The dynamic behavior of vortices shed from the leading edge of two kinds of pitching airfoils, such as NACA65-0910 and BTE, was visualized by dye flow visualization and schlieren visualization for Re = 4.0 × 103. Moreover, the dynamic lift acting on them was measured by a six-axes sensor in a water tunnel for Re = 4.0 × 104. In case of both airfoils, the reattachment appeared at the higher angle of attack with higher non-dimensional pitching rate. The dynamic behavior of the reattachment depended on the airfoil configuration and the recirculation region was formed by a few discrete vortices. The scale of discrete vortex shed from the leading edge was about one fourth of the chord length and it did not depend on the airfoil configuration. The length of the recirculation region to the chord length determined the number of discrete vortex consisting there. The discrete vortex shedding frequency did not depend on the airfoil configuration, however the dynamic behavior of discrete vortex depended on the airfoil configuration. Moreover, the dynamic lift increased because of the reattachment of the discrete vortices, and the dynamic behavior of discrete vortices influenced much on the dynamic lift.

This content is only available via PDF.
You do not currently have access to this content.