edge, and the flow picture would be distorted. Figure 2 shows the strengths of the wake vortices plotted against the time. In Fig. 3, the unsteady lift components induced by the three vortical regions are plotted separately. These curves show that the most important factor in this blade-vortex interaction is the vortex shedding process. Figure 4 shows the total vortex-induced unsteady lift as compared to the viscous flow solutions given by McCroskey and Goorjian and by Sankar and Tang. The good agreement between the present results and those of others from viscous flow solvers indicates that the present vortex flow model simulates high-Reynolds number attached unsteady flows very accurately.