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Heat transfer and flow structure of two-dimensional thermal convection over ratchet surfaces
Journal of Hydrodynamics ( IF 2.5 ) Pub Date : 2021-11-08 , DOI: 10.1007/s42241-021-0086-9
Cheng Wang 1 , Lin-feng Jiang 1 , He-chuan Jiang 1 , Chao Sun 1, 2 , Shuang Liu 1, 3
Affiliation  

This paper presents a numerical study of the Rayleigh-Bénard convection (RBC) in two-dimensional cells with asymmetric (ratchet) roughness distributed on the top and bottom surfaces. We consider two aspect ratios of roughness γ = 1, 2 and the range of the Rayleigh number 1.0 × 106Ra ≤ 2.0 × 1010 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 corner rolls, and the corner 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.



中文翻译:

棘轮表面二维热对流的传热与流动结构

本文介绍了二维单元中瑞利-贝纳对流 (RBC) 的数值研究,该单元具有分布在顶部和底部表面的不对称(棘轮)粗糙度。我们考虑粗糙度γ = 1、2 和瑞利数范围 1.0 × 10 6Ra ≤ 2.0 × 10 10和普朗特数Pr = 4 的两个纵横比。粗糙度对传热和流动的影响发现结构强烈依赖于Ra和粗糙度几何形状。我们发现粗糙度可以对二次角辊的组织产生显着影响,并且角辊明显受到粗糙度为中间值的抑制。在粗糙度存在的情况下,Nu值急剧跳跃,Ra值略有增加,伴随着大尺度流动结构和羽流动力学的剧烈变化。讨论和分析了棘轮方向对传热和流动结构的影响。

更新日期:2021-11-12
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