Lattice-Boltzmann simulation of circular column coupled with square column in cross flow

Based on the single relaxation time lattice Boltzmann method, a numerical simulation model of fluid flow over two side-by-side columns is developed. One is a resting square column and the other is a circular cylinder which can rotate with a constant velocity. The calculation is carried out at a pitch ratios (S/D = 0.5, where S is the gap distance while D is the circular column diameter) at Reynolds number of 150. The effects of the curved boundary offset lattice links and the solid boundaries velocity is introduced into the model. Comparing the benchmark problem of fluid flow over a single column, the drag and lift forces (Cd, Cl) and the wake flow characteristics are studied to verify the model and investigate the interaction of the two columns. The results indicate that the interaction of the two columns has significant influence on dynamic characteristics of fluid flow over columns. The regular vortex shedding comes into irregular. The Cd and Cl increase under the effect of the interaction. Furthermore, with the rotating velocity is increased, the fluctuation of Cd and Cl becomes more serious.