Root Cutout Effects on the Aerodynamics of a Low-Aspect-Ratio Revolving Wing

Abstract

Direct numerical simulations of the flow past a low-aspect-ratio revolving wing are performed. The wing undergoes an impulsively started 180 deg revolution about a vertical axis at angles of attack 15, 30, and 45 deg and chord-based Reynolds number 1000. The root cutout is varied at a fixed wing radius, R=4 chords, and the effects on the flow structure and aerodynamic performance of the wing are evaluated. It is shown that an optimum in aerodynamic efficiency exists at low root cutout. Results suggest that this optimum is due to the competition between low Reynolds number effects at the wing root and root vortex effects. In addition, it is shown that a large root cutout can inhibit leading-edge vortex burst that occurs at high angles of attack. However, despite the associated recovery in pressure forces near the wing tip, this inhibition has no significant impact on aerodynamic performance.