Dynamics of the perceived velocity gradient tensor and its modelling

doi:10.1103/PhysRevFluids.8.094604

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

	Dynamics of the perceived velocity gradient tensor and its modelling
	Yang PF(杨平凡); Bodenschatz, Eberhard; He GW(何国威); Pumir, Alain; Xu, Haitao
刊名	PHYSICAL REVIEW FLUIDS
	2023-09-25
卷号	8 期号:9 页码:17
ISSN号	2469-990X
DOI	10.1103/PhysRevFluids.8.094604
通讯作者	Pumir, Alain(alain.pumir@ens-lyon.fr)
英文摘要	We study the dynamics of the perceived velocity gradient tensor M constructed from four tracer particles that initially form a regular tetrad of size r0. The exact evolution equation of M, derived in our previous work [Yang et al., J. Fluid Mech. 897, A9 (2020)], contains several unclosed terms. Using numerical data, we compare the exact dynamics of M with the tetrad model [Chertkov et al., Phys. Fluids 11, 2394 (1999)]. In particular, we project the motion onto the (R, Q) plane, where R and Q are the third-and second-order invariants of M. When r0 is in the inertial range of scales of the turbulent cascade, we find that at very short times the tetrad model correctly describes the main features of the dynamics of M on the (R, Q) invariants plane. This suggests that at any instant of time, the unclosed pressure and viscous contributions to the Eulerian dynamics of M could be described by the nonlinear and the damping terms, respectively, in the tetrad model. However, after a time of order similar to 2 tau K, where tau K is the Kolmogorov timescale, the action of the unclosed pressure contribution to the dynamics changes very dramatically to become a strong damping term on the (R, Q) plane. This qualitative change in the dynamics occurs on a timescale that differs from T0, the turnover time at scale r0. In addition, the fluctuations around the mean are found to deviate from the short-correlated-white-noise assumption in the tetrad model, as the timescale of the fluctuation is closer to T0 than tau K.
分类号	二类
资助项目	Natural Science Foundation of China (NSFC) Basic Science Center Program Multiscale Problems in Nonlinear Mechanics[11988102] ; NSFC[12202452] ; NSFC[11672157] ; NSFC[91852104] ; Agence Nationale de la Recherche (ANR) project TILT[ANR-20-CE30-0035]
WOS关键词	NUMERICAL SIMULATIONS ; PRESSURE STATISTICS ; LAGRANGIAN DYNAMICS ; SCALE ; ACCELERATION ; FLUID ; TURBULENCE ; GEOMETRY ; MOTIONS
WOS研究方向	Physics
语种	英语
WOS记录号	WOS:001085024800002
资助机构	Natural Science Foundation of China (NSFC) Basic Science Center Program Multiscale Problems in Nonlinear Mechanics ; NSFC ; Agence Nationale de la Recherche (ANR) project TILT
其他责任者	Pumir, Alain
内容类型	期刊论文
源URL	[http://dspace.imech.ac.cn/handle/311007/93343]
专题	力学研究所_非线性力学国家重点实验室
推荐引用方式 GB/T 7714	Yang PF,Bodenschatz, Eberhard,He GW,et al. Dynamics of the perceived velocity gradient tensor and its modelling[J]. PHYSICAL REVIEW FLUIDS,2023,8(9):17.
APA	杨平凡,Bodenschatz, Eberhard,何国威,Pumir, Alain,&Xu, Haitao.(2023).Dynamics of the perceived velocity gradient tensor and its modelling.PHYSICAL REVIEW FLUIDS,8(9),17.
MLA	杨平凡,et al."Dynamics of the perceived velocity gradient tensor and its modelling".PHYSICAL REVIEW FLUIDS 8.9(2023):17.