Numerical Simulation of Non-Newtonian Fluid over a Stationary Circular Cylinder in the Channel

In the current study, the non-Newtonian fluid over a stationary circular cylinder has been simulated using the lattice Boltzmann method. The regime of 2D and unsteady flow (Re=100) for different non-newotonian power-law indices (0.4≤n≤1.8) and four different aspect ratios of 2, 4, 6 and 8 has been investigated. The power-law model was used for describing the non-Newtonian behavior of the fluid. The results have been compared with previous experimental and numerical results. The effects of the power– law index and aspect ratio on the vorticity contour, average drag coefficient, fluctuations of lift coefficient and time averaged of pressure coefficient have been studied in detail. The results show that the steady or unsteady fluid behavior depend on power-law index and aspect ratio. Generally, the average of drag coefficient deacreases by increasing aspect ratio at fixed power-law index. For all considered aspect ratio, except B=2, the average of drag coefficient increases when the fluid behavior changes from shear thining to shear-thickening.