Near wake vortex dynamics of a hovering hawkmoth

• 来源期刊: 力学学报(英文版)
• 年，卷（期）: 2009,（1）
• 页码范围: 23-36
• 页数: 14页
• 语种: 英文
• DOI: 10.1007/s10409-008-0210-x

摘要

Numerical investigation of vortex dynamics in near wake of a hovering hawkmoth and hovering aerody-namics is conducted to support the development of a biology-inspired dynamic flight simulator for flapping wing-based 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 roll-ing torques are canceled out due to the symmetric wing kine-matics 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.