Aerodynamic performance characterization of bio-inspired wings with leading edge tubercles at low Reynolds number

Abstract

On the observation of biomimetic Humpback Whale (HW) flippers, the airfoil aerodynamic performance characteristics are explored. The Leading Edge (LE) tubercle geometry was inspired by the flipper of HW that has rounded LE protuberances and tapered trailing edge configurations. The tubercles have excellent flow control characteristics at the post-stall region. Aerodynamic characteristics of airfoils such as NACA0015 and NACA4415 with LE tubercles are experimentally and numerically investigated at the low Reynolds number about Re = 1.83 × 105. The bio-inspired modified airfoils (HUMP 0015 and 4415) are designed with the amplitude to wavelength ratio [Formula: see text] of 0.05. The numerical simulation over the modified airfoils shows that, at higher Angle of Attack the flow separation is delayed in the peak region whereas the early flow separation is observed in the trough region adjacent to the LE. The boundary layer flow separation analysis is done extensively through numerical simulations and the velocity vector profiles are captured at different chordwise positions. The stall delay phenomenon is observed through the outcome of this research that specifically insists at the peak region of tubercles. Computation of Coefficient of pressure [Formula: see text] distribution is also done by both numerical and wind tunnel experiments. Analysis of [Formula: see text] distribution allows the identification of critical regions that initiate the adverse pressure gradient and region of flow separation. It is a novel effort to predict the Coefficients of Lift [Formula: see text] and Drag [Formula: see text] concerning the bio-inspired airfoils through [Formula: see text] distribution such that the influence of flow separation and vortex distribution are characterized for the modified and baseline airfoils. Comparison of [Formula: see text], [Formula: see text], and [Formula: see text] between the baseline and modified airfoils reveal the enhanced momentum transfer characteristics of bio-inspired tubercles.