多段翼多自由度扑翼飞行器气动特性仿真研究

Simulation Study on Aerodynamic Characteristics of Flapping-wing Aircraft with Multi-stage Wing and Multiple Degree of Freedom

传统扑翼飞行器模型中机翼多数是二维刚性翼,且上扑、下扑过程完全对称。为进一步改良扑翼机气动特性,利用近似柔性思想,建立多段式机翼,达到近似柔性效果,加入急回特性,延长了下扑时间;并在原有扑动、扭转两个运动的基础上加入弯曲折叠运动,提出了一种“扑动-扭转-弯曲折叠”三维模型;将建立的模型导入Xflow,改变扑翼机模型的运动参数,对扑翼飞行器模型进行气动仿真,得出了多段翼多自由度扑翼飞行器升力系数、推力系数与来流速度、扑动频率、机翼初始迎角、内翼扑动幅值之间的非线性关系。

In the traditonal flapping-wing aircraft model, most of the wings are two-dimensional rigid wings, and the upswing and downwing processes are completely symmetrical. In order to further improve the aerodynamic characteristics of the flapping-wing aircraft, this paper uses the idea of approximate flexibility to establish the multi-stage wing to achieve the approximate flexibility effect. At the same time, the rapid return characteristic is added to prolong the down-flapping time. And a three-dimensional model of “flutter-twist-bend folding” is proposed by adding the bending-folding motion on the basis of the original movement and twisting motion. The model is imported into Xflow to change the motion parameters of the flapping-wing aircraft model, and the aerodynamic simulation of the flapping-wing aircraft model is carried out. Therefore, the non-linear relationship between the lift coefficient and the trust coefficient of the multi-stage wing and the MDOF (multiple degree of freedom) of the flapping-wing aircraft and the flow velocity, the flapping frequency, the wing initial angle of attack and the inner wing flutter amplitude is obtained.