Fractal iso-level sets in high-Reynolds-number scalar turbulence
Fractal iso-level sets in high-Reynolds-number scalar turbulence
复制标题
高雷诺数标量湍流中的分形等能级集
DOI：
10.1103/physrevfluids.5.044501
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发表时间：
2019
影响因子：
2.7
通讯作者：
P. Yeung
中科院分区：
文献类型：
--
作者：
K. Iyer;Jörg Schumacher;K. Sreenivasan;P. Yeung
本文研究了高雷诺数下被三维均匀各向同性湍流混合的被动标量等能级集的分形标度。施密特数是1。对于平均值两侧标量涨落的标准差在3美元以下的等值能级，可以得到分形盒的计数维D_F。尺度随等值能级而有系统地变化，平均而言，等值能级的最大值约为8/3美元；这一最大值也是几何测量理论的上界。我们将这一结果解释为湍流中的混合总是不完全的。当我们考虑以局部应变为条件的标量陡峭悬崖的空间支撑时，所有等电能级的唯一计盒维度得到了结果；该唯一维度约为4/3美元。
We study the fractal scaling of iso-levels sets of a passive scalar mixed by three-dimensional homogeneous and isotropic turbulence at high Reynolds numbers. The Schmidt number is unity. A fractal box-counting dimension $D_F$ can be obtained for iso-levels below about $3$ standard deviations of the scalar fluctuation on either side of its mean value. The dimension varies systematically with the iso-level, with a maximum of about $8/3$ for the iso-level at the mean; this maximum dimension also follows as an upper bound from the geometric measure theory. We interpret this result to mean that mixing in turbulence is always incomplete. A unique box-counting dimension for all iso-levels results when we consider the spatial support of the steep cliffs of the scalar conditioned on local strain; that unique dimension is about $4/3$.
关于形状和形式：波纹搅拌锋的群体平衡动力学
影响因子：
1.4
作者：
E. Villermaux
通讯作者：
E. Villermaux