A NUMERICAL STUDY OF THE MOTION OF DROPS IN COUETTE FLOW:(HIGH REYNOLDS NUMBERS) THE EFFECTS OF VISCOSITY RATIO

In this paper, the motion of two-dimensional deformable drops suspended in a linear shear flow at finite Reynolds numbers is studied numerically by a fronttracking method. The simulations are carried out for suspensions of 36 drops within each periodic domain, for an extended period of time up to Gt=341, where G is the shear rate. The effects of flow parameters such as the Reynolds number, the Weber number and the viscosity ratio on the rheological properties of suspensions are reported. Simulations show that at constant viscosity ratio and Weber number, the effective viscosity increases with the Reynolds number. It is also shown that suspensions of deformable drops exhibit a shear thinning behavior, but the shear thinning is reduced as the Reynolds number increases.

Keywords:

Couette flow , Drop , Deformation , Front-tracking , two-phase flow