Spectral anisotropy in forced two-dimensional turbulence on a rotating sphere
Spectral anisotropy in forced two-dimensional turbulence on a rotating sphere
复制标题
旋转球体上强制二维湍流的光谱各向异性
DOI：
10.1063/1.869518
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发表时间：
1997
影响因子：
4.6
通讯作者：
S. Yoden
中科院分区：
文献类型：
--
作者：
T. Nozawa;S. Yoden
本文分析了近年来在直接数值模拟中获得的旋转球体上的二维强迫湍流数据集，研究了由于球体旋转引起的光谱各向异性。并将所得结果与先前的β平面实验结果进行了比较，以评价旋转球体的β平面近似。由于旋转的影响，向上的能量级联在一个特征总波数nβ附近停止，在这个特征总波数nβ处，线性“β-项”与非线性雅可比项相当。在波数空间（m,n）内，区域分量（m=0）的能量密度在n≤nβ范围内占主导地位，而下边缘翼型区域的能量密度很小。在高波数区n ~ nβ也发现了能量的各向异性分布；能量密度随纬向波数m的增加而减小。将球面几何中的流场投影在从赤道到两极的切平面上，以比较球面流场的分布。
The datasets on the forced two-dimensional turbulence on a rotating sphere obtained in our recent direct numerical simulations were analyzed to study the spectral anisotropy due to the rotation of the sphere. The results were also compared with those previously obtained in some β-plane experiments to assess the β-plane approximation of the rotating sphere. Owing to the effect of rotation the upward energy cascade ceases around a characteristic total wavenumber nβ at which the linear “β-term” is comparable to the nonlinear Jacobian term. The energy density of zonal components (m=0) is dominant in the range of n≲nβ while the energy is very small in an airfoil-shaped region at the lower edge in the wavenumber space (m,n). Anisotropic distribution of the energy is also found in the high wavenumber region n≳nβ; the energy density decreases as the zonal wavenumber m increases. The flow field in the spherical geometry is projected on some tangential planes from the equator to the poles to compare the spherical r...