First order analysis of the effect of pitching on the drag coefficient

TLDR: In this paper, a first order analysis was made for the drag coefficient of a pitching NACA 0015 airfoil below stall and it was found that the effect of pitching on the drag coefficients can be approximated by a shift in angle of attack.

Abstract: A first order analysis was made for the drag coefficient of a pitching NACA 0015 airfoil below stall. The inviscid velocity ditribution for a translating NACA 0015 airfoil was superimposed with the additional circulation velocity for a pitching ellipse. The resulting velocity distribution was used to numerically integrate a momentum/boundary layer formulation to obtain the drag coefficient. For both laminar and turbulent boundary layers it was found that the effect of pitching on the drag coefficient can be approximated by a shift in angle of attack. The shift angle was found to be a linear function of the pitching velocity and to be less than the induced angle of attack caused by the pitching.