The effect of wavy leading edge modifications on NACA 0021 airfoil characteristics

In spite of its mammoth physical size, the Humpback whale's manoeuvrability in hunting has captured the attention of biologists as well as fluid mechanists. It has now been established that the protrusions on the leading edges of the Humpback's pectoral flippers, known as tubercles, account for this baleen species' agility. In the present work, Prandtl's non-linear lifting-line theory was employed to propose a hypothesis that the favourable traits observed in the performance of tubercled lifting bodies are not exclusive to this form of leading edge configuration. Accordingly, a novel alternative to tubercles was introduced and incorporated into the design of four airfoils that underwent wind tunnel force measurement tests in the transitional flow regime. The experimental results demonstrate similar loading characteristics of the newly designed foils in comparison with those with tubercles, suggesting the presence of an analogous flow mechanism.