Effect of the Reynolds Number on the Performance of a NACA0012 Wing with Leading Edge Protuberance at Low Reynolds Numbers

Effects of smart flap on aerodynamic performance of sinusoidal leading-edge wings at low Reynolds numbers

“…Similarly to Johari et al, 13 wing A produces slightly less drag coefficient than wing B in the poststall regime. However, this is in contrast to what Yasuda et al 27 claimed. They showed that the drag coefficient of sinusoidal leading-edge wings is almost the same as smooth leading-edge ones.…”

“…Therefore, separation at upper surface of leading-edge imposes a negative pressure distribution at troughs. 27 Consequently, these two wings have a higher lift coefficient than wing A after the stall region. Indeed, when the fluid flow reaches sinusoidal leading-edge wings deflects toward the troughs and is separated.…”

“…Therefore, momentum is transferred to the separation region close to troughs and leads to flow reattachment. 27 For the highest Reynolds number, superiority of wing B in comparison with wing A emerges in the poststall region where sinusoidal leading-edge reinforces the flow reattachment particularly in troughs by producing longitudinal vortices while the flow is separated in wing A. However, due to reattachment of flow in higher Reynolds numbers of 40,000 and 58,000 over the wing A, the superiority of wing A is concluded compared to wing B before stall point.…”

“…In the lowest Reynolds number, the peak value observed in Re ¼ 40,000 for wings A and A 1 disappears. As Yasuda et al 27 explained, this is because even at low angles of attack, flow separation happens near the trailing-edge of these wings where the laminar vortices develop. The separation point moves toward leading-edge as the angle of attack further increases.…”

“…They showed that the advantages of sinusoidal leadingedge wings are extended to low angles of attack at low Reynolds number flows. Effects of Reynolds number, ranging from 10,000 to 60,000, on the aerodynamics of a NACA0012 wing with leading-edge protuberance were investigated by Yasuda et al 27 They indicated that for a > 8 � , lift of modified wing increases regardless of Reynolds number variation.…”