A Computational Investigation of Bio-Inspired Formation Flight and Ground Effect

Energy saving strategies such as formation flight and near-ground flight are frequently exploited in nature. The energy reduction mechanisms of these approaches are conceptually simple; however, the unsteady wake vortex structures that result from flapping may provide additional benefits. Since these flight strategies offer increased energy savings over simple flight situations, they have received much attention from both the biological sciences and engineering research communities; however, these analysis have traditionally been restricted to the steady aerodynamics of rigid wing vehicles. In this paper, we present a preliminary computational study of energy saving strategies in flapping flight. In both formation flight and ground effect flight, beneficial energy savings are predicted. In the case of formation flight, optimal savings are predicted to occur when the unsteady wake vorticity is exploited by ensuring that the two flappers’ wakes are in spatial phase with wingtips slightly overlapping.