The dynamics of granular-fluid mixtures

Flows of granular-fluid mixtures occur widely in industrial processes and in daily life. Such mixtures are often polydisperse, containing both large particles that behave as a granular flow, and small particles that are suspended within the fluid. Predicting the rheology of these mixtures remains a major scientific challenge.
The objective of this project is to provide a new mathematical description of such mixtures, focusing on the how the suspension of particles by the fluid influences the formation of a static (non-shearing) layer of grains near the base of the flow. This will be achieved by constructing mathematical models within the framework of mixture theory, specifically accounting for the evolving fluid pressure as particles settle due to gravity. Asymptotic analysis will be used to provide a leading-order simplified model for mixtures with a high proportion of solid particles, with the aim of identifying the fundamental underlying mechanisms that govern the flow of these complex fluids.