Velocity and turbulence field around permeable structure: Comparisons between laboratory and numerical experiments

The results of a comparison between laboratory tests and numerical modeling for flow around permeable structures are presented. Three different structures are experimentally considered, first one is solid and second one is permeable structures. The permeable structures are represented by glass beads of two diameters, 2.5 and 1.5 cm, resulting in porosity equal to 0.475 and 0.349, respectively. A macroscopic model that solves the Reynolds-averaged Navier-Stokes equations with a non-Darcy resistance law is developed to simulate the flow around and within the permeable structures. The numerical predictions show good agreements with the experimental results. In the cases of permeable structures, recirculation regions are shown to be elongated in the downstream direction due to the bleed flow passing through the permeable structure. The turbulence intensity is highly reduced, compared to the situation with a solid structure, in the region near the surface and just behind the structures for the turbulence flow over a permeable structure. Discharge over the permeable structure indicates a significant reduction of the channel capacity and non-uniform distribution in the streamwise direction.