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Abstract：
In this paper, a numerical analysis of a biomimetic unmanned aerial vehicle (UAV) is presented. Its wings feature three grids at the tip similar to the primary feathers of birds in order to modify the lift distribution over the wing and help in reducing the induced drag. Numerical analysis using computational fluid dynamics (CFD) is presented to analyze the aerodynamic effects of the changes in dihedral and angle of attack (with respect of the rest of the wing) of these small grids at the tip. The aerodynamic performances (lift, drag, and efficiency) and rolling capabilities are obtained under different flight conditions. The effects of changing the dihedral are small. However, the change in the grid angle of attack increases aerodynamic efficiency by up to 2.5 times when the UAV is under cruise flight conditions. Changes to the angle of attack of the grids also provide increased capabilities for rolling. Finally, boundary values of the pressure coefficient and non-dimensional velocity contours are presented on the surfaces of the UAV, in order to relate the aerodynamic results to the aerodynamic patterns observed over the wing.
摘要：
在本文中,对仿生无人机(UAV)进行了数值分析。它的机翼在尖端具有三个网格，类似于鸟类的主要羽毛，以修改机翼上的升力分布并有助于减少诱导的阻力。提出了使用计算流体动力学（CFD）的数值分析，以分析尖端这些小网格的二面角和迎角（相对于机翼的其余部分）变化的空气动力学影响。空气动力学性能(升力，拖动,和效率）和滚动能力在不同的飞行条件下获得。改变二面角的影响很小。然而,当无人机处于巡航飞行状态时，网格迎角的变化将气动效率提高了2.5倍。栅格迎角的改变还提供了增加的滚动能力。最后,压力系数和无量纲速度等值线的边界值呈现在无人机的表面上，以便将空气动力学结果与机翼上观察到的空气动力学模式联系起来。
