論文

査読有り
2016年9月

Numerical studies on convective stability and flow pattern in three-dimensional spherical mantle of terrestrial planets

GEOPHYSICAL JOURNAL INTERNATIONAL
  • Takatoshi Yanagisawa
  • ,
  • Masanori Kameyama
  • ,
  • Masaki Ogawa

206
3
開始ページ
1526
終了ページ
1538
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.1093/gji/ggw226
出版者・発行元
OXFORD UNIV PRESS

We explore thermal convection of a fluid with a temperature-dependent viscosity in a basally heated 3-D spherical shell using linear stability analyses and numerical experiments, while considering the application of our results to terrestrial planets. The inner to outer radius ratio of the shell f assumed in the linear stability analyses is in the range of 0.11-0.88. The critical Rayleigh number R-c for the onset of thermal convection decreases by two orders of magnitude as f increases from 0.11 to 0.88, when the viscosity depends sensitively on the temperature, as is the case for real mantle materials. Numerical simulations carried out in the range of f = 0.11-0.55 show that a thermal boundary layer (TBL) develops both along the surface and bottom boundaries to induce cold and hot plumes, respectively, when f is 0.33 or larger. However, for smaller f values, a TBL develops only on the bottom boundary. Convection occurs in the stagnant-lid regime where the root mean square velocity on the surface boundary is less than 1 per cent of its maximum at depth, when the ratio of the viscosity at the surface boundary to that at the bottom boundary exceeds a threshold that depends on f. The threshold decreases from 10(6.5) at f = 0.11 to 10(4) at f = 0.55. If the viscosity at the base of the convecting mantle is 10(20)-10(21) Pa s, the Rayleigh number exceeds R-c for Mars, Venus and the Earth, but does not for the Moon and Mercury; convection is unlikely to occur in the latter planets unless the mantle viscosity is much lower than 10(20) Pa s and/or the mantle contains a strong internal heat source.

Web of Science ® 被引用回数 : 4

リンク情報
DOI
https://doi.org/10.1093/gji/ggw226
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000384650400007&DestApp=WOS_CPL

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