On the self-organizing process of large scale shear flows
On the self-organizing process of large scale shear flows
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DOI：
10.1063/1.4817955
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发表时间：
2013-09-01
影响因子：
2.2
通讯作者：
Liu, Han-Li
中科院分区：
文献类型：
--
作者：
Newton, Andrew P. L.;Kim, Eun-jin;Liu, Han-Li
自组织调用作为一种范式来探索的过程中管理的剪切流的演变。通过检查的概率密度函数（PDF）的局部流动梯度（剪切），我们表明，剪切流达到一个准平衡状态，因为它的增长剪切平衡的剪切松弛。具体而言，PDF的本地剪切的数值计算和分析减少一维和一维模型，其中PDF收敛到一个双峰分布的情况下，有限的相关时间强迫。这种双峰PDF，然后示出再现在非线性模拟的二维流体动力学湍流。此外，双峰PDF被证明是从一个自组织剪切流与线性剖面。墨西哥湾流中的切变流也具有类似的双峰结构和线性分布，表明其具有自组织性。(C)2013 AIP Publishing LLC.
Self organization is invoked as a paradigm to explore the processes governing the evolution of shear flows. By examining the probability density function (PDF) of the local flow gradient (shear), we show that shear flows reach a quasi-equilibrium state as its growth of shear is balanced by shear relaxation. Specifically, the PDFs of the local shear are calculated numerically and analytically in reduced 1D and 0D models, where the PDFs are shown to converge to a bimodal distribution in the case of finite correlated temporal forcing. This bimodal PDF is then shown to be reproduced in nonlinear simulation of 2D hydrodynamic turbulence. Furthermore, the bimodal PDF is demonstrated to result from a self-organizing shear flow with linear profile. Similar bimodal structure and linear profile of the shear flow are observed in gulf stream, suggesting self-organization. (C) 2013 AIP Publishing LLC.