Aerodynamics of unconventional airfoils

Abstract

This project will explore lift enhancement methods for MAVs under low Reynolds number flight where CLmax are significantly lower. It will study the beneficial effects of vortices to enhance lift through both Static and Dynamic Leading Edge Vortices (LEVs). LEVs create an area of suction which generates a low pressure region to increase lift.

Static LEVs are stationary vortices trapped over the top surface of an airfoil. As such, it will be shown here that static LEVs can be created and trapped through the use of cavities. This project will assess the effectiveness of different cavity airfoil designs in vortex capturing and from one of them, analyze the amount of additional lift created. As it will be showed both experimentally and computationally, the lift characteristics of cavity airfoils are lower than that of non-cavity airfoils.

Dynamic LEVs are created through flapping motion and are most prominent at the end of its up-stroke. It forms over the leading edge and is shed downstream towards the trailing edge. In this project, it will first study the lift characteristics of static flat plate in low Reynolds number flow where there is absence of Dynamic LEVs. Subsequently, a flapping flat plate will be used to create Dynamic LEVs at the end of its up-stroke and average lift coefficients measured. It will be shown experimentally that the results from flapping flat plate (after modification) was creating higher lift as compared to static flat plate.