A Reynolds-averaged turbulence modelling approach to the maintenance of the Venus superrotation

A. Yoshizawa, H. Kobayashi, N. Sugimoto, N. Yokoi, Y. SHIMOMURA

研究成果: Article査読

1 被引用数 (Scopus)

抄録

A maintenance mechanism of an approximately linear velocity profile of the Venus zonal flow or superrotation is explored, with the aid of a Reynolds-averaged turbulence modelling approach. The basic framework is similar to that of Gierasch (Meridional circulation and maintenance of the Venus atmospheric rotation. J. Atmos. Sci. 1975, 32, 1038-1044) in the sense that the mechanism is examined under a given meridional circulation. The profile mimicking the observations of the flow is initially assumed, and its maintenance mechanism in the presence of turbulence effects is investigated from a viewpoint of the suppression of energy cascade. In the present work, the turbulent viscosity is regarded as an indicator of the intensity of the cascade. A novelty of this formalism is the use of the isotropic turbulent viscosity based on a non-local time scale linked to a large-scale flow structure. The mechanism is first discussed qualitatively. On the basis of these discussions, the two-dimensional numerical simulation of the proposed model is performed, with an initially assumed superrotation, and the fast zonal flow is shown to be maintained, compared with the turbulent viscosity lacking the non-local time scale. The relationship of the present model with the current general circulation model simulation is discussed in light of a crucial role of the vertical viscosity.

本文言語English
ページ(範囲)614-639
ページ数26
ジャーナルGeophysical and Astrophysical Fluid Dynamics
107
6
DOI
出版ステータスPublished - 2013 12

ASJC Scopus subject areas

  • 計算力学
  • 天文学と天体物理学
  • 地球物理学
  • 材料力学
  • 地球化学および岩石学

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