Numerical Investigation of Confined Flow Around Circular and Square Obstacle Using the Multiple Relaxation Time Lattice Boltzmann

Flow behavior can be changed by parameters such as fluid properties, geometry, and operating conditions. This paper presents a 2D numerical analysis of incompressible fluid flow in a channel with either a circular or square cylinder using the multiple relaxation time Lattice Boltzmann method (LBM-MRT). All simulations are performed at a fixed Reynolds number of Re = 100. A parabolic velocity profile is imposed at the inlet, while no-slip boundary conditions are adopted at the channel walls and obstacle surfaces. The numerical model is validated by comparing the mean drag coefficient with findings in the literature. Subsequently, the effects of obstacle shape, size, and position on the flow behavior and hydrodynamic forces are investigated. The effects of three obstacle sizes and three distinct positions are investigated for circular and square geometries under identical flow conditions. The results show that increasing the obstacle size modifies the flow and wake structure, and affects the drag and lift coefficients. Compared with the circular obstacle, the square obstacle creates stronger flow disturbances because of its sharp corners. The results also highlight the important effects of obstacle shape, size, and position on the flow characteristics and hydrodynamic coefficients.