Lattice Boltzmann Method Used to Simulate an Unsteady Flow Around an Obstacle in Laminar Regime

International audienceThis work deals with the application of the lattice Boltzmann method to simulate the unsteady laminar flow around a confined square obstacle. For this configuration, we can observe some regimes that fluid may occur during its flowing. We have determined numerically the flow behavior for linear and stable regime. The variable aspect of the flow observed depends on the Reynolds number. In this study, we determine the velocity fields for a various Reynolds numbers by resolving the Navier-Stokes equations using the Lattice Boltzmann Method with BGK schema. This method is a recent extension of the LB method which demonstrated its potential for describing incompressible flow around an obstacle. A numerical study of 2D and 3D problem around a square obstacle using the Lattice Boltzmann Method with BGK schema is presented for an unsteady flow in laminar regime. The flow behavior in a horizontal channel with a rectangular cross-section, where a squared obstacle is placed in the middle, is discussed. In the 2D simulation, the obtained numerical results show a good agreement with experimental results [18]. Then we extend the ability of this method to solve the 3D problem. Numerical results behind the obstacle, obtained for various Reynolds numbers, are also analyzed and discussed