Time dependent β-convection in rapidly rotating spherical shells
Time dependent β-convection in rapidly rotating spherical shells
复制标题
快速旋转球壳中与时间相关的 β 对流
DOI：
10.1063/1.1703530
复制
发表时间：
2004
影响因子：
4.6
通讯作者：
E. Dormy
中科院分区：
文献类型：
--
作者：
V. Morin;E. Dormy
研究了快速旋转球壳中非线性热对流的准地转(β)模型。我们研究了Prandtl数为1的Rayleigh数和Ekman数的范围内的依赖于时间的不稳定性。在对流开始以上，对于给定的Ekman数，增加瑞利数，我们再现了Busse[Phys.流体14,1301(2002)]对于三维情况：第一个转变导致摇摆流动；第二个转变导致时间上的混沌振荡和空间上的局部对流；然后第三个转变导致准周期弛豫振荡。这项研究表明，准地转模式包含所需的分叉序列。它允许研究三维模型在现有计算资源下无法获得的一系列Ekman数。降低Ekman数，我们意外地发现，对于略超临界的Rayleigh Nu，这三个转变都发生了。
A quasi-geostrophic, or β, model of nonlinear thermal convection in rapidly rotating spherical fluid shells is investigated. We study time dependent instabilities for a range of Rayleigh number and Ekman number with a Prandtl number set to the unity. Above the onset of convection, increasing the Rayleigh number for a given Ekman number, we reproduce the sequence of bifurcations described by Busse [Phys. Fluids 14, 1301 (2002)] for the three-dimensional case: A first transition results in vacillating flow; a second transition gives rise to chaotic oscillations in time and localized convection in space; then a third leads to quasi-periodic relaxation oscillations. This study shows that the quasigeostrophic model encompasses the desired bifurcation sequence. It allows the investigation of a range of Ekman numbers unavailable to three-dimensional models with present computing resources. Decreasing the Ekman number, we unexpectedly found that all three transitions occur for marginally supercritical Rayleigh nu...