The role of velocity derivative skewness in understanding non-equilibrium turbulence  

作　　者：Feng Liu Le Fang Liang Shao 刘锋;方乐;邵亮(School of Energy and Power Engineering,North University of China,Taiyuan 030051,China;Laboratory of Mathematics and Physics,Ecole Centrale de Pékin,Beihang University,Beijing 100191,China;Laboratoire de Mécaniques des Fluides et d’Acoustique,Ecole Centrale de Lyon-Université de Lyon,Ecully 69134,France)

机构地区：[1]School of Energy and Power Engineering,North University of China,Taiyuan 030051,China [2]Laboratory of Mathematics and Physics,Ecole Centrale de Pékin,Beihang University,Beijing 100191,China [3]Laboratoire de Mécaniques des Fluides et d’Acoustique,Ecole Centrale de Lyon-Université de Lyon,Ecully 69134,France

出　　处：《Chinese Physics B》2020年第11期99-105,共7页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(Grant No.11772032);the Science Foundation of North University of China(Grant No.11026829).

摘　　要：The turbulence governed by the Navier-Stokes equation is paramount in many physical processes.However,it has been considered as a challenging problem due to its inherent nonlinearity,non-equilibrium,and complexity.Herein,we review the connections between the velocity derivative skewness Sk and the non-equilibrium properties of turbulence.Sk,a reasonable candidate for describing the non-equilibrium turbulence,which varies during the non-equilibrium procedure.A lot of experimental or numerical evidences have shown that the perturbation of energy spectrum,which associated with the excitation of large scales,results in an obvious variation of Sk,and Sk is a negative value in this rapid energy decay process.The variation of positive Sk is closely related to the perturbation of transfer spectrum,and this corresponds to the backward energy transfer process.In addition,the skewness characterizes the production(or reduction)rate of enstrophy due to vortex stretching(or compression).Using the transport equation of turbulent energy dissipation rate and enstrophy,it is possible to establish a theoretical connection between skewness and the non-equilibrium turbulence.It is expected that this work could trigger the rapid advancement of the future studies of non-equilibrium turbulence,and also the improvement of turbulence models.

关 键 词：velocity derivative skewness non-equilibrium turbulence turbulence model 

分 类 号：O357.5[理学—流体力学]