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Effect of Boundary Layers Asymmetry on Heat Transfer Efficiency in Turbulent Rayleigh-Bernard Convection at Very High Rayleigh Numbers
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SYSNO ASEP 0383815 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Effect of Boundary Layers Asymmetry on Heat Transfer Efficiency in Turbulent Rayleigh-Bernard Convection at Very High Rayleigh Numbers Author(s) Urban, Pavel (UPT-D) RID, ORCID, SAI
Hanzelka, Pavel (UPT-D) RID, ORCID, SAI
Králík, Tomáš (UPT-D) RID, ORCID, SAI
Musilová, Věra (UPT-D) RID, SAI, ORCID
Srnka, Aleš (UPT-D) RID, ORCID, SAI
Skrbek, L. (CZ)Number of authors 6 Source Title Physical Review Letters. - : American Physical Society - ISSN 0031-9007
Roč. 109, č. 15 (2012), 154301:1-4Number of pages 4 s. Language eng - English Country US - United States Keywords thermal-convection Subject RIV BK - Fluid Dynamics R&D Projects GPP203/12/P897 GA ČR - Czech Science Foundation (CSF) ED0017/01/01 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) Institutional support UPT-D - RVO:68081731 UT WOS 000309590300019 EID SCOPUS 84867311682 DOI https://doi.org/10.1103/PhysRevLett.109.154301 Annotation The heat transfer efficiency in turbulent Rayleigh-Benard convection is investigated experimentally, in a cylindrical cell of height 0.3 m, diameter 0.3 m. We show that for Rayleigh numbers 10(12) less than or similar to Ra less than or similar to 10(15) the Nusselt number closely follows Nu proportional to Ra-1/3 if the mean temperature of the working fluid-cryogenic helium gas-is measured by small sensors directly inside the cell at about half of its height. In contrast, if the mean temperature is determined in a conventional way, as an arithmetic mean of the bottom and top plate temperatures, the Nu(Ra) proportional to Ra-gamma displays spurious crossover to higher gamma that might be misinterpreted as a transition to the ultimate Kraichnan regime. Workplace Institute of Scientific Instruments Contact Martina Šillerová, sillerova@ISIBrno.Cz, Tel.: 541 514 178 Year of Publishing 2013
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