Oscillating convection and reversal flow in connected cavities

Yue Xiao, Jianjun Tao, Xue Ma, and Xiangming Xiong
Phys. Rev. E 98, 063109 – Published 20 December 2018

Abstract

The two-dimensional natural convection of air in upper and a lower square cavities connected with a vertical vent is studied numerically and theoretically. At high Rayleigh numbers (Ra), it is revealed by the dynamic-mode-decomposition method that the plumes yield to a new sway mode, where the plumes oscillate in the azimuthal direction around the vent ends. In particular, when Ra is high enough, a reversal convection occurs, i.e., the dominating large-scale circulation changes its flow direction quasiperiodically. A van der Pol–type model is developed based on the momentum and the energy equations, and the reversal phenomenon is explained in terms of the relaxation oscillation caused by the competition between the nonlinear advection and the thermal diffusion.

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  • Received 16 August 2018

DOI:https://doi.org/10.1103/PhysRevE.98.063109

©2018 American Physical Society

Physics Subject Headings (PhySH)

Fluid Dynamics

Authors & Affiliations

Yue Xiao, Jianjun Tao*, and Xue Ma

  • SKLTCS and CAPT-HEDPS, Collaborative Innovation Center of IFSA, Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing 100871, P. R. China

Xiangming Xiong

  • School of Mathematics and Statistics, Shenzhen University, Shenzhen 518060, P. R. China

  • *jjtao@pku.edu.cn

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Issue

Vol. 98, Iss. 6 — December 2018

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