Weakly decaying turbulence in an equivalent‐barotropic fluid
Weakly decaying turbulence in an equivalent‐barotropic fluid
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等效正压流体中的弱衰减湍流
DOI：
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发表时间：
1991
期刊：
影响因子：
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通讯作者：
J. McWilliams
中科院分区：
文献类型：
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作者：
V. Larichev;J. McWilliams
分析了等效正压流体（即强旋转极限下的浅水层）中湍流从随机、窄带小粘度初始条件演化的数值解。特别注意小变形半径的情况：解对能量和势熵的耗散都很弱；经过短暂的波数展宽初始间隔后，能量谱和位熵谱的形状几乎随时间变化，但它们的质心向更大尺度移动，并且相干涡旋结构自发地发展为轴对称位涡单极子的优选形状。针对小变形半径推导了渐近模型，其行为表现出等效正压模型的基本特征。分析解决方案以增加变形半径，范围从小到无限（即非发散的二维流）。在这个序列中，动力学进化...
Numerical solutions are analyzed for the evolution of turbulent flow in an equivalent‐barotropic fluid (i.e., a shallow water layer in the limit of strong rotation) from random, narrow‐band initial conditions with small viscosity. Particular attention is given to the regime of small deformation radius: the solutions are weakly dissipative of both energy and potential enstrophy; after a brief initial interval of broadening in wave number, the shapes of the energy and potential enstrophy spectra are nearly invariant in time but their centroids move toward larger scales, and coherent vortex structures spontaneously develop with a preferred shape of axisymmetric potential vorticity monopoles. An asymptotic model is derived for small deformation radius, and its behavior exhibits the essential features of the equivalent‐barotropic model. Solutions are analyzed for increasing deformation radii, ranging from small to infinite (i.e., nondivergent, two‐dimensional flow). In this sequence, both the dynamical evoluti...