Aperture Effect of Normal Hovering Flight in Close Proximity to the Ground

Abstract

Aerodynamics of a flapping foil at low Reynolds number in close proximity to the ground in aperture effect are studied by numerical simulations based on the normal hovering motion mode. A vortex street is interestingly generated by both ground and aperture effects and the rotation of the foil. The study reveals that the aperture takes a force-reduction effect and a large enough aperture effectively can remove the ground force-enhancement effect produced when the foil is in close proximity to the ground. This paper provides an effective method of optimizing foil-flapping flight design of flying robotics over a porous plane. Keywords: aerodynamics; flapping foil; low Reynolds number; ground effect; aperture effect