Influence of Wing Configurations on Aerodynamic Characteristics of Wings in Ground Effect

Abstract

A numerical analysis is performed to investigate the aerodynamic characteristics and the static height stability of the endplate and the anhedral angle on an aspect-ratio-one wing-in-ground effect. The analysis shows that the ground effect increases the lift by the high pressure on the lower surface, reduces the drag, increases the suction on the upper surface, and considerably enhances the lift-drag ratio. The endplate, which prevents the high-pressure air from escaping out of the lower surface and reduces the influence of the wing-tip vortex, further augments the lift and the lift-drag ratio. Irodov's criteria are also numerically evaluated in order to investigate the static height stability. The comparison of Irodov's criteria shows that the endplate is not favorable for the static height stability. However, the anhedral angle improves the lift as well as Irodov's criteria at various angles of attack and heights. Interestingly, the stagnation point for the anhedral angle moves forward with decreasing height at the low angles of attack and leads an increase in the pressure drag at the leading edge. This increase nullifies the advantages of the induced drag and the pressure drag. Thus, the lift-drag ratio of a wing is not improved as much with an anhedral angle as it is with an endplate.