Velocity measurements of a shear flow penetrating a porous medium
Velocity measurements of a shear flow penetrating a porous medium
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DOI：
10.1017/s0022112003005986
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发表时间：
2003-10
影响因子：
3.7
通讯作者：
M. Tachie;D. F. James;I. G. Currie
中科院分区：
文献类型：
--
作者：
M. Tachie;D. F. James;I. G. Currie
本文报道了通过纤维状多孔介质模型的简单剪切流的实验研究。流场建立在一个静止的内缸和一个匀速旋转的同心外缸之间。模型介质是一组有规则的棒，这些棒沿流动方向排列，并填充圆柱体之间的一小部分环形空间。研究了具有圆形、方形和三角形截面的棒，阵列的固体体积分数范围为0.01 ~ 0.16。当工作流体为粘性油时，雷诺数远小于1。使用粒子图像测速法进行的速度测量聚焦于每个被测阵列边缘周围的区域。测量结果显示，对于固体体积分数高于最小值的棒材形状，在棒材最外层的两个圆之间形成涡流。速度数据用于计算界面滑移速度和多孔介质与外部剪切流界面处的平均速度。数据表明，滑移速度随固体体积分数的增加而衰减，正如预期的那样，但发现速度几乎与杆的形状和组成阵列的杆的圆数无关。滑移速度仅为Brinkman方程预测值的24-30%。
This paper reports an experimental investigation of simple shear flow penetrating a model of a fibrous porous medium. The flow field is established between a stationary inner cylinder and a concentric outer cylinder rotating at a constant speed. The model medium is a regular array of rods which are oriented across the flow and which fill a fraction of the annular space between the cylinders. Rods with circular, square and triangular cross-sections are investigated, and the solid volume fraction of the arrays ranges from 0.01 to 0.16. With a viscous oil as the working fluid, the Reynolds number is much less than unity. Velocity measurements made using particle image velocimetry focus on the region around the edge of each array tested. The measurements reveal that eddies form between the two outermost circles of rods, for solid volume fractions above a minimum value which depends on rod shape. The velocity data are used to find the interfacial slip velocity and the average velocity at the interface between the porous medium and the outer shear flow. The data demonstrate that the slip velocity decays with increasing solid volume fraction, as expected, but the velocity is found to be nearly independent of rod shape and of the number of circles of rods comprising an array. It is also found that the slip velocity is only 24–30% of the value predicted from the Brinkman equation.