Shock -Expansion technique





The pressures on the airfoil surface can also be calculated using oblique shocks and P-M expansions.

Note: at the trailing edge, there are a few conditions to be met.

  1. same flow direction
  2. same static pressure
on both sides of the slip line

This is the most exact way of calculating forces and moments. It is also the most tedious, but it is necessary for angles > 5° .
 

Second order theory (Busemann's theory)

If we retain terms of the order of  in our expression for ,

This gives better results for , ,  than the linearized theory, but worse results for .