Study of Polydisperse Particulate Systems with a ‘Direct-Forcing/Fictitious Domain’ Method

Abstract

Natural sediments responsible for the morphodynamic of the estuaries and coast are of different sizes and densities. Some are cohesive and some are non-cohesive. The transport in suspension and their sedimentation of such a polydisperse suspension are different than the ones for a monodisperse suspension. A fully resolved model based on the Direct-Forcing/Fictitious Domain method (DF/FD) was developed and applied to simulate settling of monodisperse particles in a water column. The behaviour of the suspension corresponds qualitatively to experimental results and average settling velocities follow a Richardson-Zaki type law. Then the model is applied to the sedimentation of suspension composed of particles of three diameters. The segregation of the bed is obtained naturally. The excess pore pressure is drawn and compared with the theory.