Near wake vortex dynamics of a hovering hawkmoth  

作　　者：Hikaru Aono Wei Shyy Hao Liu 

机构地区：[1]Department of Aerospace Engineering,University of Michigan, Ann Arbor, MI 48109, USA [2]Graduate School of Engineering,Chiba University, Chiba 263-8522, Japan

出　　处：《Acta Mechanica Sinica》2009年第1期23-36,共14页力学学报（英文版）

基　　金：PRESTO (Precursory Research for Embryonic Science and Technology) program of the Japan Science and Technology Agency (JST);Grant-in-Aid for Scientific Research No 18656056 and No 18100002;Japan Society for the promotion of Science (JSPS);a MURI projectunder AFOSR Project No FA9550-07-1-0547

摘　　要：Numerical investigation of vortex dynamics in near wake of a hovering hawkmoth and hovering aerodynamics is conducted to support the development of a biology-inspired dynamic flight simulator for flapping wingbased micro air vehicles. Realistic wing-body morphologies and kinematics are adopted in the numerical simulations. The computed results show 3D mechanisms of vortical flow structures in hawkmoth-like hovering. A horseshoe-shaped primary vortex is observed to wrap around each wing during the early down- and upstroke; the horseshoe-shaped vortex subsequently grows into a doughnut-shaped vortex ring with an intense jet-flow present in its core, forming a downwash. The doughnut-shaped vortex rings of the wing pair eventu- ally break up into two circular vortex rings as they propagate downstream in the wake. The aerodynamic yawing and rolling torques are canceled out due to the symmetric wing kinematics even though the aerodynamic pitching torque shows significant variation with time. On the other hand, the time- varying the aerodynamics pitching torque could make the body a longitudinal oscillation over one flapping cycle.Numerical investigation of vortex dynamics in near wake of a hovering hawkmoth and hovering aerodynamics is conducted to support the development of a biology-inspired dynamic flight simulator for flapping wingbased micro air vehicles. Realistic wing-body morphologies and kinematics are adopted in the numerical simulations. The computed results show 3D mechanisms of vortical flow structures in hawkmoth-like hovering. A horseshoe-shaped primary vortex is observed to wrap around each wing during the early down- and upstroke; the horseshoe-shaped vortex subsequently grows into a doughnut-shaped vortex ring with an intense jet-flow present in its core, forming a downwash. The doughnut-shaped vortex rings of the wing pair eventu- ally break up into two circular vortex rings as they propagate downstream in the wake. The aerodynamic yawing and rolling torques are canceled out due to the symmetric wing kinematics even though the aerodynamic pitching torque shows significant variation with time. On the other hand, the time- varying the aerodynamics pitching torque could make the body a longitudinal oscillation over one flapping cycle.

关 键 词：AERODYNAMICS Hovering Hawkmoth Vortical flow structure 

分 类 号：V211.1[航空宇航科学与技术—航空宇航推进理论与工程]