论文标题
在均质各向同性湍流中的矢量无效的聚类
Clustering of vector nulls in homogeneous isotropic turbulence
论文作者
论文摘要
我们分析了速度，拉格朗日加速度和涡度的矢量零，来自[40-610] $ in $re_λ\ $re_λ\的强制均质性湍流的直接数值模拟。我们表明，速度无效的聚类比加速度和涡度零值的聚类强得多。然而，这些加速度和涡度零是比速度空的密集的。我们使用$re_λ$并具有特征性的湍流长度尺度研究这些无效点的簇的缩放。我们还分析了具有stokes数字的点惯性粒子的数据集$ st = 0.5 $，3和6，$re_λ= 240 $。惯性颗粒与一定程度的聚类表现出优先浓度，类似于Lagrangian加速度nulls聚类的某些特性，与所提出的扫描形成的扫描机理一致。
We analyze the vector nulls of velocity, Lagrangian acceleration, and vorticity, coming from direct numerical simulations of forced homogeneous isotropic turbulence at $Re_λ\in [40-610]$. We show that the clustering of velocity nulls is much stronger than those of acceleration and vorticity nulls. These acceleration and vorticity nulls, however, are denser than the velocity nulls. We study the scaling of clusters of these null points with $Re_λ$ and with characteristic turbulence lengthscales. We also analyze datasets of point inertial particles with Stokes numbers $St = 0.5$, 3, and 6, at $Re_λ= 240$. Inertial particles display preferential concentration with a degree of clustering that resembles some properties of the clustering of the Lagrangian acceleration nulls, in agreement with the proposed sweep-stick mechanism of clustering formation.
