Large Eddy Simulations of Rayleigh-Bénard Convection in a Cubic Cavity  

作　　者：Tian Qin Yingying Luo Jiemin Zhan Wenqing Hu Yutian Li Ziwei Huang Tian Qin;Yingying Luo;Jiemin Zhan;Wenqing Hu;Yutian Li;Ziwei Huang(Department of Applied Mechanics and Engineering, School of Aeronautics and Astronautics, Shenzhen Campus of Sun Yat-sen University, Shenzhen, China)

机构地区：[1]Department of Applied Mechanics and Engineering, School of Aeronautics and Astronautics, Shenzhen Campus of Sun Yat-sen University, Shenzhen, China

出　　处：《Open Journal of Fluid Dynamics》2023年第3期177-190,共14页流体动力学（英文）

摘　　要：This paper conducts a Large Eddy Simulation (LES) of Rayleigh Bénard convection in a cubic cavity based on the WMLES S-Omega subgrid-scale model. For a cubic cavity with a vertical temperature difference of 6.7°C and 20°C, the velocity pulsation profiles and the mean velocity profiles of the vertical section in the middle of the cubic cavity were simulated, respectively. And they are consistent with the experiment results. Furthermore, the mean velocity field of the vertical cross-section in the middle of the cavity was calculated. Structures of the mean velocity field in the two cases are similar. A counterclockwise large vortex is found to occupy the cavity, and there are two small clockwise vortices in the lower left and upper right corners, and the mean velocity fields at two different temperature differences are consistent with the experimental results. The two-dimensional instantaneous temperature field and mean temperature field with different cross-sections in the z-direction, as well as the three-dimensional instantaneous isothermal surface structure, indicate that the large-scale circulation motion within the cubic cavity is moving diagonally. In addition, the structure of the mean streamline also illustrates this viewpoint. For the reverse vortex formed at two corners in the mean streamline structure, we used the Q criterion to identify and obtain two vortex structures similar to boomerangs. The basic turbulent structure in RB thermal convection includes the rising and falling plumes generated by buoyancy effects.This paper conducts a Large Eddy Simulation (LES) of Rayleigh Bénard convection in a cubic cavity based on the WMLES S-Omega subgrid-scale model. For a cubic cavity with a vertical temperature difference of 6.7°C and 20°C, the velocity pulsation profiles and the mean velocity profiles of the vertical section in the middle of the cubic cavity were simulated, respectively. And they are consistent with the experiment results. Furthermore, the mean velocity field of the vertical cross-section in the middle of the cavity was calculated. Structures of the mean velocity field in the two cases are similar. A counterclockwise large vortex is found to occupy the cavity, and there are two small clockwise vortices in the lower left and upper right corners, and the mean velocity fields at two different temperature differences are consistent with the experimental results. The two-dimensional instantaneous temperature field and mean temperature field with different cross-sections in the z-direction, as well as the three-dimensional instantaneous isothermal surface structure, indicate that the large-scale circulation motion within the cubic cavity is moving diagonally. In addition, the structure of the mean streamline also illustrates this viewpoint. For the reverse vortex formed at two corners in the mean streamline structure, we used the Q criterion to identify and obtain two vortex structures similar to boomerangs. The basic turbulent structure in RB thermal convection includes the rising and falling plumes generated by buoyancy effects.

关 键 词：Large Eddy Simulation Rayleigh-Bénard Convection Cubic Cavity Plume Flow 

分 类 号：O35[理学—流体力学]