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 | |
通讯作者 | Pumir, Alain(alain.pumir@ens-lyon.fr) |
发表期刊 | PHYSICAL REVIEW FLUIDS |
2023-09-25 | |
卷号 | 8期号:9页码:17 |
ISSN | 2469-990X |
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. |
DOI | 10.1103/PhysRevFluids.8.094604 |
收录类别 | SCI ; EI |
语种 | 英语 |
WOS记录号 | WOS:001085024800002 |
关键词[WOS] | NUMERICAL SIMULATIONS ; PRESSURE STATISTICS ; LAGRANGIAN DYNAMICS ; SCALE ; ACCELERATION ; FLUID ; TURBULENCE ; GEOMETRY ; MOTIONS |
WOS研究方向 | Physics |
WOS类目 | Physics, Fluids & Plasmas |
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] |
项目资助者 | Natural Science Foundation of China (NSFC) Basic Science Center Program Multiscale Problems in Nonlinear Mechanics ; NSFC ; Agence Nationale de la Recherche (ANR) project TILT |
论文分区 | 二类 |
力学所作者排名 | 1 |
RpAuthor | Pumir, Alain |
引用统计 | |
文献类型 | 期刊论文 |
条目标识符 | http://dspace.imech.ac.cn/handle/311007/93344 |
专题 | 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. |
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