Antisymmetric quadrupole mode of coherent structures in wall-bounded turbulence  

作　　者：Haiping Tian Shaoqiong Yang Lu Cheng Yuan Wang Nan Jiang 

机构地区：[1]Department of Mechanics, Tianjin University [2]Tianjin Key Laboratory of Modern Engineering Mechanics [3]State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, CAS

出　　处：《Theoretical & Applied Mechanics Letters》2013年第5期58-61,共4页力学快报（英文版）

基　　金：supported by the National Natural Science Fundation of China (11272233);National Basic Research Program (973 Program) (2012CB720101);2013 Opening Fund of LNM,Institute of Mechanics,Chinese Academy of Sciences

摘　　要：Abstract Experiments were conducted in a water tunnel by tomographic time-resolved particle image velocimetry （Tomo-TRPIV）. The Reynolds number Reo is 2 460 on the base of momentum thickness. According to the physical mechanism of the stretch and compression of multi-scale vortex structures in the wall-bounded turbulence, the topological characteristics of turbulence statistics in logarithmic layer were illustrated by local-averaged velocity structure function. During coherent structures bursting, results reveal that the topological structures of velocity gradients, velocity strain rates and vorticities behave as antisymmetric quadrupole modes. A three-layer antisymmetric quadrupole vortex packet confirms that there is a tight relationship between the outer layer and the near-wall layer.Abstract Experiments were conducted in a water tunnel by tomographic time-resolved particle image velocimetry （Tomo-TRPIV）. The Reynolds number Reo is 2 460 on the base of momentum thickness. According to the physical mechanism of the stretch and compression of multi-scale vortex structures in the wall-bounded turbulence, the topological characteristics of turbulence statistics in logarithmic layer were illustrated by local-averaged velocity structure function. During coherent structures bursting, results reveal that the topological structures of velocity gradients, velocity strain rates and vorticities behave as antisymmetric quadrupole modes. A three-layer antisymmetric quadrupole vortex packet confirms that there is a tight relationship between the outer layer and the near-wall layer.

关 键 词：wall-bounded turbulence antisymmetric quadrupole mode Tomo-TRPIV vortex packet coherent structure 

分 类 号：O357.5[理学—流体力学] O151.21[理学—力学]