Non-Newtonian power-law fluid flow over obstacles embedded inside a cavity

Abstract

In this study, the flow of non-Newtonian fluid inside the lid-driven cavity with obstacle(s) is examined. The behavior of the fluid is described by the Ostwald-de Waele or power-law model. The lattice Boltzmann method (LBM) with a multiple-relaxation-time (MRT) collision model is employed to simulate complex fluid flows around the circular and square obstacles embedded inside a cavity. The stability of the present MRT-LBM algorithm in terms of so-called, cell-Reynolds number is investigated. The physics of flow structure and examinations of streamlines and vorticity contours are carried out for power-law as well as Newtonian fluids. For a single obstacle, the effects of various parameters such as Reynolds number (with respect to lid-dimension), obstacle size, power-law index, and shape of the obstacle on the flow characteristics and vortex formation are investigated. Furthermore, the effect of two square obstacles arranged in side-by-side and tandem manners inside the cavity is analyzed. Finally, the complex fluid flow over the multiple square obstacles embedded inside the cavity as a porous block for two blockage ratios is examined.