Study of Aerodynamic Characteristics of Self-propelled Airfoils with Tandem Configuration

Abstract

The tandem configuration of flapping wings is widely found in nature. To explore the benefits of this arrangement on the aerodynamic characteristics of flapping wings, in this paper, the aerodynamic characteristics of tandemly arranged non-zero-angle-of-attack self-propelled flapping wings are investigated by employing the immersed boundary-lattice Boltzmann method. Two parameters: the inter-spacing of the two airfoils d and the flapping phase difference φ, are concerned. The results show that the average lift coefficient and the average lift efficiency are high when the spacing is smaller or larger (d ≤ 1.0 and d ≥ 3.0), but the propulsion efficiency of those is low. The average lift coefficient is high when the phase difference is smaller or larger (φ ≤ 0.25 and φ ≥ 0.625). The tandem airfoil with close to anti-phase flapping has better efficiency of propulsion and lift generation. These results can provide guidance for the design of flapping wing micro air vehicles with a tandem arrangement.