The Drag of an Elliptical Airfoil at a Reynolds Number of 1000

Abstract

There have been many studies on the mechanisms of unsteady aerodynamics, such as leading-edge vortex (LEV) formation, wing-wake interaction, and spanwise flow. Spanwise flow can only be observed on three-dimensional wing models; however other phenomena such as LEV and wing-wake interaction can be captured using two-dimensional airfoil models. This study focuses on two-dimensional elliptical airfoil because this profile can generate counter-rotating vortices used by insects to generate aerodynamic forces. This research aims to analyze the drag production of two-dimensional elliptical airfoils flapping with bumblebee-inspired kinematics in asymmetrical normal-hovering mode at a typical Reynolds number range of . It is found that drag is generated during the downstroke while thrust during the upstroke. It is also found that the creation and shedding of counter-rotating vortices are closely related to the generation of thrust. The results also indicate that asymmetrical strokes can be used in normal hovering to minimize drag or produce thrust.