Heat transfer and flow structure of two-dimensional thermal convection over ratchet surfaces  

作　　者：Cheng Wang Lin-feng Jiang He-chuan Jiang Chao Sun Shuang Liu 

机构地区：[1]Center for Combustion Energy,Key Laboratory for Thermal Science and Power Engineering of Ministry of Education,Department of Energy and Power Engineering,Tsinghua University,Beijing 100084,China [2]Department of Engineering Mechanics,School of Aerospace Engineering,Tsinghua University,Beijing 100084,China [3]Yau Mathematical Sciences Center,Tsinghua University,Beijing 100084,China

出　　处：《Journal of Hydrodynamics》2021年第5期970-978,共9页水动力学研究与进展B辑（英文版）

基　　金：supported by the Natural Science Foundation of China(Grant Nos.11988102,91852202);the China Postdoctoral Science Foundation(Grant No.2019M660614).

摘　　要：This paper presents a numerical study of the Rayleigh-Benard convection(RBC)in two-dimensional cells with asymmetric(ratchet)roughness distributed on the top and bottom surfaces.We consider two aspect ratios of roughness y=1,2 and the range of the Rayleigh number 1.0 xlO6<Ra<2.0x1010 with the Prandtl number Pr=4.The influences of the roughness on the heat transfer and the flow structure are found to be strongly dependent on both Ra and the roughness geometry.We find that the roughness can have a significant influence on the organization of the secondary comer rolls,and the comer rolls are evidently suppressed by the roughness for intermediate values of Ra.In the presence of the roughness,a sharp jump of the Nu values is identified as the Ra value is slightly increased,accompanied with the dramatic changes of the large-scale flow structure and the plume dynamics.The influences of the ratchet orientation on the heat transfer and the flow structure are discussed and analyzed.

关 键 词：Turbulent convection ratchet roughness heat transfer flow structure 

分 类 号：O35[理学—流体力学]