ABSTRACT
In this chapter we consider the flow of deformable particles suspended inside a liquid. The typical case is that of an emulsion of two immiscible liquids (oil in water or air in water, for example). The objective is to compute the motion and the eventual deformation of the droplets or bubbles as they move in the fluid and are subjected to hydrodynamic forces. This eventually leads to the determination of the velocity of phase separation and to the effective transport properties of such two-phase systems. Obviously the problem is complicated by the presence of a deformable interface of unknown geometry on which important boundary conditions are expressed. Different techniques are available to solve the Stokes equations in this case:
• For axisymmetric situations, spherical coordinates and a stream function can be used.
