Abstract:

The unsteady laminar flow separation phynomenon near the leading edge of an rapidly pitched airfoil at a constant rate is investigated computationally. The diffential-integral method, which is used to compute zonally unsteady flow field in this paper, can handle any flow region surrounding the airfoil, involving reversed separation lines. The emphasis is on studying flow behavior and features in the vicinity of the separation point, according to computed results. Three airfoil shapes, NACA 0012, NACA 0015 and unsymmetric SIKORSKY SC-1095 are studied. Finally, some relationship between shape factors and the leading edge separation is established, and a practical criterion is proposed.

Key words: unsteady flow, numerical computation, separation flow, separation criterion