Spectral transfers in two-dimensional anisotropic flow
Spectral transfers in two-dimensional anisotropic flow
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二维各向异性流中的光谱传输
DOI：
10.1063/1.858308
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
W. Smyth
中科院分区：
文献类型：
--
作者：
W. Smyth
研究了二维剪切流中一维傅里叶谱中动能的非线性传递和拟能。详细的守恒定律揭示了闭合传输对的存在，这些传输包括源模式、接收者模式和平流模式，这些模式调解相互作用，但不直接受其影响。将谱传递诊断方法应用于两个简单的、线性不稳定的、初始平行的剪切流的研究，即Bickley射流和双曲切线剪切层。在每一种情况下，传输谱都被波-均流相互作用和与涡旋合并相关的低尺度叶栅所支配。叶栅是由大尺度涡旋的平流变形(即成丝)驱动的，在传递函数图中表现为非局域相互作用驱动的局地传输。
Nonlinear transfers of kinetic energy and enstrophy in the unidimensional Fourier spectrum that is obtained in a two‐dimensional shear flow are investigated. Detailed conservation laws reveal the existence of closed pairs of transfers that involve a source mode, a recipient mode, and an advecting mode, which mediates the interaction but is not directly affected by it. The methodology of spectral transfer diagnosis is applied in the study of two simple, linearly unstable, initially parallel shear flows, namely the Bickley jet and the hyperbolic‐tangent shear layer. In each case, the transfer spectra are found to be dominated by wave–mean flow interactions and by downscale cascades that are associated with vortex mergers. Cascades are driven by the advective deformation of small eddies by the large‐scale vortices (i.e., filamentation), and appear in the transfer function maps as local transfers driven by nonlocal interactions.