Interazioni idrodinamiche nella sedimentazione di dispersioni colloidali

The aim of this thesis is to carry out a theorethical-computational study of the effect that hydrodynamic interactions have on the sedimentation process of a cluster of colloidal particles.The sedimentation of a cluster of particles is of fundamental importance in biological and industrial applications and, although it is relatively easy to study for one or two particles, for 3 or more particles the dynamics becomes extremely complex and not been fully understood. Here we will introduce the interactions between colloids mediated by the fluid within the Oseen approximation and will look at the dynamical trajectories of a set of 3-4 sedimenting particles, as a function of the initial conditions. Finally, by starting from a configuration in which the particles are within a cluster, he will estimate the cluster lifetime as a function of the initial conditions and number of particles.