湍动尺度的模糊聚类分析
Fuzzy Cluster Analysis of Turbulent Scales
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摘要: 湍流运动可看成是大小不同尺度的涡体运动的叠加.定量地确定湍动尺度的分类,对于更好地描述不同尺度的涡体运动,探讨不同尺度涡体之间的相互作用,建立较好的湍流模式都具有重要的意义. 对事物按一定要求进行分类的数学方法,叫做聚类分析.由于湍动尺度的分类具有一定程度的模糊性,因而本文采用模糊聚类的方法,对壁面光滑及租糙两种边界条件下的湍动尺度进行了分类,并对各类结构的特性及其相互作用进行了探讨.Abstract: Turbulent motion could be regarded as the superposition of fluctuations with different scales. It's of great theoretical and practical importance to determine the classification of turbulent scales quantitatively to the better description of vortex motions with different scales, and to the research of the interaction among different sclaes of vortex and the construction of better turbulent models. The mathematical method, which carries out the classification on a certain requirement, is called cluster analysis. In this paper, fuzzy cluster analysis method is used to study the classification of turbulent scales quantitatively in smooth and rough wall boundary conditions. Furthermore, the properties and interactions among all kinds of flow structures are also studied. The results are helpful to gain some insight into the properties and interactions of all kinds of turbulent scales in wall turbulent shear flow.
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[1] Morrison,W.R.B.and R.E.Kronauer,Structural similarity for fully developed trubulence in smooth tubes,J.F.M.,39(1969),117-143. [2] Morrison,W.R.B.,et al.,Experimental evidence of waves in the sublayer,J.F.M.,47(1971),639-656. [3] Lu,S.S.and W.W.Willmarth,Measurements of the structure of the Reynolds stress in a turbulent boundary layer,J.F.M.,60(1973),481-511. [4] Sabot,J.and G.Comte-Bellot,Intermittency of coherent structures in the core region of fully developed turbulent pipe flow,J.F.M.,74(1976),767-796. [5] Wallace,J.M.,et al.,Pattern-recognized structures in bounded turbulent shear flows,J.F.M.,83(1977),673-693. [6] Blackwelder,R.F.and R.E.Kaplan,On the wall structure of the turbulent boundary layer,J.F.M.,76(1976),89-112. [7] Chen,Chyan-Hai P.and R.F.Blackwelder,Large-scale motion in a turbulent boundary layer:a study using temperature contamination,J.F.M.,89(1978),1-31. [8] Ueda,H.and J.O.Hinze,Fine-structure turbulence in the wall region of a turbulent boundary layer,J.F.M.,67(1975),125-143. [9] 梁在潮,《紊流力学》,河南科技出版社 (1988). [10] 汪培庄,《模糊集合论及其应用》,上海科技出版社(1983). [11] 刘士和,复杂边界湍流相干结构及其理论探讨,武汉水利电力学院博士论文(1987).
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