Abstract
Unsteady fluid forces acting on a discoid airfoil model in the sinusoidal pitching motions under conditions of several frequencies were measured by using the ring structure 2 elements balance. Furthermore, the vorticity field near the trailing edge of the model was also measured by using an X-type hot wire probe. Dynamic lift/drag coefficients were compared to the steady ones. It is confirmed that the pitching motion is available for keeping lift higher after the separation occurs. The delay of stall for the pitching model is observed and also the value of maximum lift coefficient is greater than the maximum lift coefficient under stationary condition. The dynamic lift acting on a pitching model is strongly influenced by vortices shed from the outer edge of the disk.
