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为了解鸟类翅膀折叠运动的作用,对一个专利中的折叠扑翼机构进行了数学建模,外翼的折叠运动由非定常过程中的气动力、弹性恢复力矩和惯性力决定。利用风洞试验和数值模拟两种方式对该折叠扑翼模型进行了研究。数值模拟和风洞试验结果表明:相对于非折叠扑翼,折叠翼能够有效提高平均升力;在一定范围内增加内翼扑动频率可以提高折叠翼平均升力系数,但对折叠翼平均阻力系数影响甚微;一个扑动周期内折叠翼能量耗损小于非折叠翼;各力系数曲线揭示了折叠翼与非折叠翼气动特性差别的原因。所以,在扑翼飞行器设计时采用折叠运动是有利的。
In order to understand the effect of bird wing folding movement, the folding flapping wing mechanism of a patent is mathematically modeled. The folding movement of the wing is determined by the aerodynamic forces, elastic restoring moments and inertial forces in unsteady processes. The folding flapping wing model was studied by wind tunnel test and numerical simulation. Numerical simulation and wind tunnel test results show that, compared with non-folding flapping wing, the folding wing can effectively increase the average lifting force; increasing the inner wing flapping frequency within a certain range can increase the average lifting coefficient of the folding wing but affect the average drag coefficient of the folding wing The flutter cycle energy loss of folding wing is less than that of non-folding wing. The curve of each force coefficient reveals the difference of aerodynamic characteristics of folding wing and non-folding wing. Therefore, it is advantageous to employ folding motion in the design of flapping-wing aircraft.