Asymmetry of Velocity Increments in Fully Developed Turbulence and the Scaling of Low-Order Moments.
Asymmetry of Velocity Increments in Fully Developed Turbulence and the Scaling of Low-Order Moments.
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DOI：
10.1103/physrevlett.77.1488
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发表时间：
1996-08
影响因子：
8.6
通讯作者：
Sreenivasan;Vainshtein;Bhiladvala;San Gil I;Chen;Cao
中科院分区：
文献类型：
--
作者：
Sreenivasan;Vainshtein;Bhiladvala;San Gil I;Chen;Cao
研究了湍流管流和箱体内模拟均匀湍流中速度增量的正负部分(PP)和负部分(NP)的定标问题。对于单位以上的矩阶数，在所有间隔距离内，NP的矩都大于PP的矩，PP的标度指数大于NP的标度指数。对于单位以下的矩阶数，速度增量的绝对值、Np的绝对值以及PP的绝对值都具有随矩阶数q线性变化的标度指数，但明显大于qy3。PACS号：47.27Ak，47.27Jv湍流中的速度脉动Usx；Td是一种大尺度的、非普遍的特征。Kolmogorov在[1]中引入了所谓的结构函数来研究普适性质。对于x方向上的速度分量u，定义(对于整数q)结构函数为：Sqsr d；k D u q L；k f u S x 1 r d 2 u S xdg q L。(1)期望结构在惯性范围[2]中的函数是分离距离r的某个幂；即，Sq，rz
A study is made of the scaling of the positive part (PP) and the negative part (NP) of velocity increments in turbulent pipe flow and in simulated homogeneous turbulence in a box. For moment orders above unity, the moments of NP are larger than those of PP for all separation distances, and the scaling exponents for PP are larger than those for NP. For moment orders below unity, the absolute value of the velocity increment and of NP, as well as PP, possess scaling exponents which vary linearly with the moment order q, though apparently greater than qy3. [S0031-9007(96)00976-3] PACS numbers: 47.27.Ak, 47.27.Jv The velocity fluctuation usx; td in a turbulent flow is a large scale feature and nonuniversal. Kolmogorov [1] introduced the so-called structure functions to study universal properties. Specializing to the velocity component u in the direction x, one defines (for integer q) the structure functions as Sqsr d; k D u q l;k f u s x 1 r d 2 u s xdg q l . (1) It is expected that the structure functions in the inertial range [2] scale as some power of the separation distance r; that is, Sq , r z