Experimental investigation of interfacial conditions between fluid and porous layer formed by periodic arrays of circular and non-circular cylinders

In this experimental study, a flow through a two-dimensional channel partially containing porous media is investigated. A two-layer structure comprising of a saturated porous layer with an overlaying fluid flow layer in a rectangular horizontal channel is designed for the experiments. Flow characteristics at the interface between clear fluid and porous layer are investigated. The porous layer consists of cylindrical rod bundle placed horizontally on the side walls of the channel in arranged square arrays. In the experiments, water white oil is used as the working fluid to match the refractive index of the cylindrical rods made of Plexiglas. Visualizations and measurements have been acquired by digital particle image velocimetry system for the velocity profiles which help us to evaluate the interface velocity and slip coe cient at the interface region. The measurement of interface velocity profile is repeated for circular, square, and 45° rotated square cylindrical rods to understand the e ects of the structure of the interface region. It has been observed that dimensionless slip or interface velocity depends significantly on the surface structure at the interface region when cylindrical rods each with circular, square, and 45° rotated square cross-sections are used as porous medium. The volumetric flow rate can be changed according to the cross-sections of cylindrical rods. The permeability for the di erent arrangements of cylindrical rods is computed by an analytical study. The dimensionless slip velocity, slip coe cient, particle image velocimetry images, experimental and numerical velocity vector maps, and velocity profiles at the interface are presented.