Force-coupling Method Research Articles

Incorporation of lubrication effects into the force-coupling method for particulate two-phase flow

We investigate the performance of the force-coupling method (FCM) for particulate flow at microscales. In this work, we restrict attention to flows where we may neglect fluid inertia (Stokes flows), particle inertia and Brownian motion. The FCM performs well when distances between solid boundaries are sufficiently large, however it does not capture the local effects of viscous lubrication forces for small gap widths. To improve the results, we develop a parameterization of the lubrication forces for inclusion in the model. This is based on exact results for isolated pairs of particles and single particle–wall configurations. The correction is imposed through the addition of a lubrication barrier force on affected particles. The parameterization is tested for several cases, illustrating both the improvements possible and the limitations.

Force-coupling method for particulate two-phase flow: Stokes flow

In this paper we describe a force-coupling method for particle dynamics in fluid flows. The general principles of the model are described and it is tested on three different Stokes flow problems; a single isolated sphere, a pair of otherwise isolated spheres, and a single sphere in a channel. For sphere to sphere or sphere to wall distances larger than 1/4 of the sphere radius the force-coupling results compared well with analytical and accurate numerical values. For smaller distances the results agree qualitatively, but lubrication effects are not included and this leads to a quantitative discrepancy.

Experimental verification of the force coupling method for particulate flows

A force coupling method for computing particulate flows is verified by comparison with experiments. The force coupling method and the experimental method are briefly described. In the comparison three examples are considered: a single particle rising in an inclined channel, two particles rising in a vertical channel and three particles rising in a vertical channel. It is shown that for the particle Reynolds numbers considered in this paper ( Re p<15) the force coupling method provides qualitatively and quantitatively good results. Consequently, the method is an attractive alternative to direct methods for simulations of particulate flows.