Investigation of sharp change in the lift of a thick teardrop airfoil at low Reynolds numbers
M.A. Akimov1,2, P.A. Polivanov1,2
1Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk, Russia
2Novosibirsk State Technical University, Novosibirsk, Russia
Keywords: unmanned aerial vehicles, thick airfoil, low Reynolds numbers, flow separation, lift reverse
Abstract
Two wind tunnels were employed for study of a thick teardrop airfoil with the relative thickness of 40 %. Experiments were conducted for Reynolds number in the range from 2 104 to 12 104 and the angle of attack from -10° to +10°. The weight-in-flow measurements and PIV-method visualization were performed. Experiments revealed a strong impact of the free-stream pulsations on the aerodynamic force coefficients. The following phenomena were demonstrated: drag crisis, hysteresis for the lift force vs. angle of attack, and reversing for the lift force direction. Data analysis investigates the roots of these effects.
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