論文

査読有り
2016年4月

Regular flow reversals in Rayleigh-Benard convection in a horizontal magnetic field

PHYSICAL REVIEW E
  • Yuji Tasaka
  • ,
  • Kazuto Igaki
  • ,
  • Takatoshi Yanagisawa
  • ,
  • Tobias Vogt
  • ,
  • Till Zuerner
  • ,
  • Sven Eckert

93
4
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.1103/PhysRevE.93.043109
出版者・発行元
AMER PHYSICAL SOC

Magnetohydrodynamic Rayleigh-Benard convection was studied experimentally using a liquid metal inside a box with a square horizontal cross section and aspect ratio of five. Systematic flow measurements were performed by means of ultrasonic velocity profiling that can capture time variations of instantaneous velocity profiles. Applying a horizontal magnetic field organizes the convective motion into a flow pattern of quasi-two-dimensional rolls arranged parallel to the magnetic field. The number of rolls has the tendency to decrease with increasing Rayleigh number Ra and to increase with increasing Chandrasekhar number Q. We explored convection regimes in a parameter range, at 2 x 10(3) < Q < 10(4) and 5 x 10(3) < Ra < 3 x 10(5), thus extending the regime diagram provided by Yanagisawa et al. [T. Yanagisawa et al., Phys. Rev. E 88, 063020 (2013)]. Three regimes were identified, of which the regime of regular flow reversals in which five rolls periodically change the direction of their circulation with gradual skew of the roll axes can be considered as the most remarkable one. The regime appears around a range of Ra/Q = 10, where irregular flow reversals were observed in Yanagisawa et al. We performed the proper orthogonal decomposition (POD) analysis on the spatiotemporal velocity distribution and detected that the regular flow reversals can be interpreted as a periodic emergence of a four-roll state in a dominant five-roll state. The POD analysis also provides the definition of the effective number of rolls as a more objective approach.

Web of Science ® 被引用回数 : 19

リンク情報
DOI
https://doi.org/10.1103/PhysRevE.93.043109
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000373586200009&DestApp=WOS_CPL

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