Study on the Aerodynamic Characteristics of Bird-like Flapping Wings Under Multi-degree-of-Freedom Conditions

This study investigates the aerodynamic characteristics of bird-like flapping wings under multi-degree-of-freedom (DOF) motions, using a seagull-inspired wing as the reference model. A three-dimensional flapping-wing geometry was reconstructed based on analytical equations derived from seagull wing measurements. Computational fluid dynamics (CFD) simulations, incorporating dynamic and overlapping mesh techniques, were conducted to capture unsteady aerodynamic behaviors across different DOF configurations. Compared to traditional approaches, the proposed method enables high-fidelity simulation of complex transient effects while maintaining computational efficiency. Results show that the introduction of torsional motion (2 DOF) significantly enhances aerodynamic performance-improving lift and thrust coefficients by increasing pressure differentials and intensifying vortex structures. While increasing flapping frequency leads to higher aerodynamic force generation, greater freestream velocity reduces both lift and thrust. These findings offer improved understanding of avian flight mechanics and highlight the potential for designing more efficient flapping-wing drones and micro aerial vehicles (MAVs). Future research will focus on parameter optimization and application to more complex flight scenarios.