A research paper by scientists at Beijing Institute of Technology presented a CFD simulation method based on biological experimental data to analyze the aerodynamic performance of pigeons during takeoff, leveling flight, and landing in free flight.
The research paper, published on Mar. 11, 2025 in the journal Cyborg and Bionic Systems.
Birds achieve remarkable maneuverability in takeoff, steady flight, and landing by continuously and adaptively morphing their wing shape, yet existing bio-inspired flapping-wing aerial vehicles still struggle to replicate these capabilities. Prior research has often simplified avian wing kinematics to isolated flapping, twisting, or folding motions or relied on static scanning and wind-tunnel models, failing to capture the true coupled deformations of freely flying birds. "Moreover, three-dimensional reconstructions of medium-sized birds like pigeons have been limited by experimental space, occlusion of key joint positions, and constrained degrees of freedom, leaving the full cycle of natural wing morphing poorly understood." said the author Yishi Shen, a researcher at Beijing Institute of Technology, "Consequently, there is an urgent need for experimental measurements of real pigeon wing motion in free flight to build a true three-dimensional coupled wing model and employ computational fluid dynamics to uncover the aerodynamic mechanisms underlying different flight stages."
In this paper, authors propose a CFD simulation method based on biological experimental data to analyze the aerodynamic performance of pigeons during takeoff, leveling flight, and landing in free flight. Firstly, authors used 30 motion capture cameras in a 16 m × 5 m × 3 m space to collect the wing movement data of pigeons throughout the entire free flight process. Secondly, authors decoupled and analyzed the complex coupled wing movements into 5 kinematic parameters: flapping, twisting, sweeping, folding, and bending. A wing model was constructed to conduct aerodynamic simulations by simplifying the scanned wing surface profiles. The wing's movements were defined using rotation matrices employed in the simulation process. To better understand the aerodynamic mechanisms of the wings during 3 different stages, authors used CFD methods to analyze the aerodynamic characteristics of the coupled movements of the 5 kinematic parameters. Furthermore, authors provided a detailed analysis of the flow field structures during each process.
This study found that, within a wingbeat cycle, pigeons during the takeoff stage cause the leading-edge vortex to attach earlier, enhancing instantaneous lift to overcome gravity and achieve ascending. During the leveling flight stage, the pigeon's average lift becomes stable, ensuring a steady flight posture. In the landing stage, the pigeon increases the wing area facing the airflow to maintain a stable landing posture, achieving a more minor, consistent average lift while increasing drag. "Our study enhances our understanding of birds' flight mechanisms and provides theoretical guidance for developing efficient bio-inspired flapping-wing aerial vehicles." said Yishi Shen.
Authors of the paper include Yishi Shen, Yi Xu, Weimin Huang, Chengrui Shang, and Qing Shi.
This work was supported in part by the National Natural Science Foundation of China under grants 61933001, U2013208, and 62088101.
The paper, "Effect of Coupled Wing Motion on the Aerodynamic Performance during Different Flight Stages of Pigeon" was published in the journal Cyborg and Bionic Systems on Mar. 11, 2025, at DOI: 10.34133/cbsystems.0200.
