Identification and clarification of the spiral vortex structure in the turbulent boundary layer on a rotating cylinder

旋转圆柱体湍流边界层螺旋涡结构的识别和澄清

• 批准号: 17560141
• 负责人: YAMASHITA Shintaro
• 金额: $ 2.24万
• 依托单位: Gifu University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2005
• 资助国家: 日本
• 起止时间: 2005 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-17560141/
• 关键词: Three-dimensional turbulent flow; Rotating cylinder; Coherent structure; Boundary layer; Spiral vorted; Proper orthogonal decomposition; Intermittency factor; Spectrum; 動的組織構造; VITA法; 四象限分割法

The objective of the present study is to investigate experimentally the coherent structure of the turbulent boundary layer, which has skewed velocity profiles, on a rotating cylinder in an axial flow, and, in particular, to identify and clarify the spiral vortex structure in this boundary layer. This flow is one of the basic models of three-dimensional turbulent wall flows, which should be treated as the complex turbulent flows affected by body forces and extra rates of strain.For a stationary cylinder, the bursting phenomena and the turbulent coherent structure were investigated using VITA technique and four-quadrant method from the instantaneous time-series data obtained. Any critical differences in these quantities from the flat-plate turbulent boundary layer were not found.In order to investigate the spiral vortex structure, a measuring system utilizing hot-wire rake was constructed, and firstly an attempt was made to extract the coherent structure of the flat-plate boundary layer. … More The analysis of proper orthogonal decomposition as one of the tool to extract the coherent structure was undertaken for the multi-point instantaneous time-series data. The result showed that the eigenfunction of the second mode as well as the first mode was crucial to identify the coherent structure. The turbulent and non-turbulent character in outer region of the turbulent boundary layer that is one of the structures of the outer layer was discerned by using the first and the second modes.Skewed mean velocity profiles and fluctuating velocity distribution in case of rotating cylinder were measured using the hot-wire anemometry, and the validity of several laws of the universal velocity distribution proposed so far with respect to the measured mean velocity profiles were examined.An attempt was made by using the flatness factor and intermittency factor to inquire the coherent structure in the outer region, but it was difficult to capture any structure proper to the rotating cylinder with these parameters. Then the power spectra of the fluctuating velocities were investigated. Each of the power spectra for the rotating cylinder exhibited a bump in the middle frequency range, whereas for the stationary cylinder as well as for the flat plate they decreased monotonically with increase in the frequency, and the bump frequency became higher as the rotation speed increased. This fact showed clearly that the coherent structure of the turbulent boundary layer on a rotating cylinder was fairly regular enough to reveal itself in the spectrum, and it was suggested that there existed a spiral vortex structure enwinding the cylinder. Less

本研究的目的是通过实验研究湍流边界层的相干结构，该结构在轴向流中的旋转缸上偏向速度曲线，尤其是在该边界层中识别和识别和阐明螺旋涡流结构。该流程是三维湍流壁流的基本模型之一，应将其视为受体力影响的复杂湍流和额外的应变速率。对于固定的圆柱体，使用Vita技术和四季度的方法获得了即时的时间序列数据获得的固定圆柱，爆发现象和湍流相干结构。从平板湍流边界层中找不到这些数量的任何关键差异。为了研究螺旋涡流结构，构建了使用热线耙的测量系统，首先试图提取平板边界层的相干结构。 ...更多地分析适当的正交分解作为提取相干结构的工具之一，用于多点瞬时时间序列数据。结果表明，第二模式和第一种模式的征函数对于识别相干结构至关重要。湍流边界层外部区域的湍流和非扰动特征是通过使用第一种和第二个模式来识别外层结构之一。使用第一个模式和第二个模式，使用热量触发器的均值衡量的均值，对旋转圆柱的旋转圆柱测量的平均速度曲线和波动的速度分布进行了测量。通过使用平坦度因子和间歇性因子来查询外部区域的相干结构，但很难用这些参数捕获适当的旋转圆柱体的任何结构。然后研究了波动速度的功率光谱。旋转缸的每个功率光谱都在中间频率范围内暴露了一个凸起，而对于固定缸以及平板，随着频率的增加，它们单调降低，并且随着旋转速度的增加，凸起频率变得更高。这一事实清楚地表明，旋转圆柱体上湍流边界层的一致结构足够规律，可以在光谱中露出来，并且建议存在伴随圆柱体的螺旋涡流结构。较少的

项目成果

超音波速度分布計を用いた円柱後流の放出渦度測定

使用超声波速度分布计测量圆柱尾流的脱落涡度

• 发表时间: 2005
• 期刊: 日本機械学会2005年度年次大会講演論文集 Vol.2
• 作者: Y.Inoue;H.Yano;S.Yamashita;井上 吉弘;山下 新太郎;井上 吉弘;Yoshihiro INOUE;Yoshihiro INOUE;井上 吉弘
• 通讯作者: 井上 吉弘

Experimental Study on a Three-Dimensional Wall Jet (Flow Field in a Cross-Section of Developed Region)

三维壁射流实验研究（发达区域断面流场）

• 发表时间: 2006
• 期刊: Transactions of JSME (in Japanese) Vol.72, No.724
• 作者: Y.Inoue;H.Yano;S.Yamashita
• 通讯作者: S.Yamashita

Visualization of Large-Scale Flow Structures in a Three-Dimensional Wall Jet

三维壁射流中大规模流动结构的可视化

• 发表时间: 2006
• 期刊: Journal of the Visualization Society of Japan (in Japanese) Vol.26 Suppl., No.2
• 作者: Y.Inoue;H.Yano;S.Yamashita
• 通讯作者: S.Yamashita

形状の異なるノズルから噴出させられた噴流の近傍構造に関する実験

不同形状喷嘴射流附近结构实验

• 发表时间: 2006
• 期刊: 日本機械学会流休工学部門講演会講演論文集 No. 1701(CD-ROM)
• 作者: 張 丹;鬼頭修己;牛島達夫;井上 吉弘;山下 新太郎;井上 吉弘;井上 吉弘
• 通讯作者: 井上 吉弘

A Comparative Study on the Coherent Structures in 2D and 3D Wall Jets

2D 和 3D 壁射流相干结构的比较研究

• 发表时间: 2005
• 期刊: Proceedings of International Conference on Jets, Wakes and Separated Flows, Toba, Japan
• 作者: Y.Inoue;H.Yano;S.Yamashita;井上 吉弘;山下 新太郎;井上 吉弘;Yoshihiro INOUE
• 通讯作者: Yoshihiro INOUE