A numerical study on statistical characteristics of amplitude fluctuations in a wave turbulence
A numerical study on statistical characteristics of amplitude fluctuations in a wave turbulence
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DOI：
10.1016/j.physd.2011.04.005
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发表时间：
2011-07-15
影响因子：
4
通讯作者：
Yokoyama, Naoto
中科院分区：
文献类型：
--
作者：
Tanaka, Mitsuhiro;Yokoyama, Naoto
本文对具有非衰减型色散关系的Hamilton系统，研究了波动湍流中各分量波的能量s = vertical bar a（k）vertical bar（2）及其时间导数S = d vertical bar a（k）vertical bar（2）/dt的涨落统计特性。已经发现，在独立实现之间评估的s和S的概率密度函数（PDF）几乎等同于在单个实现中在k空间中的邻近模式之间评估的PDF。因此，在实现上的平均和在单个实现中的附近模式上的平均是可互换的。还发现s的PDF随时间向具有两个自由度的chi（2）分布演化，而在任何波数k处，在谱的外围（大k区域）和在含能范围（小k区域）中，都朝着拉普拉斯分布（或双侧指数分布）发展。(C)2011 Elsevier B. V.保留所有权利。
A series of numerical studies has been performed to investigate the statistical characteristics of fluctuations of energy s = vertical bar a(k)vertical bar(2) of each component wave and its time derivative S = d vertical bar a(k)vertical bar(2)/dt in a wave turbulence for a Hamiltonian system with a non-decay type dispersion relation. It has been found that the probability density functions (PDF) of s and S evaluated among independent realizations are almost equivalent to the PDF's evaluated among nearby modes in the k space in a single realization. Therefore, the averaging over the realizations and that over the nearby modes in a single realization are interchangeable. It has also been found that the PDF of s evolves in time toward the chi(2) distribution with two degrees of freedom, while that of. evolves toward the Laplace distribution (or the two-sided exponential distribution) at any wavenumber k, both in the peripheral of the spectrum (large k region) and in the energy-containing range (small k region). (C) 2011 Elsevier B.V. All rights reserved.