Abstract
Obtaining a reliable description of the transport of particles inside a fluid/gas is a critical problem regarding many applications: sedimentations, sprays, colloids [BB88]…. To predict the time-evolution of fluid+particle systems, a classical model consists in coupling partial differential equations (such as the Navier Stokes equations) to describe the fluid and Newton laws for the rigid particles. One obtains then a fully-coupled system as the fluid imposes the particle motion via the application of forces while the particles act on the fluid behavior by prescribing its domain and its velocity at fluid/particle interfaces. Consequently, such systems have been widely studied under suitable simplifying assumptions: reduced models for the fluid, simplifying assumptions on the solid features (simple shapes, constant densities) [SMT10]. One aim of this thesis is to measure how important it is to know the particle properties (shape, density) to make solution of those systems reliable. First a simple case (one almost-spherical particle in a Stokes fluid) will be studied. More complete models can be tackled afterwards.