Abstract In this paper, laminar flow through and over models of porous media is studied to characterize the flow at the onset of inertia. Horizontal, vertical or mesh arrays of circular rods are used to model the porous medium. The rods are arranged to cover solid volume fraction ranging from 0.03 to 0.49, and to fill approximately three-quarters of the depth of the test section. Each of the porous media models is tested in a refractive-index matched viscous fluid flow driven by pressure. The Reynolds number is also varied over an order of magnitude to cover the regime at which the porous medium flow just transitions from a Darcy to an inertia laminar flow regime. Velocity measurements are then obtained by a planar particle image velocimetry technique. The experimental data confirms that the averaged transition flow is indeed governed by the Brinkman equation if modeled with a new parametrization of the apparent viscosity, and modified with an equivalent permeability that accounts for the effects of inertia. Additionally, the results show that at such inertial flows, the interfacial region is the porous medium zone affected most by changes in Reynolds numbers. The data presented in this work provide tools for analytical and numerical validations, and the prediction of interfacial flow pertaining to isotropic porous media.

中文翻译：

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在惯性开始时通过和在多孔介质上流动的 PIV 研究。

摘要 在本文中，研究了多孔介质的层流穿过和穿过模型，以表征惯性开始时的流动。圆形棒的水平、垂直或网格阵列用于模拟多孔介质。杆被布置成覆盖范围从 0.03 到 0.49 的固体体积分数，并填充测试部分深度的大约四分之三。每个多孔介质模型都在由压力驱动的折射率匹配的粘性流体流中进行测试。雷诺数也在一个数量级上变化，以涵盖多孔介质流动刚从达西过渡到惯性层流状态的状态。然后通过平面粒子图像测速技术获得速度测量值。实验数据证实，如果用新的表观粘度参数化建模，并用考虑惯性效应的等效渗透率进行修改，则平均过渡流确实受 Brinkman 方程控制。此外，结果表明，在这种惯性流动中，界面区域是受雷诺数变化影响最大的多孔介质区域。这项工作中提供的数据为分析和数值验证以及与各向同性多孔介质相关的界面流动的预测提供了工具。界面区域是受雷诺数变化影响最大的多孔介质区域。这项工作中提供的数据为分析和数值验证以及与各向同性多孔介质相关的界面流动的预测提供了工具。界面区域是受雷诺数变化影响最大的多孔介质区域。这项工作中提供的数据为分析和数值验证以及与各向同性多孔介质相关的界面流动的预测提供了工具。