Lattice Boltzmann Simulations of 2D Laminar Flows past Two Tandem Cylinders

We apply the lattice Boltzmann equation (LBE) with multiple-relaxation-time (MRT) collision model to simulate laminar flows in two-dimensions (2D). In order to simu-late flows in an unbounded domain with the LBE method, we need to address two issues: stretched non-uniform mesh and in-flow and out-flow boundary conditions. We use the interpolated grid stretching method to address the need of non-uniform mesh. We demonstrate that various in-flow and out-flow boundary conditions can be easily and consistently realized with the MRT-LBE. The MRT-LBE with non-uniform stretched grids is first validated with a number of test cases: the Poiseuille flow, the flow past a cylinder asymmetrically placed in a channel, and the flow past a cylinder in an unbounded domain. We use the LBE method to simulate the flow past two tandem cylinders in a unbounded domain with Re = 100. Our results agree well with existing ones. Through this work we demonstrate the effectiveness of the MRT-LBE method with grid stretching