Study on High Lift and Thrust Mechanisms of Unsteady Airfoil and Its Effective Application

非定常翼型高升力推力机构研究及其有效应用

• 批准号: 15360098
• 负责人: TANAKA Kazuhiro
• 金额: $ 9.73万
• 依托单位: Kyusyu Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-15360098/
• 关键词: Unsteady flow; Separation; Airfoil; Pitching motion; Heaving motion; Vortex; Lift; Thrust; 非定常運動; Unsteady flow (非定常流れ); Separation (はく離); Airfoil (翼); Piching motion (ピッチング運動); Heaving motion (ヒービング運動); Vortex (渦); Lift (揚力); Thrust (推進力)

It is well known that a flow field around a moving airfoil, which is a typical unsteady flow, is extremely complicated since there are a number of parameters and dynamic behaviors of vortices that characterize such a flow. A number of studies on unsteady flow around a moving airfoil have been carried out with numerical and experimental approaches. Most of them, however, focused high Reynolds number regions over Re=10^6. Recently, a few studies on unsteady flows in low Reynolds number regions have been attracting attentions since the Micro-Electro-Mechanical-Systems has been improved with the aim of flow control and development of Micro-Air-Vehicle and micro flight robot. This flow field has also attracted significant attentions in biohydrodynamics as there is a high need to understand the propulsion mechanisms of aquatic animals, birds and insects. However, the detailed vortex flow structure behind moving airfoils and the relationship between the characteristics of dynamic forces actin … More g on them and the vortex flow structure at low Reynolds number region have not been clarified sufficiently.In this study, the authors have measured the detailed vortex flow behind a pitching airfoil and a heaving airfoil, at low Reynolds number region by PIV measurement. Moreover, the authors have performed dynamic thrust measurement acting on them by a six-axes sensor in a water tunnel. The result clarified not only the detailed vortex structure, such as vortex flow pattern, vorticity distribution and jet characteristics, but also the relationship between the characteristics of dynamic thrust and detailed vortex flow structure.The re-circulation region was formed by a few discrete vortices. The scale of discrete vortex shed from the leading edge was about one fourth of the chord length and it did not depend on the airfoil configuration. The length of the re-circulation region to the chord length determined the number of discrete vortex consisting there. The dynamic behavior of discrete vortex depended on the airfoil configuration, however the vortex shedding frequency of the discrete vortices did not depend on the airfoil configuration. Moreover, the dynamic behavior of discrete vortex influenced much on the dynamic lift.At the high non-dimensional trailing edge velocity and the non-dimensional heaving velocity, the thrust producing vortex street is formed clearly. Moreover, it has been founded that not only the distance between vortices becomes narrow but also vorticity increases as the non-dimensional trailing edge velocity and the non-dimensional heaving velocity increase. As a result, the jet velocity induced by the strong vorticity turns out to be high.The averaged dynamic thrust acting on a pitching airfoil and a heaving airfoil increases as the non-dimensional trailing edge velocity and the non-dimensional heaving velocity increase. The hysteresis loops of dynamic thrust acting on a pitching airfoil and a heaving airfoil show reentrant and convexity shapes characteristics. The dynamic behavior of dynamic thrust acting on a heaving airfoil is different from that on a pitching airfoil.The thrust efficiency of a pitching airfoil increased up to V_p=0.7 rapidly and maximum thrust efficiency was 0.34. The thrust efficiency of a heaving airfoil increased up to V_p=0.5 rapidly and the maximum thrust efficiency was 0.20. In both airfoils, the thrust efficiency decreases with increase of the non-dimensional velocity because not only thrust but also moment acting on a pitching airfoil and lift acting on a heaving airfoil increases rapidly. Less

