Abstract: The problems of flow around bluff body exist widely in nature and engineering, which contains complex viscous flow mechanism. In this paper, the flow around a square cylinder with different thickness of porous media is numerically simulated by means of the lattice Boltzmann equation with Darcy-Brinkman-Forchheimer force model, and then the influence of porous media on the flow field characteristics of bluff body is studied. The results show that: compared with the impermeable cylinder, the flow structure is modulated by introducing the porous media layer under certain parameters, the evolution of the shear layer tends to be more symmetrical and stable, which reduces the interaction of vortex motions in the wake region and makes the vortex shedding more periodic, thus effectively reducing the amplitude of lift fluctuation, but increasing the drag in some extent. At the same time, this paper studies the surface porous media under high Reynolds number effect on square column, the results show that the porous medium wall that are farther apart for wake region of the shear layer, reduce the wake turbulence kinetic energy, and Reynolds stress peak area of the mobile to wake region, suppress the momentum exchange on either side of the square column, make the position of the momentum exchange occurred on wake region, Then the vortex street of the wake becomes more regular.

Key words: Lattice Boltzmann method, Porous media, flow around bluff body, Lift coefficie