This paper investigates the aerodynamics of a wing under figure-of-eight flapping motion based on Fluid–Structure Interaction (FSI) Computational Fluid Dynamics (CFD) simulations. The kinematic of a wing under figure-of-eight motion creates a condition with a variable angle-of-attack. The effect of using different angles of attack at an initial condition, namely initial pitch angles, for the wing and the spatial size of the figure-of-eight pattern, namely the input link angle, is investigated. The initial pitch angles input is varied from 0° to 330° in steps of 30°, and the input link angles used are 30°, 45°, and 60°. The Young’s modulus of the wing is 3.4 GPa spanwise, which is the elastic modulus of balsa wood material. In comparison with an initial pitch angle of 0°, the 90° initial pitch angle shows much better flight performance in terms of lift generated and stability. The results show that the maximum average lift coefficient of 0.393 occurs at the 90° initial pitch angle. The maximum lift-induced moment for the 90° initial pitch angle is only 5.55% of the maximum lift induced moment for the 0° initial pitch angle. A higher input link angle generates a greater lift force. The pressure distribution in the vicinity of the wing area and the von Mises stress of the wing are also presented.

中文翻译：

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八字形扑动下机翼的空气动力学：FSI 模拟

本文基于流体-结构相互作用 (FSI) 计算流体动力学 (CFD) 模拟研究了八字形扑动下机翼的空气动力学。八字形运动下的机翼运动学创造了具有可变迎角的条件。研究了在初始条件下使用不同攻角（即初始俯仰角）对机翼和八字形图案的空间尺寸（即输入连杆角）的影响。初始俯仰角输入从 0° 到 330° 以 30° 为步长变化，使用的输入连杆角度为 30°、45° 和 60°。翼展方向的杨氏模量为 3.4 GPa，为轻木材料的弹性模量。与 0° 的初始俯仰角相比，90°的初始俯仰角在产生的升力和稳定性方面表现出更好的飞行性能。结果表明，最大平均升力系数 0.393 出现在 90° 初始俯仰角处。90° 初始俯仰角的最大升力诱导力矩仅为 0° 初始俯仰角的最大升力诱导力矩的 5.55%。更高的输入连杆角度会产生更大的升力。还给出了机翼区域附近的压力分布和机翼的 von Mises 应力。更高的输入连杆角度会产生更大的升力。还给出了机翼区域附近的压力分布和机翼的 von Mises 应力。更高的输入连杆角度会产生更大的升力。还给出了机翼区域附近的压力分布和机翼的 von Mises 应力。