number is lower than one, a shock appears on the extrqdos of the wing when a smaller one appears on the intrados. Appears a region before the shock where Mach is greater than one, then after the shock , Mach goes back to a values lower than one.
When the Mach gets greater, the shocks gets bigger on both sides of the wing.
As the Mach number becomes greater than one, a shock appears before the profil, with a region between the shock and the profil at Mach lower than one, than shocks normally appears at the end of then profil.
We simulated the flow around the NACA 12 profil with different Mach number to illustrate these cases:
Calculations with an incidence
Considering a symetric profil, we can get to the same results as with a non symetric one giving an incidence to the flow arriving on the profil: the shock is bigger on the extrados than on the intrados.