A simple vortex-loop-based model for unsteady rotating wings
A simple vortex-loop-based model for unsteady rotating wings
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DOI：
10.1017/jfm.2019.735
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发表时间：
2019-10
影响因子：
3.7
通讯作者：
Juhi Chowdhury;M. Ringuette
中科院分区：
文献类型：
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作者：
Juhi Chowdhury;M. Ringuette
建立了非定常旋转机翼所产生的升力的解析模型，该构型是扑翼的简单表示。对此进行建模对于仿生无人机的空气动力学和控制系统设计非常重要。这样的努力往往局限于二维的、半经验的、有时计算昂贵的或准稳定的。目前的模型是不稳定的和三维的，但实施起来很简单，只需要机翼运动学和几何学的知识。旋转机翼产生一个由根涡、前缘涡、尖端涡和后缘涡组成的涡环，并随着时间的推移而增长。这被建模为一个倾斜的平面环路，由机翼的大小、方向和运动在几何上指定。通过将涡环的角冲量等同于机翼驱动的流体体积的角冲量，得到了循环升力。势流理论给出了流体惯性升力。将这两个贡献相加，得到总升力公式。该模型与大量实验和计算结果吻合较好。此外，还建立了一个稳态升力模型，与前人在不同攻角下的计算结果进行了比较。
An analytical model is developed for the lift force produced by unsteady rotating wings; this configuration is a simple representation of a flapping wing. Modelling this is important for the aerodynamic and control-system design for bio-inspired drones. Such efforts have often been limited to being two-dimensional, semi-empirical, sometimes computationally expensive, or quasi-steady. The current model is unsteady and three-dimensional, yet simple to implement, requiring knowledge of only the wing kinematics and geometry. Rotating wings produce a vortex loop consisting of the root vortex, leading-edge vortex, tip vortex and trailing-edge vortex, which grows with time. This is modelled as a tilted planar loop, geometrically specified by the wing size, orientation and motion. By equating the angular impulse of the vortex loop to that of the fluid volume driven by the wing, the circulatory lift force is derived. Potential flow theory gives the fluid-inertial lift. Adding these two contributions yields the total lift formula. The model shows good agreement with a range of experimental and computational cases. Also, a steady-state lift model is developed that compares well with previous work for various angles of attack.