Turbulent Elementary Votrices and New Development in Theory, Predicition, and control of Turbulence

湍流初等涡流及湍流理论、预测和控制的新进展

基本信息

批准号：
12125101
负责人：
KIDA Shigeo
金额：
$ 4.1万
依托单位：
Kyoto University (2003)National Institute for Fusion Science (2000-2002)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research on Priority Areas
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-12125101/
关键词：
Turbulence Elementary Vortex Turbulence Theory Turbulence Prediction Turbulence Control

项目摘要

The elementary vortices are the smallest coherent structures in turbulence. Their physical characteristics and dynamical roles in turbulence have been clarified by the theory, the experiment, and the computer simulation in various kinds of turbulence realized in nature, laboratories, and computers. The elementary vortices exhibit common physical characteristics independent of the kinds of turbulence, that is, a tubular central vortex is surrounded by spiral vortex layers, the diameter and swirl velocity obey the Kolmogorov scaling laws but the length of the vortex extends to the large scales of turbulence, the vortices make groups and are localized in space, and many elementary vortices tend to approach in an anti-parallel manner and enhance the mixing ability. As engineering and practical applications, the large-eddy-simulation model based on the elementary vortices, the active feedback control of the wall turbulence by manipulating the elementary vortices have been developed, and the mechanisms of the enhancement of supersonic mixing combustion by introducing the longitudinal vortices and the generation of tornados as the large-scale coherent vortex have been clarified. Furthermore, the unstable periodic motions (spatio-temporal coherent structure as the skeleton of turbulence) accompanying regeneration of elementary vortices have been discovered in the Couette turbulence. The concept and the dynamics of turbulent elementary vortices established in the present research project shall be useful for the future turbulence research.

基本涡旋是湍流中最小的相干结构。通过在自然界、实验室和计算机中实现的各种湍流的理论、实验和计算机模拟，阐明了它们的物理特性和在湍流中的动力学作用。基本涡表现出与湍流类型无关的共同物理特征，即管状中心涡被螺旋涡层包围，直径和涡流速度服从柯尔莫哥洛夫标度定律，但涡的长度延伸到大尺度湍流中，涡流成群且局域于空间，许多基本涡流倾向于以反平行方式接近并增强混合能力。在工程和实际应用中，建立了基于基本涡的大涡模拟模型、操纵基本涡的壁面湍流主动反馈控制，以及引入纵向涡流增强超音速混合燃烧的机理。涡旋和龙卷风作为大尺度相干涡旋的产生已经得到澄清。此外，在库埃特湍流中还发现了伴随基本涡再生的不稳定周期运动（时空相干结构作为湍流的骨架）。本研究项目中建立的湍流基本涡的概念和动力学对于未来的湍流研究将是有用的。