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| 1 | Dynamic flight stability of a hovering model insect:lateral motion显示文摘一只徘回的模型昆虫的侧面的动态飞行稳定性(dronefly ) 用计算液体动力学的方法被学习为解决方程计算稳定性衍生物和特征值和特徵向量分析的技术打手势。主要结果如下。(i) 运动的三个自然模式被识别:一个不稳定的慢分叉模式(模式 1 ) ,一个稳定的慢摆动的模式(模式 2 ) ,和一个马厩快沉淀模式(模式 3 ) 。模式 1 和 2 主要关于水平纵的轴(X 轴) 和一个方面翻译由旋转组成;模式 3 主要关于垂直的轴关于 X 轴和旋转由旋转组成。(ii ) 特征值的近似分析表情被导出,它给物理卓见进运动的自然模式的开始。( iii )为不稳定的分叉模式, t d ,起始的骚乱到的时间两倍,是乘 wingbeat 时期的大约 9 (模型昆虫的纵的运动被显示也不稳定,纵的不稳定的模式的 t d 是乘 wingbeat 时期的大约 14 )。因此,尽管飞行不是动态地稳定的,不稳定性不变得很快,昆虫有足够的时间控制它的翅膀运动压制骚乱。关键词昆虫 - 动态飞行稳定性 - 徘回 - 侧面的运动 - 运动的自然模式工程被中国(10732030 ) 和 111 工程(B07009 ) 的国家自然科学基础支持。 | Yanlai Zhang Mao Sun | 2010 | Acta Mechanica Sinica2010，26，2： | 16 |
| 2 | 蜻蜓非对称扑动时的气动特性显示文摘蜻蜓等昆虫作为飞行领域的佼佼者具有优异的机动性能,然而基于仿生学研制的微型扑翼飞行器在机动性能方面却远不如昆虫。为研究昆虫机动飞行时的气动特性,采用有限体积法(FVM)对蜻蜓左右两侧翅膀非对称扑动时的三维气动力及力矩进行了数值计算,并对不同扑动幅值下蜻蜓的整体气动性能以及每一个翅膀的气动性能、压力分布及流场结构进行了系统分析。结果表明:仅需增加某侧两翅的扑动幅值即可实现向另一侧的机动飞行;相比后翅,扑动幅值对前翅的升推力、滚转及偏航力矩影响较大,而对侧向力的影响较小;扑动幅值对翅膀的瞬时阻力、侧向力、偏航及俯仰力矩在整个扑动周期内均产生了明显影响,而对瞬时升力和滚转力矩的影响则集中在下扑阶段;扑动幅值改变了翅膀前缘涡、尾涡的强度及上下表面的压力差,在下扑阶段,翅膀和蜻蜓对称面有个相对倾角,气动合力产生了较大的侧向力,而上扑阶段,翅膀几乎垂直对称面,产生的侧向力较小。以上结果对于仿生扑翼飞行器的控制及气动设计具有一定指导意义。 | 张锐 周超英 汪超 谢鹏 | 2017 | 航空学报2017，38，12： | 10 |
| 3 | Dynamic flight stability of hovering model insects:theory versus simulation using equations of motion coupled with Navier-Stokes equations显示文摘In the present paper,the longitudinal dynamic flight stability properties of two model insects are predicted by an approximate theory and computed by numerical simulation.The theory is based on the averaged model(which assumes that the frequency of wingbeat is sufficiently higher than that of the body motion,so that the flapping wings' degrees of freedom relative to the body can be dropped and the wings can be replaced by wingbeat-cycle-average forces and moments);the simulation solves the complete equations of motion coupled with the Navier-Stokes equations.Comparison between the theory and the simulation provides a test to the validity of the assumptions in the theory.One of the insects is a model dronefly which has relatively high wingbeat frequency(164 Hz) and the other is a model hawkmoth which has relatively low wingbeat frequency(26 Hz).The results show that the averaged model is valid for the hawkmoth as well as for the dronefly.Since the wingbeat frequency of the hawkmoth is relatively low(the characteristic times of the natural modes of motion of the body divided by wingbeat period are relatively large) compared with many other insects,that the theory based on the averaged model is valid for the hawkmoth means that it could be valid for many insects. | Yan-Lai Zhang Mao Sun | 2010 | Acta Mechanica Sinica2010，26，4： | 9 |
| 4 | Stabilization control of a hovering model insect:lateral motion显示文摘Our previous study shows that the lateral disturbance motion of a model drone fly does not have inherent stability (passive stability),because of the existence of an unstable divergence mode.But drone flies are observed to fly stably.Constantly active control must be applied to stabilize the flight.In this study,we investigate the lateral stabilization control of the model drone fly.The method of computational fluid dynamics is used to compute the lateral control derivatives and the techniques of eigenvalue and eigenvector analysis and modal decomposition are used for solving the equations of motion.Controllability analysis shows that although inherently unstable,the lateral disturbance motion is controllable.By feeding back the state variables (i.e.lateral translation velocity,yaw rate,roll rate and roll angle,which can be measured by the sensory system of the insect) to produce anti-symmetrical changes in stroke amplitude and/or in angle of attack between the left and right wings,the motion can be stabilized,explaining why the drone flies can fly stably even if the flight is passively unstable. | Yan-Lai Zhang Mao Sun | 2011 | Acta Mechanica Sinica2011，27，5： | 1 |
| 5 | 侧风对拍动翅气动力的影响显示文摘昆虫在自然界中飞行时多会受到侧风的干扰,因此了解侧风作用下昆虫拍动翅上气动力的变化对昆虫飞行机理的研究工作具有重要意义。应用计算流体力学(CFD)方法模拟了存在侧风时拍动翅上绕流,并与正常悬停情况进行对比,从侧风的方向和强度2个方面考察了其对拍动翅气动特性的影响。结果表明:侧风对拍动翅气动特性的改变包含2个流动机制的贡献,即相对速度效应和前缘涡轴向速度效应,且从翅尖吹向翅根的侧风与从翅根吹向翅尖的侧风对气动力的影响有着显著的不同;而不同强度的同向侧风下,气动力的改变类似,仅存在数值上的差异。 | 牟晓蕾 许娜 | 2017 | 北京航空航天大学学报2017，43，11： | 0 |
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