We are interested in the flow and dynamics of complex fluids, such as dry granular materials, particle-fluid suspensions and collections of swimming microorganisms. Understanding the behaviour of these materials is of tremendous practical benefit, as they are processed or transported in large quantities in many industries, as much as it is a scientific challenge.

An important aspect of many of these materials is their complex kinematic and rheological response. The image at the right is a good example: it shows solid-like regions coexisting with fluid-like regions in the flow of glass beads through a bin. This is a generic feature of dry granular materials. Apart from complex rheology, most complex fluids also exhibit interesting dynamics, such as spontaneous segregation, stratification and phase change. The image at the lower-right is an example of shear-induced segregation of particles in a suspension of small particles in a viscous fluid.

Many features of such complex fluids are due to the presence of one or more internal variables that identify the microstructure. Identifying these variables and connecting them to the macroscopic behaviour is one of the main challenges. Our investigations are a combination of theoretical analysis, experiments and computation.