Abstract
In this study, an unsteady fluid force acting on a disc was measured by using load cell in a wind tunnel at Re numbers 5.0×10^5, 1.0×10^6 and 2.0×10^6. The disc simulates a hand in a periodic pitching motion which is sinusoidal under conditions of several frequencies. Dynamic lift coefficient was compared with the steady one. Moreover, we investigated the ratio between maximum dynamic lift coefficient and maximum steady one versus reduced frequencies. The results showed that the pitching motion can keep the lift even above the steady angle of stall. Higher frequency gives larger unsteady angle of stall. Maximum dynamic lift coefficient depends on reduced frequencies.
