Force Generation Mechanisms by an Insect Wing in Hovering Motion with Different Flipping Schedules

Abstract

The aerodynamic force and the flow structure of a wing performing hovering motion at small Reynolds number (Re=4000) is calculated by computationally solving the 3D Navier-Stokes equations. The computations are performed for the hovering motion which consists of stroke 1, followed by the flipping motion for reversing the direction and then the stroke 2 (similar to stroke 1 but in the opposite direction). The intent of the study is to research the effects of different scheduling of the flip motion between the two strokes. At Re=4000, the delayed stall mechanism is noted during the azimuth rotation of a wing with a high value of CL due to stabilized Leading Edge Vortex. The lift contribution during the flip (pitch rotation for reversing the direction) for the complete stroke is not substantial. During a stroke, the wing encountered the wake from the previous stroke in which, the wake does not contribute positively.

Keywords

• Hovering; Delayed stall; Wake capture; Flip scheduling; Low reynolds number; CFD.