Connection between pore-scale and macroscopic flow characteristics of recirculating wake behind a porous cylinder

Abstract

The wake structure behind a porous square cylinder is numerically investigated by using both pore-scale and macroscopic approaches. The pore-scale simulations (PSSs) concern about the steady flow through and around square arrays of multiple circular cylinders with a wide range of solid fraction. The macroscopic porous media model (PMM) employed is the generalized equation, where the dimensionless permeability Dam is assigned based on the macroscopic permeability Das estimated from PSS via Darcy's law. The connection between pore-scale and macroscopic flow properties is studied in terms of the flow pattern, the geometric parameters, and the occurrence of the recirculating wake behind the array. It is found that the consistency between PSS and PMM is highly dependent on the ratio of Das and Dam. Discussions in terms of the scale analysis of PMM, the discrepancy between Dam and Das, and the effects of stress-jump parameters are also provided.