众所周知，移动的机翼周围的流场是典型的不稳定流，非常复杂，因为有许多参数和涡流的动态行为表征了这种流动。已经采用数值和实验方法进行了许多关于移动机翼周围不稳定流动的研究。但是，其中大多数集中在RE = 10^6上方的高雷诺数区域。最近，自微电动机械系统以来，对低雷诺数区域中不稳定流动的一些研究引起了人们的关注，目的是为了流动控制和微型空气车辆和微型飞行机器人的发展。由于了解水生动物，鸟类和昆虫的推进机理的需求很高，因此该流场也引起了生物水力动力学的极大关注。然而，尚未正确阐明移动机翼的详细涡流流结构以及动态力肌动蛋白的特征……更多的G和低雷诺数区域的涡流流量结构。在这项研究中，作者测量了在俯仰机翼和低reynolds Norkity potur airfier airfiers air fia -Reynolds Norke的详细涡流中的详细涡流流。此外，作者已经通过水隧道中的六轴传感器对它们进行了动态推力测量。结果不仅阐明了详细的涡旋结构，例如涡流流模式，涡旋分布和喷射特性，而且还阐明了动态推力的特征与详细的涡旋流量结构之间的关系。再循环区域由一些离散的涡流形成。从前缘脱离的离散涡流的比例约为和弦长度的四分之一，它不取决于翼型的配置。重新循环区域到和弦长度的长度确定了那里的离散涡流的数量。离散涡流的动态行为取决于翼型配置，但是离散涡流的涡流脱落频率并不取决于机翼配置。此外，离散涡流的动态行为对动态升力产生了很大的影响。在高的非尺寸后尾边缘速度和非二维加热速度下，明显形成了推力产生的涡旋街。此外，已经建立的是，不仅涡旋之间的距离变得狭窄，而且随着非二维后缘边缘速度和非二维加热速度的增加，涡度也会增加。结果，强涡度引起的射流速度被证明很高。平均动态推力作用在俯仰机翼上，并且随着非尺寸的尾随边缘速度和非少量加热速度的增加，重型机翼增加。动态推力作用在俯仰机翼上的动态推力和重型机翼的磁滞循环显示出重点和凸的形状特征。作用在加热机翼上的动态推力的动态行为与在俯仰机翼上的动态行为不同。俯仰机翼的推力效率提高到v_p = 0.7迅速，最大推力效率为0.34。重型机翼的推力效率迅速提高至V_P = 0.5，最大推力效率为0.20。在这两种机翼中，推力效率随着非二维速度的增加而降低，因为不仅推力，而且动力在俯仰机翼上作用，并在重型机翼上作用迅速增加。较少的

项目成果

非定常運動翼後流の渦構造

不稳定动叶片后面的涡结构

• 发表时间: 2004
• 期刊: 第32回可視化情報シンポジウム講演論文集 Vol.24,No.1
• 作者: 渕脇正樹;田中和博
• 通讯作者: 田中和博

Vortex structure behind unsteady airfoils

非定常翼型背后的涡结构

• 发表时间: 2004
• 期刊: Proceedings of Journal of The Visualization Society of Japan (ISSN 0916-4731) Vol.24,No.1
• 作者: Masaki Fuchiwaki;Kazuhiro Tanaka
• 通讯作者: Kazuhiro Tanaka

Masaki Fuchiwaki, Chang Jo Yang, Kazuhiro Tanaka: "Unsteady Separation and Vortex around Moving Airfoil"4th JSME/ASME Joint Fluids Engineering Division Annual Summer Meeting, FEDSM 03-45192. (CD-ROM). (2003)

Masaki Fuchiwaki、Chang Jo Yang、Kazuhiro Tanaka：“移动机翼周围的不稳定分离和涡流”第四届 JSME/ASME 联合流体工程部年度夏季会议，FEDSM 03-45192。

Vortex Structure and Scale on an Unteady Airfoil

不稳定翼型上的涡结构和规模

• 发表时间: 2005
• 期刊: Proceedings of Internatilnao Conference on Jets, Wakes and Separated Flows, JSME No. 05-201
• 作者: Masaki Fuchiwaki;Kazuhiro Tanak
• 通讯作者: Kazuhiro Tanak

Masaki Fuchiwaki, Chang Jo Yang, Kazuhiro Tanaka: "Detailed Visualization of Re-circulation Region on Unsteady Airfoils"The 7th Asian Symposium on Visualization,1A-1. (CD-ROM). (2003)

Masaki Fuchiwaki、Chang Jo Yang、Kazuhiro Tanaka：“不稳定翼型再循环区域的详细可视化”第七届亚洲可视化研讨会，1A-1。