Numerical Modeling of the Wing Aerodynamics at Angle-of-Attack at Low Reynolds Numbers

Abstract

Flows over symmetrical airfoils are numerically investigated for Reynolds number of 500. The high-resolution vortex method is used for the computations. The effects of both airfoil thickness and angle-of-attack (AoA) on non-linear wake and aerodynamic loads are examined. When increasing AoA from 0∘ to 60∘, a flow regime in the airfoil wake was found to change from stationary to multiperiodic one through the Hopf bifurcation and period-doubling bifurcation. The highest lift-drag ratio of the airfoil is achieved in the stationary regime, when AoA< 15∘. With further increase in the angle-of-attack, the airfoil performance drops due to increment in the drag force. The obtained results show that a thinner airfoil has better hydrodynamic characteristics but the effect of thickness is considerable in the stationary regime only. The analysis of pressure fields shows that negative pressure zones form not only in the airfoil frontal part, as at large Reynolds numbers, but near the trailing edge that is due to effect of boundary layer. The intensity of those grows with increasing an angle-of-attack.