Existence of positive skewness of velocity gradient in early transition

doi:10.1103/PhysRevFluids.6.104608

CORC > 力学研究所 > 中国科学院力学研究所 > 非线性力学国家重点实验室

	Existence of positive skewness of velocity gradient in early transition
	Zhao HK 5; Liu YW 5; Shao L 4; Fang L 2,3; Dong M(董明)1
刊名	PHYSICAL REVIEW FLUIDS
	2021-10-25
卷号	6 期号:10 页码:21
ISSN号	2469-990X
DOI	10.1103/PhysRevFluids.6.104608
通讯作者	Fang, L.(le.fang@buaa.edu.cn) ; Dong, M.(dongming@imech.ac.cn)
英文摘要	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.
分类号	二类
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]
WOS关键词	NONEQUILIBRIUM TURBULENT PHENOMENA ; SCHEME
WOS研究方向	Physics
语种	英语
WOS记录号	WOS:000711843000001
资助机构	National Natural Science Foundation of China
其他责任者	Fang, L. ; Dong, M.
内容类型	期刊论文
源URL	[http://dspace.imech.ac.cn/handle/311007/87907]
专题	力学研究所_非线性力学国家重点实验室
作者单位	1.Chinese Acad Sci, Inst Mech, State Key Lab Nonlinear Mech, Beijing 100190, Peoples R China 2.Beihang Hangzhou Innovat Inst Yuhang, Hangzhou 310034, Peoples R China; 3.Beihang Univ, Ecole Cent Pekin, Lab Complex Syst, Beijing 100191, Peoples R China; 4.Univ Lyon, Ecole Cent Lyon, CNRS, LMFA, F-69130 Ecully, France; 5.Beihang Univ, Sch Energy & Power Engn, Natl Key Lab Sci & Technol Aeroengine Aerothermod, Beijing 100191, 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.