Influence of surface flow on aerodynamic loads of a cantilever wing

Abstract

The properties of the characteristic surface flow modes and their influence on the aerodynamic loads of a cantilever wing at low chord Reynolds numbers were experimentally studied. The chordwise variations of the separation and reattachment locations as well as the length and center position of the separation bubble in the domain of the chord Reynolds number/root angle of attack heavily depend on the characteristic surface flow modes. The aerodynamic loads, e.g., the lift, drag, and moment coefficients, are profoundly influenced by the characteristic behaviors of suction surface flow. The lift coefficient increases with the increase of root angle of attack in the regimes of laminar separation, separation bubble, and transition. The curve of lift coefficient has a largest slope in the laminar separation regime. The increase rate of the lift coefficient decreases when the separation bubble is formed. The stall happens in the turbulent separation regime. The drag coefficient slightly decreases in the laminar separation regime, remains almost a constant in the separation bubble regime, and increases in the transition regime.