Aerodynamic performance investigation of sweptback wings with bio-inspired leading-edge tubercles

Abstract

The aerodynamic behavior of sweptback wing configurations with bio-inspired humpback whale (HW) leading-edge (LE) tubercles has been investigated through computational and experimental techniques. Specifically, the aerodynamic performance of tubercled wings with symmetric (NACA 0015) and cambered (NACA 4415) airfoils is validated against the baseline model at various angles of attack ([Formula: see text]. The [Formula: see text]/[Formula: see text] ratio of the HW flipper is strategically reduced to 0.15 for ascertaining the flow control potential of the bio-inspired wings with sweptback configuration. It is a novel effort to quantify the effect of the leading-edge protuberances on stall delay, flow separation control and distribution of streamline vortices at unique [Formula: see text]/[Formula: see text] ratio outside the thickness range of HW flipper morphology. Four tapered sweptback wing models (Baseline A, Baseline B, HUMP 0015, HUMP 4415) are used with the amplitude-to-wavelength ([Formula: see text] ratio of 0.24 and Reynolds number about [Formula: see text]. The chordwise pressure distributions are recorded at the peak, mid and trough regions of the tubercled wings through a detailed wind tunnel testing and validated with numerical analysis. Additionally, the flow characteristics over the bio-inspired surfaces have been qualitatively analyzed through the laser flow visualization (LFV) technique to reveal the influence of laminar separation bubbles (LSBs). The essential aerodynamic characteristics such as boundary layer trip delay, vortex mixing, stall delay, and flow control at different AoA are addressed through consistent experimental data. As the sweptback configuration is a primary choice for airplane wings, the improved aerodynamic characteristics of the tubercled wings can be effectively utilized for the design of novel lifting surfaces, hydroplanes and wind turbines in the near future.

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

“…To ensure a meaningful interpretation of measurements, the static and dynamic pressure correction factors ( k 1 and k 2 ) should be included with tunnel calibration data prior to the validation process. 50,51 If the values of k 1 ≈ 1 and k 2 ≈ 0 with the tolerance limit of ≤ 3%, then the tunnel can be considered as a reliable one for the validation process at low Re regimes with acceptable TI levels. 52 For example, in the present work, the Root Mean Square (RMS) deviation at an AoA of 10⁰ is about 1%.…”

Numerical Study on Aerodynamic and Aeroacoustic Performances of Bioinspired Wings

“…The results show that the airfoil with iron-shaped leading-edge waves presents with highest noise reduction of 14.3 dB, and the change of vorticity induced by biomimetic structures is the suggested cause. Bruce Ralphin Rose et al's [26][27][28][29] group conducted comprehensive reviews toward the biomimetic flow control techniques in the aerodynamic applications. Moreover, the straight and sweptback wings with the humpback whale leading edge tubercles are studied numerically and experimentally, which show enhanced aerodynamic performances.…”