Lattice Boltzmann Simulation Of Non-Newtonian Fluids In A Two Dimensional Square Cavity

In recent years, Lattice Boltzmann method (LBM) is the rapid development of numerical simulation method of fluids. Compared with traditional methods, this method has a lot of advantages, such as the simplicity of program, high efficiency of computation, natural parallelism which is a strong tool to simulate the complex flows. Also application field is very wide, such as: porous media, multiphase flow, turbulence, blood flow and so on. While there is close relationship between non-Newtonian fluids and our poduction and living , such as human body blood, lymphatic fluid and liquid of fluid, capsule, printing ink, asphalt sand, food additives, emulsion etc. Thus further study of non-newtonian fluid has great practical value. We know, there are a variety of fluid numerical simulation method for research, but the method using lattice Boltzmann for non-newtonian fluid problem hasn't caused wide spread concern.In this paper with D2Q9 model to simulate a generalized non-Newtonian fluid- Power-law fluids, we mainly used to study and analysis different types of flow phenomena among Newtonian fluids and shear thinning fluids and shear thickening fluids. Firstly, selecting a range of Reynolds number from 100 to 5000. Then we can compare and analysis flow phenomena of shear thinning fluids and shear thickening fluids when Reynolds number increases. We find the phenomena appeared in the cavity that becomes more and more complex. The central location of first-primary vortex is more and more close to the cavity center. Various vortex becomes strenger and the number of the vortex is also increased. Secondly, selecting a range of different index n from 0.25 to 1.75. As n increases, then we can compare and analysis some flow phenomena when the Reynolds number is constant.At this time,we can know Fluid viscosity increases when n increases. New phenomena appeared in the cavity that becomes more and more complex, various vortex becomes strenger and the number of the vortex is also increased. The center line velocity component also becomes more complex. with the change of n .