Investigation on the Effect of Leading-Edge Tubercles of Multitudinal Airfoils at Low Reynolds Number
Main Article Content
Abstract
On the observation of biomimetic of Humpback Whale (HW) flipper, the aerodynamic performance characteristics are explored. The flipper of HW has rounded leading edge (LE) tubercles and tapered trailing edge configuration. The tubercles have excellent flow control characteristics at the post stall region. Aerodynamic characteristics of NACA airfoils such as NACA 0015 and 4415 with LE tubercles are experimentally and numerically investigated at the Reynolds number about Re=1.83×105. The modified airfoils (BUMP 0015 and 4415) are designed with the amplitude to wavelength ratio (η) of 0.05. The numerical simulation over the modified airfoils shows that, the flow separation is less in peak region and high in trough region because of the counter rotating vortices at high Angle of Attack (AoA). Hence the tubercles effectively suppress the stall through the optimized flow separation behaviour. The important pressure distribution variation over mid, trough and peak regions of modified airfoils are computed for different AoA using a subsonic wind tunnel facility. These values are compared with pressure distribution of baseline airfoils experimentally. The Co efficient of Lift (CL) and Co efficient of Drag (CD) also computed for modified and baseline airfoils to enhance the aerodynamic performance. The stall delay phenomenon is observed through the outcome of the analytical results that insists on peak, trough and medial region. Comparison of Pressure Coefficients (CP) and CL, CD between the base line and modified airfoil reveals the momentum transfer characteristics of tubercles.