A direct numerical simulation study on the possibility of macroscopic turbulence in porous media: Effects of different solid matrix geometries, solid boundaries, and two porosity scales
A direct numerical simulation study on the possibility of macroscopic turbulence in porous media: Effects of different solid matrix geometries, solid boundaries, and two porosity scales
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DOI：
10.1063/1.4949549
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发表时间：
2016-06
影响因子：
4.6
通讯作者：
M. Uth;Yan Jin;A. Kuznetsov;H. Herwig
中科院分区：
文献类型：
--
作者：
M. Uth;Yan Jin;A. Kuznetsov;H. Herwig
在这项研究中，我们讨论了多孔介质中的湍流结构在尺寸上是否受到孔尺度的限制，或者涡旋的尺寸是否可能超过孔尺度，从而导致宏观相干结构的形成。基于多孔介质中直接的数值模拟，我们得出结论：湍流涡旋的大小受孔隙大小的限制，从而引出了孔隙尺度盛行假说(PSPH)。我们通过考虑四种不同的多孔矩阵来证明这一假设。特别地，我们模拟了二维矩阵、三维无边界矩阵、由两个平行的固体壁围成的三维矩阵以及具有两个特征孔隙尺度的三维矩阵中的湍流流动。对四种模拟多孔基质的模拟结果支持PSPH。然而，如果固体基质具有不止一个长度尺度的特征，那么湍流结构是否能够达到最大孔隙尺度的尺寸仍是一个部分悬而未决的问题。
In this study, we address the question of whether turbulent structures in a porous medium are restricted in size by the pore scale or whether the size of eddies may exceed the pore scale, leading to the formation of macroscopic coherent structures. Based on direct numerical simulations in porous media, we conclude that the size of turbulent eddies is restricted by the pore size, leading to the pore scale prevalence hypothesis (PSPH). We prove this hypothesis by considering four different porous matrices. In particular, we simulated turbulent flow in a two-dimensional matrix, a three-dimensional unbounded matrix, a three-dimensional matrix bounded by two parallel solid walls, and a three-dimensional matrix with two characteristic pore scales. The obtained results for the four simulated porous matrices support the PSPH. However, there is a partly open question of whether turbulent structures can reach the size of the largest pore scale if the solid matrix is characterized by more than one length scale.