Aerodynamic Analysis of Modified NACA 4415 Airfoil with Humpback Whale Tubercles Inspired Leading Edge

The main purpose of this study is to identify the effects of leading edge tubercles that are inspired by the humpback whales on the NACA 4415 airfoil. The interaction between the leading edge tubercles and the freestream flow changes the structure of the flow across the airfoil. Three different airfoils are investigated in this study: baseline NACA airfoil, NACA 4415 airfoil with leading edge tubercles of 5 -mm amplitude and 5 -mm wavelength (Tubercles (1)), and NACA 4415 airfoil with leading edge tubercles of 5 -mm amplitude and 2.5 -mm wavelength (Tubercles (2)). The aerodynamic performances of these three airfoils have been analyzed through computational fluid dynamics (CFD) simulation using the Cradle CFD software. According to the results, both of modified NACA4415 airfoils with leading edge tubercles correspond to better overall aerodynamic performance than NACA 4415 baseline airfoil at Reynold's number of 50,000. At this Reynolds' number, the NACA 4415 airfoil with modified leading edge tubercles increase C L /C Dmax by 16% and decrease C Lmax by 18% and C D by 40% compared to the baseline airfoil. Comparing the leading edge tubercles airfoil to the NACA 4415 airfoil with modified leading edge, Tubercles (2) has demonstrated a 5% decrease in C D and an increase of 8% for C Lmax and C L /C Dmax . This highlights the effects of the smaller wavelength for the tubercles. However, at higher Reynolds' numbers of 100,000 and 200,000, NACA 4415 baseline airfoil has displayed the best overall aerodynamic performance. On the whole, it is taken that the addition of the leading edge tubercles works best at very low Reynolds' number and a smaller wavelength for the tubercles has positive effects.