Existence of positive skewness of velocity gradient in early transition

doi:10.1103/PhysRevFluids.6.104608

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	Existence of positive skewness of velocity gradient in early transition
	Zhao HK 1; Liu YW1 ; Shao L 2; Fang L3,4 ; Dong M(董明)5
通讯作者	Fang, L.(le.fang@buaa.edu.cn) ; Dong, M.(dongming@imech.ac.cn)
发表期刊	PHYSICAL REVIEW FLUIDS
	2021-10-25
卷号	6 期号:10 页码:21
ISSN	2469-990X
摘要	The present study uses direct numerical simulations to calculate two different transitional flows from laminar flow to turbulence, that is, the two-scale wake flow and the two-dimensional Reyleigh-Taylor unstable flow, respectively. Both results show that the skewness of the longitudinal velocity gradient, Sk, can become positive in the early transition stage, which is beyond our expectation since the turbulent equilibrium state always implies negative values of Sk. These phenomena are explained analytically by considering only two dominant Fourier modes with harmonic relations. It is illustrated that the sign of Sk is not only affected by the amplitudes of the perturbation velocities, but also related to their phases. We expect that the present results will be helpful for understanding the formation of turbulent equilibrium state and for constructing a new measurable criterion of the transition onset.
DOI	10.1103/PhysRevFluids.6.104608
收录类别	SCI ; EI
语种	英语
WOS记录号	WOS:000711843000001
关键词[WOS]	NONEQUILIBRIUM TURBULENT PHENOMENA ; SCHEME
WOS研究方向	Physics
WOS类目	Physics, Fluids & Plasmas
资助项目	National Natural Science Foundation of China[11772032] ; National Natural Science Foundation of China[51976006] ; National Natural Science Foundation of China[U20B2003] ; National Natural Science Foundation of China[11772224]
项目资助者	National Natural Science Foundation of China
论文分区	二类
力学所作者排名	1
RpAuthor	Fang, L. ; Dong, M.
引用统计	被引频次：2[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://dspace.imech.ac.cn/handle/311007/87908
专题	非线性力学国家重点实验室
作者单位	1.Beihang Univ, Sch Energy & Power Engn, Natl Key Lab Sci & Technol Aeroengine Aerothermod, Beijing 100191, Peoples R China; 2.Univ Lyon, Ecole Cent Lyon, CNRS, LMFA, F-69130 Ecully, France; 3.Beihang Univ, Ecole Cent Pekin, Lab Complex Syst, Beijing 100191, Peoples R China; 4.Beihang Hangzhou Innovat Inst Yuhang, Hangzhou 310034, Peoples R China; 5.Chinese Acad Sci, Inst Mech, State Key Lab Nonlinear Mech, Beijing 100190, Peoples R China
推荐引用方式 GB/T 7714	Zhao HK,Liu YW,Shao L,et al. Existence of positive skewness of velocity gradient in early transition[J]. PHYSICAL REVIEW FLUIDS,2021,6,10,:21.
APA	Zhao HK,Liu YW,Shao L,Fang L,&董明.(2021).Existence of positive skewness of velocity gradient in early transition.PHYSICAL REVIEW FLUIDS,6(10),21.
MLA	Zhao HK,et al."Existence of positive skewness of velocity gradient in early transition".PHYSICAL REVIEW FLUIDS 6.10(2021):21.

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