arXiv 0911.08412009-11physics.flu-dyn

无Richardson-Kolmogorov级联的Turbulence

Turbulence without Richardson-Kolmogorov cascade

Nicolas Mazellier, Christos Vassilicos

备注：: 37 pages, 25 figures, submitted to Physics of Fluids, revised version (shortened introduction and conclusion)
DOI：: 10.1063/1.3453708

摘要：

本文对一类低阻塞空间填充分形正方形网格产生的强湍流进行了实验研究。我们确认存在一个保护生产区域，然后是一个衰减区域，正如Hurst & Vassilicos（Physics of Fluids，2007）首次报道的那样。我们发现，中心线流向变化的湍流的统计特性的大部分可以缩放的尾流相互作用的长度尺度$x_*$。我们还证实了Seoud和Vassilicos（Physics of Fluids，2007）的发现，即积分长度尺度$L_u$与泰勒微尺度$λ$的比值在衰减区域保持恒定，而雷诺数$Re_λ$强烈减小。结果，在无边界剪切流和通常的网格产生的紊流中，由耗散率的$u'^{3}/L_u$标度导出的标度$L_{u}/λ\sim Re_λ$在这里不成立。然而，我们表明，比值$L_u/λ$是入口雷诺数$Re_0$的递增函数。这种非同寻常的解耦与George & Wang（Physics of Fluids，2009）提出的自保持单一长度尺度衰减均匀湍流一致，我们的结果与之进行了比较。

英文摘要：

We present an experimental investigation of intense turbulence generated by a class of low-blockage space-filling fractal square grids. We confirm the existence of a protacted production region followed by a decaying region, as first reported by Hurst & Vassilicos (Physics of Fluids, 2007). We show that the centerline streamwise variation of most of the statistical properties of the turbulent flow can be scaled by a wake interaction length-scale $x_*$. We also confirm the finding of Seoud and Vassilicos (Physics of Fluids, 2007) that the ratio of the integral length-scale $L_u$ to the Taylor micro-scale $λ$ remains constant in the decaying region whereas the Reynolds number $Re_λ$ strongly decreases. As a result the scaling $L_{u}/λ\sim Re_λ$ which follows from the $u'^{3}/L_u$ scaling of the dissipation rate in boundary-free shear flows and in usual grid-generated turbulence does not hold here. However, we show that the ratio $L_u/λ$ is an increasing function of the inlet Reynolds number $Re_0$. This extraordinary decoupling is consistent with a self-preserving single length-scale decaying homogeneous turbulence proposed by George & Wang (Physics of Fluids, 2009) with which our results are compared.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

摘要：

英文摘要：

相关论文