A Reynolds-averaged turbulence modelling approach to the maintenance of the Venus superrotation
A Reynolds-averaged turbulence modelling approach to the maintenance of the Venus superrotation
复制标题
维持金星超自转的雷诺平均湍流建模方法
DOI：
10.1080/03091929.2013.803546
复制
发表时间：
2013
影响因子：
1.3
通讯作者：
Yutaka Shimomura
中科院分区：
文献类型：
--
作者：
Akira Yoshizawa;Hiromichi Kobayashi;Norihiko Sugimoto;Nobumitsu Yokoi;Yutaka Shimomura
金星纬向流或超旋转的近似线性速度剖面的维护机制进行了探讨，与援助的一个平均湍流模拟方法。其基本框架与Gierasch（经向环流和金星大气旋转的维持）的框架相似。J. Atmos。Sci. 1975，32，1038-1044），在这个意义上，该机制是在一个给定的双相循环下进行检查。最初假设的轮廓模仿的流动的观察，并在湍流效应的存在下，其维护机制的能量级联抑制的观点进行了研究。在本工作中，湍流粘度被视为一个指标的强度的级联。这种形式主义的一个新奇是使用的各向同性湍流粘度的基础上的非本地时间尺度链接到一个大规模的流结构。首先定性地讨论了该机制。在这些讨论的基础上，所提出的模型进行了二维数值模拟，与初始假设的超旋转，和快速的纬向流被证明是保持，相比，湍流粘度缺乏非本地时间尺度。根据垂直粘性的关键作用，讨论了本模式与当前大气环流模式模拟的关系。
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.