An Immersed Boundary Layer Method for 2D Aerodynamic Flapping Mechanisms

Abstract

Our objective is to identify a flapping mechanism which possesses both simple design and optimized aerodynamic efficiency for MAV application. We applied the Immersed Boundary Layer Method for solving the incompressible Navier-Stokes equations around a two dimensional flapping wing. Simple periodic flapping motions along horizontal, inclined and vertical stroke planes that are feasible for MAV application are investigated. For each numerical experiment, the effects of advanced, symmetrical and delayed rotation are distinctly taken into consideration. Estimation of optimized flapping mechanisms is based on sufficient lift coefficient to keep the insect model still in the air and minimum produced power. Considering a particular insect with a given weight, numerical results reveal flapping in horizontal stroke plane with delayed rotation is typical for hovering with minimum power and maximum aerodynamic efficiency. It is also possible for hovering in vertical stroke plane with advanced rotation while hovering along an inclined stroke plane of 60 degrees suggests insufficient lift. A detailed analysis of vorticity field explains the aerodynamic unsteady for lift enhancement.