Aerodynamic Study of Leading-Edge Protuberance to Improve the Performance of NACA 0009 Blade

Symmetric NACA airfoils tend to undergo abrupt stall characteristics at higher angle of attacks. The abrupt stall has deteriorating effect on lift as well as the efficiency of the airfoils. Abruptness in stall restricts the airfoil to operate only at lower angle of attacks. So, in order to improve the efficiency of airfoils at higher angle of attacks and make it suitable for operation over higher range of angle of attacks, there are many flow control techniques. One such technique is addition of leading-edge protuberance. Leading-edge protuberances are the leading-edge modification of the wing. Leading-edge of the wing is modified with sinusoidal structural modification. This modification has two parameters i.e., Pitch and Amplitude. Many configurations of the protuberances can be obtained by changing the Pitch to Amplitude ratio of the protuberance. In the present work, the Reynolds number is 50k for NACA 0009. The Pitch to Amplitude ratio is varied from PAR1 to PAR27. PAR6 is found to be the better case which has higher lift and efficiency in the post-stall angle of attacks. At the deep stalling AOA of the baseline, i.e., at 13.6o, PAR6 is found to have the highest increase in lift and efficiency compared to the other post stalling AOAs with it having around 39.6% more lift and 27.3% more efficiency compared to the baseline.