Journal of Shanghai University(Natural Science Edition) ›› 2021, Vol. 27 ›› Issue (6): 1038-1046.doi: 10.12066/j.issn.1007-2861.2225

• Research Articles • Previous Articles     Next Articles

Effect of surface roughness on flow structures of turbulent Rayleigh-Bénard convection

YANG Jianlin1,2, ZHANG Yizhao1,2, ZHOU Quan1,2()   

  1. 1. School of Mechanics and Engineering Science, Shanghai University, Shanghai 200444, China
    2. Shanghai Institute of Applied Mathematics and Mechanics, Shanghai University, Shanghai 200072, China
  • Received:2020-02-24 Online:2021-12-31 Published:2020-06-15
  • Contact: ZHOU Quan E-mail:qzhou@shu.edu.cn

Abstract:

Most thermal convection phenomena in nature have rough boundaries. Thus, the study of Rayleigh-Bénard (RB) turbulent thermal convection on rough surfaces is theoretically and practically significant in understanding turbulent heat transfer and flow structures. In this study, the effect of two-dimensional rough surfaces on flow structures of turbulent RB convection is investigated through numerical simulations. The main parameters, the Rayleigh number (Ra) and Prandtl number (Pr), were 10$^{7 }\le $ $Ra\le 10^{9}$ and $Pr = 0.7.$ An isosceles right-angle triangle of the rough element shape was used for calculations. The results showed that the inhibition of the rough element on the large-scale circulation and the enhancement of the rough element on the plume generation and secondary vortices led to the complexity of the Reynolds number (Re) variation and the abnormal scaling relationship between Ra and Re.

Key words: Rayleigh-Bénard, turbulent thermal convection, rough, flow structure, Reynolds number

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