关键词: Rayleigh-Bé/
nard热对流/
温度边界层/
湍流/
并行直接数值模拟
English Abstract
Characteristics of flow and thermal boundary layer in turbulent Rayleigh-Bénard convection
Huang Mao-Jing,Bao Yun
1.Department of Applied Mechanics and Engineering, Sun Yat-sen University, Guangzhou 510275, China
Fund Project:Project supported by the National Natural Science Foundation of China (Grant Nos. 11372362, 11452002), the Fundamental Research Fund for the Central Universities, China (Grant No. 14lgjc02), and the Joint Funds of National Natural Science Foundation of China-Guangdong Provincial People's Government (second phase) Super Computational Science Application Research (Grant No. nsfc2015570).Received Date:07 April 2016
Accepted Date:25 July 2016
Published Online:05 October 2016
Abstract:The parallel direct method of direct numerical simulation (PDM-DNS) for Rayleigh-Bénard (RB) convection is used in this paper. The differences and similarities in flow characteristic between two-dimensional (2D) and three-dimensional (3D) turbulent RB convection are studied using mean field for Ra=109, 1010, 5×1010, and Pr=4.3. Each of 2D and 3D cases has a large-scale circulation and corner rolls. The shape of large-scale circulation becomes round and the size of corner roll turns small as Ra increases. In 2D RB convection, there are four corner vortices at the corner of the square cavity and a stable large-scale circulation which is elliptical. For spanwise averaged 3D RB convection with two corner vortices, large-scale circulation reveals spindle shape. Due to the characteristic of the corner roll, the region plume dominating is wider in 2D RB convection than in the spanwise-averaged 3D case. Further, the Ra-dependence of thermal boundary layer properties is also studied. The thermal boundary layer thickness is scaled with Ra and the scaling exponents of λθ with Ra in the 2D and 3D cases are very similar.
Keywords: Rayleigh-Bé/
nard convection/
thermal boundary layer/
turbulence/
PDM-DNS
