REYNOLDS DECOMPOSITION OF TURBULENCE CONTAINING SUPER-COHERENT STATES
REYNOLDS DECOMPOSITION OF TURBULENCE CONTAINING SUPER-COHERENT STATES
复制标题
含湍流超相干态的雷诺分解
DOI：
--
复制
发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Y. Peet
中科院分区：
文献类型：
--
作者：
R. Adrian;P. Sakievich;Y. Peet
我们解决了当某些流的平均和高阶统计量的时间平均值未能表现出边界条件和物理所施加的对称性时发生的问题。这样的失败使平均场的确定受到怀疑，使得应用雷诺分解变得困难，甚至不正确。我们一直在研究纵横比为6.3：1（直径：深度）的垂直圆柱体中的湍流瑞利-贝纳德对流（RBC）（Sakievich等人，2016），并将其作为示例来说明和解释这一现象。然而，有理由相信，从RBC发展的概念适用于其他湍流。在单位展弦比的圆柱体中，通常观察到平均流量不为零（Bodenschatz等人; Emran等人，2015年）。我们发现从HPC模拟，湍流RBC在一个宽的圆柱体的特征包含大尺度的运动，是均方周期的方位角方向。在平面图中，它们看起来像一个有点随机中心的上升（下降）流体的中心，“辐条”在径向方向上发出，如图1。辐条是水平的、径向取向的、反向旋转的滚动单元之间的暖（冷）流体上升（下降）的会聚区。最有活力的滚动细胞具有方位角周期性图1。在109瑞利数下，圆柱形几何形状中的RBC流动模式该流动在600次自由落体时间内平均。
We address the problem that occurs when time average values of mean and higher-order statistics of certain flows fail to exhibit the symmetry properties imposed by boundary conditions and physics. Such failures render determinations of the mean fields suspect, making it difficult, or even incorrect to apply Reynolds decomposition. We have been studying turbulent Rayleigh-Benard convection (RBC) in a 6.3:1 (diameter:depth) aspect-ratio vertical cylinder (Sakievich, et al. 2016), and it will be used as example to illustrate and explain this phenomenon. However, there are reasons to believe that the concepts that are developed from RBC pertain to other turbulent flows. In unit aspect ratio cylinders, it is commonly observed that the mean flow is non-zero (Bodenschatz, et al.; Emran, et al. 2015). We find from HPC simulations that turbulent RBC in a wide circular cylinder characteristically contains large-scale motions that are mean-square-periodic in the azimuthal-direction. In plan view they look like a somewhat randomly centered hub of rising (falling) fluid from which ‘spokes’ emanate in radial directions, iFgure 1. The spokes are convergence zones of warm (cool) fluid rising (falling) between horizontal, radially oriented, counter-rotating roll-cells. The most energetic roll cells have azimuthal periodicity Figure 1. RBC flow pattern at 109 Rayleigh number in a cylindrical geometry The flow is averaged over 600 free-fall times.
影响因子：
3.7
作者：
Emran, Mohammad S.;Schumacher, Joerg
通讯作者：
Schumacher, Joerg