A numerical continuous model for the hydrodynamics of fluid particle systems

In order to understand the hydrodynamic interactions that can appear in a f luid particle motion, an original method based on the equations governing t he motion of two immiscible fluids has been developed. These momentum equat ions are solved for both the fluid and solid phases. The solid phase is ass umed to be a fluid phase with physical properties, such as its behaviour ca n be assimilated to that of pseudo-rigid particles. The only unknowns are t he velocity and the pressure defined in both phases. The unsteady two-dimen sional momentum equations are solved by using a staggered finite volume for mulation and a projection method. The transport of each particle is solved by using a second-order explicit scheme. The physical model and the numeric al method are presented, and the method is validated through experimental m easurements and numerical results concerning the flow around a circular cyl inder. Good agreement is observed in most cases. The method is then applied to study the trajectory of one settling particle initially off-centred bet ween two parallel walls and the corresponding wake effects. Different parti cle trajectories related to particulate Reynolds numbers are presented and commented. A two-body interaction problem is investigated too. This method allows the simulation of the transport of particles in a dilute suspension in reasonable time. One of the important features of this method is the com putational cost that scales linearly with the number of particles. Copyrigh t (C) 1999 John Wiley & Sons, Ltd.