ABSTRACT
This chapter deals with the motion of a solid particle in a liquid. We assume that the characteristic dimension of the particle is small, so that the Reynolds number of the flow around it is small too. This situation is encountered in many industrial or natural situations involving flowing particle suspensions for which different problems arise: determination of the effective transport properties, stability and sedimentation. We first establish general relations between the particle velocity and the hydrodynamic resultant force which is exerted (whether it is a propulsion or a drag force). These relations are then specified for different particle shapes such as spheres, rods and helices. In a final part we show how the approach presented in this chapter can be used to study the propulsion of micro-organisms with applications in biology, physiology or the environment.
