Abstract: Shear stress on the surface of columns and the low Reflow field of interstitial flow in column array is studied numerically inthis paper, with focuses on the difference of shear stress on thecolumn surface between solid body and permeable body. The porous models areused to simulate the region between the columns, and the structure ofcolumns. Shear stress is calculated based on Brinkman equation using thefinite volume method with proper boundary conditions. The numerical results showthat the penetration structure of columns can inflect the flow field andsignificantly reduce the shear stress and effective permeability.