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. 2025 May 17;10(5):328.
doi: 10.3390/biomimetics10050328.

Effects of Wing Kinematics on Aerodynamics Performance for a Pigeon-Inspired Flapping Wing

Tao Wu  1 , Kai Wang  2 , Qiang Jia  1 , Jie Ding  2
Affiliations

Effects of Wing Kinematics on Aerodynamics Performance for a Pigeon-Inspired Flapping Wing

Tao Wu et al. Biomimetics (Basel). .

Abstract

The wing kinematics of birds plays a significant role in their excellent unsteady aerodynamic performance. However, most studies investigate the influence of different kinematic parameters of flapping wings on their aerodynamic performance based on simple harmonic motions, which neglect the aerodynamic effects of the real flapping motion. The purpose of this article was to study the effects of wing kinematics on aerodynamic performance for a pigeon-inspired flapping wing. In this article, the dynamic geometric shape of a flapping wing was reconstructed based on data of the pigeon wing profile. The 3D wingbeat kinematics of a flying pigeon was extracted from the motion trajectories of the wingtip and the wrist during cruise flight. Then, we used a hybrid RANS/LES method to study the effects of wing kinematics on the aerodynamic performance and flow patterns of the pigeon-inspired flapping wing. First, we investigated the effects of dynamic spanwise twisting on the lift and thrust performance of the flapping wing. Numerical results show that the twisting motion weakens the leading-edge vortex (LEV) on the upper surface of the wing during the downstroke by reducing the effective angle of attack, thereby significantly reducing the time-averaged lift and power consumption. Then, we further studied the effects of the 3D sweeping motion on the aerodynamic performance of the flapping wing. Backward sweeping reduces the wing area and weakens the LEV on the lower surface of the wing, which increases the lift and reduces the aerodynamic power consumption significantly during the upstroke, leading to a high lift efficiency. These conclusions are significant for improving the aerodynamic performance of bionic flapping-wing micro air vehicles.

Keywords: aerodynamic performance; flapping wing; sweeping motion; twisting motion; unsteady flow.

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Conflict of interest statement

Tao Wu and Qiang Jia are employed by Northwest Institute of Mechanical and Electrical Engineering. Kai Wang and Jie Ding are employed by Norinco Group Air Ammunition Research Institute Co., Ltd. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

Figure 1
Figure 1
Plane shape and sectional profile of a pigeon-inspired flapping wing.
Figure 2
Figure 2
Comparison of the 3D wing model and a real pigeon wing [4].
Figure 3
Figure 3
Movement trajectories of the wingtip and wrist of a pigeon at different flight speeds [25].
Figure 4
Figure 4
Two-joint arm model.
Figure 5
Figure 5
Kinematics of the two-jointed arm model defined by Ψ1, Ψ2, φ1, and φ2.
Figure 6
Figure 6
Side view of trajectories of the wingtip and the wrist of a pigeon wing.
Figure 7
Figure 7
Time histories of Ψ1, Ψ2, φ1, and φ2 fitted using Fourier series.
Figure 8
Figure 8
Grid and simulation results for the NACA0012 pitching case [26,27].
Figure 9
Figure 9
The medium grid. (a) Overset grid. (b) Different views of the flapping wing grid in the partial background grid.
Figure 10
Figure 10
Instantaneous lift coefficient CL and time-averaged lift coefficient CL,mean computed using all the grids.
Figure 11
Figure 11
Instantaneous lift coefficient CL and time-averaged lift coefficient CL,mean computed using different time steps.
Figure 12
Figure 12
The twisting motion of the wingtip under different amplitudes αm.
Figure 13
Figure 13
Effects of αm on CL,mean, CT,mean, Cp,mean, ƞL, and ƞT.
Figure 14
Figure 14
Effects of αm on instantaneous lift coefficient CL.
Figure 15
Figure 15
Flow field vortex structure on the upper surface of a flapping wing under different αm.
Figure 16
Figure 16
Effects of αm on instantaneous power coefficient CP.
Figure 17
Figure 17
Effects of αm on instantaneous thrust coefficient CT.
Figure 18
Figure 18
Pressure distribution at the half-span of the flapping wing under different αm when t = 2.5T.
Figure 19
Figure 19
The motion of the flapping wing with or without sweeping.
Figure 20
Figure 20
Comparison of instantaneous aerodynamic coefficients for the flapping wing with or without the sweeping motion.
Figure 21
Figure 21
Comparison of the upward flapping speed at different spanwise locations of the flapping wing when t = 0.75 T.
Figure 22
Figure 22
Effective incoming velocity ueff and negative effective angle of attack αeff at the tip of the flapping wing when t = 0.75 T.
Figure 23
Figure 23
Flow field vortex structure on the upper surface of the flapping wing when t = 0.75 T.
Figure 24
Figure 24
Flow field vortex structure on the lower surface of the flapping wing when t = 0.75 T.
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