Numerical simulation of particle sedimentation in shear-thinning fluids with a fictitious domain method. (English) Zbl 1195.76412

Yu, Zhaosheng; Wachs, Anthony; Peysson, Yannick

J. Non-Newton. Fluid Mech. 136, No. 2-3, 126-139 (2006).

Summary: In this study, the aggregation of particles settling in a shear-thinning fluid is numerically investigated with the distributed-Lagrange-multiplier based fictitious domain (DLM/FD) method. The collocation-element method and a fractional-step scheme based on keeping the Lagrange multiplier at the previous time level in the momentum equations are adopted to discretize the Lagrange multiplier. The lubrication force correction is implemented in the code as a collision strategy. We employ a thixotropic model to account for the time effect of shear-thinning. The results confirm that the memory of shear-thinning is responsible for the aggregation of two end-to-end settling particles, and indicate that the elasticity of the fluid, though may be very weak, seems necessary for the randomly distributed particles to aggregate into stable clusters or columns.

MSC:

76T20	Suspensions
76A05	Non-Newtonian fluids
76M25	Other numerical methods (fluid mechanics) (MSC2010)

Keywords:

numerical simulation; particulate flows; fictitious domain method; Lagrange multipliers; shear-thinning fluids; thixotropy; sedimentation; aggregation