Fourier signature of filamentary vorticity structures in two-dimensional turbulence
Fourier signature of filamentary vorticity structures in two-dimensional turbulence
复制标题
二维湍流中丝状涡度结构的傅里叶特征
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
R. Sánchez
中科院分区：
文献类型：
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作者：
J. Reynolds;D. Newman;P. Terry;R. Sánchez
结果表明，相干区的各向同性二维（2D）湍流可以清楚地确定在傅立叶频谱的相位部分。某些谱相位事件特别突出，并且在对应于耗散范围的波数范围内更强。结果表明，这些事件与空间局部的对流结构在二维涡度场，历史上一直与耗散的不稳定性。所确定的相位签名提供了一个特别透明的诊断的时间演变的相干耦合的不同尺度的各向异性间歇性耗散事件。这些结果打开的可能性，使用相位的傅立叶变换作为一种新的湍流诊断，识别和定量表征有关的耗散事件的细节。
It is shown that coherent regions of isotropic two-dimensional (2D) turbulence can be clearly identified in the phase part of the Fourier spectrum. Certain spectral phase events are particularly prominent, and are much stronger in the range of wave numbers corresponding to the dissipation range. It is shown that these events are associated with spatially localized filamentary structures in the 2D vorticity field that historically have been related to the intermittency of dissipation. The identified phase signature provides a particularly transparent diagnostic of the temporal evolution of the coherent coupling of disparate scales in anisostropic intermittent dissipative events. These results open the possibility of using the phase of the Fourier transform as a new turbulence diagnostic that identifies and quantitatively characterizes details pertaining to dissipative events.