Lagrangian velocity autocorrelation in isotropic turbulence
Lagrangian velocity autocorrelation in isotropic turbulence
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DOI：
10.1063/1.857922
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发表时间：
1991-08
影响因子：
4.6
通讯作者：
Y. Kaneda;T. Gotoh
中科院分区：
文献类型：
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作者：
Y. Kaneda;T. Gotoh
本文分析了各向同性衰减湍流中小时滞τ= s-t在时间s和t的拉格朗日和欧拉速度自相关RL（s，t）和RE（s，t），并指出在适当的条件下，对于三维小时滞τ，RE≤RL，与能谱的形式无关。通过二维直接数值模拟研究了不受小τ限制的RE和RL的行为。通过拉格朗日重整化近似得到的RL值与模拟结果以及三维模拟和实验的现有数据吻合良好。
An analysis is made of the Lagrangian and the Eulerian velocity autocorrelations RL(s,t) and RE(s,t) at times s and t for small time lag τ=s−t in isotropic decaying turbulence, and it is shown that under appropriate conditions RE≤RL for small τ in three dimensions, irrespective of the form of the energy spectrum. The behaviors of RE and RL not limited to small τ are studied by direct numerical simulations in two dimensions. The values of RL obtained by the Lagrangian renormalized approximation are found to be in good agreement with the simulations and with the existing data of three‐dimensional simulations and experiments.