Flow characteristics of aerial swimmers: flapping wing propulsion of tiny insects flying at extremely low Reynolds numbers

空中游泳者的流动特性：极低雷诺数飞行的微小昆虫的扑翼推进

基本信息

批准号：
277483007
负责人：
Professor Dr. Fritz-Olaf Lehmann
金额：
--
依托单位：
Abteilung Tierphysiologie
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2016
资助国家：
德国
起止时间：
2015-12-31 至 2021-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/277483007?language=en
关键词：
Flow characteristics aerial swimmers flapping

项目摘要

Investigating the fluid dynamic processes of force production in complex organisms is central for any in-depth understanding of locomotion in flying and swimming animals. Within the past decade, the unusual and potent mechanisms of lift production in insects and birds have attracted numerous researchers in the field of biological fluid dynamics. Most studies on insect aerodynamics considered animal wings as simple, mostly rigid, flat plates, flapping at high Reynolds numbers between approximately 200 and 10,000. Flight of small insects with wingspans of less than a millimetre, by contrast, had been excluded from this analysis because tiny insects have abandoned altogether airfoil action and literally swim in the air. In contrast to conventional insects and birds, moreover, small insects exhibit unusual wings of comb-like planform, where up to 80% of the wing surface is replaced by long hairs. There is a pronounced gap in our understanding of the aerodynamic consequences of bristle wings for creeping flow propulsion including the question of how drag-based propulsion systems may generate vertical lift for body weight support. This proposal is thus concerned with the fluid dynamic phenomenon in smallest insects flying at Reynolds numbers below approximately 10. We aim to quantify flow structures of bristle wing fliers, scoring wing kinematics by high-speed video technique and quantifying flow structures by time-resolved digital particle image velocimetry (TRPIV). Employing robotic wings, we will determine the functional relevance of bristle wing design on both wake structure and force generation, and subsequently compare flow structures at flapping model wings with the data obtained from the flying insect. The results of this work might give us several new insights into animal locomotion, i.e. by estimating boundary layer structure and viscous drag propulsion in a miniaturized biological flight system and by providing aerodynamic key values for flight that may be used to determine power expenditures and flight efficiency in highly viscous environments.

研究复杂有机体中力产生的流体动态过程对于对飞行和游泳动物的运动的任何深入了解至关重要。在过去的十年中，昆虫和鸟类的升力产量的异常和有效的机制吸引了许多生物流体动力学领域的研究人员。关于昆虫空气动力学的大多数研究都将动物翅膀视为简单的，主要是刚性的平板，在大约200至10,000之间拍打。相比之下，与翼展小于毫米的小昆虫的飞行被排除在这种分析之外，因为微小的昆虫已经完全放弃了机翼动作并在空中游泳。此外，与传统的昆虫和鸟类相反，小昆虫表现出异常的梳状翅膀，其中多达80％的翅膀表面被长毛代替。我们对猪毛机翼在爬行流动推进方面的空气动力学后果的理解中存在明显的差距，包括基于阻力的推进系统如何为体重支撑产生垂直升力的问题。因此，该提案与以下雷诺数量低于10的最小昆虫中的流体动态现象有关。我们旨在量化铜翼翼传单的流量结构，通过高速视频技术对机翼运动学进行评分，并通过时间分辨的数字粒子图像Velocimetry（Trpiv）来量化流动的流动结构。使用机器人翅膀，我们将确定猪翼设计在尾流结构和力产生上的功能相关性，然后将拍打模型机翼的流量结构与从飞行昆虫获得的数据进行比较。这项工作的结果可能会使我们对动物运动有一些新的见解，即通过估算微型生物飞行系统中的边界层结构和粘性阻力推进，并通过为飞行的空气动力学钥匙值提供，该值可用于确定高度粘性环境中的动力支出和飞行效率。