Applied Mathematics and Mechanics (English Edition) ›› 2019, Vol. 40 ›› Issue (10): 1449-1456.doi: https://doi.org/10.1007/s10483-019-2531-6

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Threshold and decay properties of transient isolated turbulent band in plane Couette flow

Jianzhou LU1, Jianjun TAO1, Weitao ZHOU1, Xiangming XIONG2   

  1. 1. CAPT-HEDPS, SKLTCS, Collaborative Innovation Center of IFSA, Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing 100871, China;
    2. The Program in Applied and Computational Mathematics, Princeton University, Princeton, NJ 08544, U.S.A
  • Received:2019-05-10 Revised:2019-05-28 Online:2019-10-01 Published:2019-09-17
  • Contact: Jianjun TAO E-mail:jjtao@pku.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Nos. 91752203, 11490553, and 11602148)

Abstract: By direct numerical simulations of the plane Couette flow (PCF) in a large computational domain, it is shown that an isolated turbulent band decays monotonically at low Reynolds numbers but experiences transient growth before the eventual relaminarization at moderate Reynolds numbers. The lower bound Reynolds number of the transient-growth regime is determined as 286. The width, length, and tilt angle of the isolated band structure are defined based on the disturbance kinetic energy in the mid-plane, and the geometric characteristics of the band can be described with a tilted rectangle. It is illustrated that before its eventual fragmentation, the isolated turbulent band decays in a style of longitudinal contraction, where the center, width, and tilt angle of the band keep almost constant but the band length contracts with a statistically constant velocity.

Key words: plane Couette flow (PCF), subcritical transition, turbulent band

2010 MSC Number: 

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