Effects of streamwise rotation on helicity and vortex in channel turbulence

doi:10.1017/jfm.2024.37

	Effects of streamwise rotation on helicity and vortex in channel turbulence
	Hu, Running 1,2; Li, Xinliang1,2 ; Yu, Changping1
通讯作者	Yu, Changping(cpyu@imech.ac.cn)
发表期刊	JOURNAL OF FLUID MECHANICS
	2024-02-08
卷号	980 页码:30
ISSN	0022-1120
摘要	Helicity plays a key role in the evolution of vortex structures and turbulent dynamics. The helicity dynamics and vortex structures in streamwise-rotating channel turbulence are discussed in this paper using the helicity budget equation and the differentiated second-order structure function equation of helicity. Generally, rotation and Reynolds numbers exhibit opposing effects on the interscale helicity dynamics and the vortices. Under the buffer layer, the positions of the helicity peaks are proportional to the ratio between the Reynolds and rotation numbers. The mechanism is related to the opposing effects of convection and rotation. Rotation directly affects the helicity balance through the Coriolis term and corresponding pressure term. In the buffer layer, the scale helicity is negative at small scales but positive at large scales, which is mainly induced by the spatial effects (the production and the spatial turbulent convection) but reduced by interscale cascades. Examination of structures reveals the close association between scale helicity and streaks, with streak lift angles exhibiting an increase with rotation and a decrease with Reynolds numbers. In the log-law layer, the Coriolis terms and corresponding pressure terms are proportional to the rotation numbers but remain independent of the Reynolds numbers. The negative scale helicity is forward cascaded towards small scales. Generally, spanwise vortices in the log-law layer are related to sweep events and forward cascades. Our findings indicate that these spanwise vortices are suppressed by rotation but recover with increasing Reynolds numbers, aligning with the effects observed in the scale helicity balance.
关键词	rotating turbulence channel flow turbulence simulation
DOI	10.1017/jfm.2024.37
收录类别	SCI
语种	英语
WOS记录号	WOS:001157327300001
关键词[WOS]	DIRECT NUMERICAL-SIMULATION ; FLOW ; ENERGY ; GENERATION ; DYNAMICS ; CASCADE
WOS研究方向	Mechanics ; Physics
WOS类目	Mechanics ; Physics, Fluids & Plasmas
资助项目	National Key Research and Development Program of China[2020YFA0711800] ; National Key Research and Development Program of China[2019YFA0405300] ; NSFC[12072349] ; NSFC[12232018] ; NSFC[91852203] ; NSFC[12202457]
项目资助者	National Key Research and Development Program of China ; NSFC
引用统计
文献类型	期刊论文
条目标识符	http://dspace.imech.ac.cn/handle/311007/94437
专题	高温气体动力学国家重点实验室
通讯作者	Yu, Changping
作者单位	1.Chinese Acad Sci, Inst Mech, LHD, Beijing 100190, Peoples R China 2.Univ Chinese Acad Sci, Sch Engn Sci, Beijing 100049, Peoples R China
推荐引用方式 GB/T 7714	Hu, Running,Li, Xinliang,Yu, Changping. Effects of streamwise rotation on helicity and vortex in channel turbulence[J]. JOURNAL OF FLUID MECHANICS,2024,980:30.
APA	Hu, Running,Li, Xinliang,&Yu, Changping.(2024).Effects of streamwise rotation on helicity and vortex in channel turbulence.JOURNAL OF FLUID MECHANICS,980,30.
MLA	Hu, Running,et al."Effects of streamwise rotation on helicity and vortex in channel turbulence".JOURNAL OF FLUID MECHANICS 980(2024):30.