Origin of high kurtosis levels in the viscous sublayer : direct numerical simulation and experiment
Origin of high kurtosis levels in the viscous sublayer : direct numerical simulation and experiment
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DOI：
10.1063/1.868973
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发表时间：
1996-07
影响因子：
4.6
通讯作者：
Chang Xu;Zhengjun Zhang;D. Toonder;F. Nieuwstadt
中科院分区：
文献类型：
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作者：
Chang Xu;Zhengjun Zhang;D. Toonder;F. Nieuwstadt
在文献中，一个主要的差异报道的正常速度波动的峰度值接近的墙壁，发现从直接数值模拟和实验获得。这些高峰度水平的起源进行了分析与直接数值模拟的湍流槽道流的帮助。此外，详细分析了在近壁区的湍流管流的LDV测量与DNS的结果作为出发点。在这两个数据集，即DNS和实验中，发现类似的速度事件，有助于高峰度水平。这些事件的动力学可与布鲁克和汉拉蒂[物理流体A 5，1011（1993）]所述的流向涡的再生过程相关联。基于这一证据，我们得出结论，高峰度是一个真正的物理性质。它是由只出现在近壁区域的非常强烈的事件引起的，并且在时间和空间上都很罕见。罕见的AP…
In the literature, a major discrepancy is reported between the value of the kurtosis for the normal velocity fluctuations close to the wall as found from direct numerical simulations and obtained from experiments. The origin of these high kurtosis levels is analyzed with help of a direct numerical simulation of a turbulent channel flow. In addition, a detailed analysis of LDV measurements in the near‐wall region of a turbulent pipe flow is made with the results of the DNS as a starting point. In both data sets, i.e. DNS and experiments, similar velocity events were found that contribute to the high kurtosis level. The dynamics of these events can be associated with the regeneration process of streamwise vortices as described by Brooke and Hanratty [Phys. Fluids A 5, 1011 (1993)]. Based on this evidence, we conclude that the high kurtosis is of a truly physical nature. It is caused by very strong events that appear only in the near‐wall region and that are rare in time as well as in space. The very rare ap...