The objective of the present study is to elucidate the ow mechanism of delaying stall by use of wavy leading edges. Experiments were carried out to examine the effects of variant wavy leading edges attached on NACA0018 section wing of aspect ratio 1.6. The Reynolds number based on the chord length is Rec = 1:38 × 105 for the experiments. For these tests, lift, drag, and moment of wings with and without wavy leading edges were measured in a circular water channel. Flow visualization on the surface of wings was also conducted in order to clarify the e ects of the wavy leading edges on the delaying stall. It is found that the wavy leading edges can control ow separation and delay stall, which in turn is good for producing large lift force at poststall angles of attack. Under the same height condition, the short width of wavy protuberance shows good performance of the wings compared with that of the long width. The wavy protuberance located near the wing tip does not enhance hydrodynamic performance.
