Investigation of Tip vortex on aerodynamic performance of a micro air vehicle

Tip vortex induces downwash movement that reduces the effective angle of attack. When a wing has a relatively low aspect ratio, such as that employed by the micro air vehicle (MAV), the induced drag by the tip vortex is relatively large and therefore the aerodynamic performances of the vehicle are deteriorated. In this paper we study the MAV wing aerodynamics using the endplate to help probe the tip vortex effects. The investigation is facilitated by solving the Navier-Stokes equations around a rigid wing with a root chord Reynolds number of 9×10⁴. It is confirmed that with modest angle of attack, the endplate can reduce the downwash, and therefore increase the effective angle of attack and the lift. However, as the angle of attack becomes higher than 15°, the wing tip vortex is stronger and the endplate can no longer affect the vortex structure to improve lift. Furthermore, drag also increases along with the endplate.