For pure pitching motion, the results show that average drag coefficient decreases as airfoil thickness is reduced.
在低雷诺数条件下，对于纯俯仰运动，随着翼型厚度的减小，平均阻力系数也变小。
2
As airfoil thickness is increased, the average pressure drag, affected by leading edge vortex is reduced even to be negative, and meanwhile friction has little increase.
由于前缘涡的影响，翼型厚度增加，平均压差阻力系数变小，甚至会出现负值。
3
A numerical method is given to calculate the unsteady lift, pitching moment and drag acting on an airfoil of rotors under attached-flow conditions in a compressible flow.