ABSTRACT
This chapter provides the reader with an overview of the knowledge concerning the physics and rheology of suspensions of rigid particles. Suspensions of rigid particles in low Reynolds number flows are ubiquitous in industry or natural flows to mention but a few. The chapter addresses rigid spheres, which have been the subject of most studies on migration and segregation. Dense suspensions of rigid particles are a complex physical domain which has significantly progressed through experimental data and numerical simulations. The knowledge of suspensions of rigid particles is a prerequisite before moving to non-rigid particles. Actual contacts generally involve friction between particles and friction forces are found to strongly affect suspension dynamics, structure and rheology. There are however some additional specificities in blood flows, notably linked to the deformability of particles which can alter the hydrodynamic interactions.
