Ground-induced lift enhancement in a tandem of symmetric flapping wings: Lattice Boltzmann-immersed boundary simulations

The behavior of a tandem of symmetric flapping wings immersed in a quiescent viscous fluid is numerically dissected. The attention focuses on the effect on the flight performance of a solid surface which idealizes the presence of the ground. A wide numerical campaign is carried out. The author demonstrates that the presence of a solid surface can drastically modify the lift force, thus giving a remarkable advantage for the vertical take-off. Therefore, a proper governing parameter is proposed, which accounts for the ratio between the initial gap from the solid surface and the length of the wing. (C) 2015 Elsevier Ltd. All rights reserved.