Lift-off of a single particle in Newtonian and viscoelastic fluids by direct numerical simulation. (Q2743719)

The object is the lift-off to equilibrium of a solid particle, heavier than Newtonian or viscoelastic fluid in motion, in different channels. The study is numerical, based on the corresponding equations of motion. In the introductory part, the authors present the history of the problem, with contributions of different authors who worked in the area, useful for a good understanding of the problem and for the establishment of reference points in their comments and comparisons. The study begins with the presentation of governing equations, with a discussion of lift solid-liquid flow models, and with an exposition of numerical method used for the solution of the corresponding boundary value problems. There follows a discussion about the lift force on a particle in an unbounded, linear shear flow, and an analysis of a single particle in plane Poiseuille flow of Newtonian fluid, taking into account the pressure and shear of the flow. A great attention is given to the bifurcations of equilibrium solution appearing in the particle lift-off problem. The study ends with the analysis of the problem for Oldroyd-B fluid.