Simulation of flow past a rotating circular cylinder near a plane wall

A two dimensional incompressible flow past a rotating circular cylinder near a plane wall at Re 200 is investigated by using the lattice Boltzmann equation (LBE). The effects of the gap between the cylinder and the wall, and tangential speed of the cylinder on the frequency of vortex shedding, and the lift and drag forces on the cylinder are quantified together with the flow patterns. With a fixed tangential speed of the cylinder, the flow behavior strongly depends on the normalized cylinder-wall gap h : H/D, where H and D are gap height and cylinder diameter, respectively. The flow is steady and behaves almost like a surface mounted object when h is small. With a moderate h, the flow is periodic and pairs of vortices with alternating signs develop due to strong interaction between the rotating cylinder and the wall. As h increases beyond certain value, the wall effect diminishes and the flow behaves almost as in an unbounded domain. Our simulation also validates the LBE method as a tool for direct numerical simulations for hydrodynamics. And we demonstrate that the LBE model with multiple-relaxation-time (MRT) is superior than the popular lattice Bhatnagar-Gross-Krook model in terms of numerical stability and in turn the efficiency.