Abstract: Viscous flows past a longitudinally oscillating airfoil at high incidences are investigated for solving the unsteady N-S equations. The emphasis of this study is put on revealing complicated vortex structures in the near wake and their influence upon the force acting on the body for different oscillating frequencies, amplitudes and incidences. The computed results show that larger oscillating frequency and amplitude other than higher incidence havea beneficial effect on the averaging lift.

Key words: dynamic stall, unsteady flow, separation flow, vortex motion