{"title":"Heat transfer and flow structure in centrally-confined 2-D Rayleigh-Bénard convection","authors":"Cong Sun, Jian-zhao Wu, Xiao-hui Meng, Cai-xi Liu, Wei Xu, Yu-hong Dong, Quan Zhou","doi":"10.1007/s42241-024-0058-y","DOIUrl":null,"url":null,"abstract":"<div><p>Through direct numerical simulations, we investigated the flow structure and heat transfer of the centrally confined 2-D Rayleigh-Bénard (RB) convection over the Rayleigh number range 9 × 10<sup>5</sup> ≤ <i>Ra</i> ≤ 10<sup>9</sup> at a fixed Prandtl number <i>Pr</i> = 4.3. It is found that with increasing <i>Ra</i>, the number of convection rolls in the central vertical channel increases from zero to three. When there is no rolls in the vertical channel, the convective flow in central region is significantly influenced by the boundary layer, whereas when the convection rolls is generated in the vertical channel, the convective flows in central regions is free from the boundary layer limitation, and by defining the characteristic length, one obtains the heat transfer scaling law relation in vertical channel, i.e., <i>Nu</i><sub><i>vc</i></sub> ∼ <i>Ra</i><span>\n <sup>0.476±0.005</sup><sub><i>vc</i></sub>\n \n </span>, which could be the evidence of “ultimate regime”.</p></div>","PeriodicalId":637,"journal":{"name":"Journal of Hydrodynamics","volume":"36 4","pages":"772 - 780"},"PeriodicalIF":2.5000,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Hydrodynamics","FirstCategoryId":"5","ListUrlMain":"https://link.springer.com/article/10.1007/s42241-024-0058-y","RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
Through direct numerical simulations, we investigated the flow structure and heat transfer of the centrally confined 2-D Rayleigh-Bénard (RB) convection over the Rayleigh number range 9 × 105 ≤ Ra ≤ 109 at a fixed Prandtl number Pr = 4.3. It is found that with increasing Ra, the number of convection rolls in the central vertical channel increases from zero to three. When there is no rolls in the vertical channel, the convective flow in central region is significantly influenced by the boundary layer, whereas when the convection rolls is generated in the vertical channel, the convective flows in central regions is free from the boundary layer limitation, and by defining the characteristic length, one obtains the heat transfer scaling law relation in vertical channel, i.e., Nuvc ∼ Ra0.476±0.005vc, which could be the evidence of “ultimate regime”.
期刊介绍:
Journal of Hydrodynamics is devoted to the publication of original theoretical, computational and experimental contributions to the all aspects of hydrodynamics. It covers advances in the naval architecture and ocean engineering, marine and ocean engineering, environmental engineering, water conservancy and hydropower engineering, energy exploration, chemical engineering, biological and biomedical engineering etc.