Insect normal hovering flight in ground effect

Abstract

The ground effect on insect normal hovering is investigated using an immersed boundary-lattice Boltzmann method to solve the two-dimensional incompressible Navier–Stokes equations. A virtual model of an elliptic foil with oscillating translation and rotation near a body surface or ground is used. Computations have been carried out for some parameters including the distance between the foil and the surface, phase difference between the rotation and translation, and amplitude of oscillating rotation. The ground effect on the unsteady forces and vortical structures is analyzed. In particular, three typical regimes of force behavior due to the ground effect, i.e., force enhancement, force reduction, and force recovery regime, are identified and closely associated with the evolution of vortex structures. The results obtained in this study provide physical insight into the understanding of aerodynamics and flow structures for insect normal hovering flight with a ground effect and flying mechanisms relevant to insect perching on body.