Suction control of flow separation of a low-aspect-ratio wing at a low Reynolds number

Abstract

Suction-based flow control is explored as one of means of enhancing the performance of a low aspect ratio (AR) wing. Large-eddy simulation (LES) was performed to investigate the flow past a three-dimensional (3D) NACA0012 profile wing tip at a chord-based Reynolds number of 35966, such configurations and flow conditions are typical of those utilized in a small unmanned air system (UAS). The flow separation appears at an angle of attack a = 15°, which is used as the example for our investigation. After validating of our numerical results, the suction distribution was designed and mounted near the wing root, and two different control parameters, suction coefficients and angles, were investigated to assess the benefits of flow control and to determine their effectiveness. Our results show that suction control can improve the lift, and the suction coefficient has larger effect on the aerodynamic performances of the wing than that of the suction angle. The lift enhancement is attributed to the standing vortex near the leading edge and the trajectory of wing tip vortex is also affected during the suction control.