Upscale energy transfer in three-dimensional rapidly rotating turbulent convection.
Upscale energy transfer in three-dimensional rapidly rotating turbulent convection.
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DOI：
10.1103/physrevlett.112.144501
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发表时间：
2014-04
影响因子：
8.6
通讯作者：
Antonio M. Rubio;K. Julien;E. Knobloch;J. Weiss
中科院分区：
文献类型：
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作者：
Antonio M. Rubio;K. Julien;E. Knobloch;J. Weiss
旋转的瑞利-贝纳德对流在快速旋转的极限下表现出一种湍流状态，称为地转湍流。这种状态是存在足够大的瑞利数代表的系统的热强迫，其特征在于由科里奥利力和压力梯度之间的领先秩序的平衡。这种湍流状态本身是不稳定的，会通过一个称为光谱凝结的过程产生更大规模的与深度无关的或正压涡旋结构。这一过程涉及一个具有正反馈回路的逆级联机制，大尺度正压涡旋借此组织小尺度对流涡旋。反过来，这些涡提供了一个动态演变的能源大尺度正压分量。正压动力学的动能谱是一致的k-3降尺度涡度拟能级联和一个高档级联，陡峭的k-3箱尺度凝结的形式。在同一时间的流量保持斜压对流成分与惯性范围一致的k-5/3频谱。冷凝过程类似于二维的类似过程，但完全是三维的。
Rotating Rayleigh-Bénard convection exhibits, in the limit of rapid rotation, a turbulent state known as geostrophic turbulence. This state is present for sufficiently large Rayleigh numbers representing the thermal forcing of the system, and is characterized by a leading order balance between the Coriolis force and pressure gradient. This turbulent state is itself unstable to the generation of depth-independent or barotropic vortex structures of ever larger scale through a process known as spectral condensation. This process involves an inverse cascade mechanism with a positive feedback loop whereby large-scale barotropic vortices organize small scale convective eddies. In turn, these eddies provide a dynamically evolving energy source for the large-scale barotropic component. Kinetic energy spectra for the barotropic dynamics are consistent with a k-3 downscale enstrophy cascade and an upscale cascade that steepens to k-3 as the box-scale condensate forms. At the same time the flow maintains a baroclinic convective component with an inertial range consistent with a k-5/3 spectrum. The condensation process resembles a similar process in two dimensions but is fully three-dimensional.