Rheological modelling of dense granular materials and suspensions
Prof Jin Sun (University of Glasgow)
Thursday 9th November 14:00-15:00 Maths 311B/ZOOM (ID: 881 3204 9167)
Granular materials are encountered ubiquitously in nature and industry, as in geomaterials, such as sands and sediments; and found in products ranging from cement to paints, foods and pharmaceuticals. Predicting their flow behaviour under general conditions, such as in landslides and in manufacturing processes, is still an open question and grand challenge, largely because of the lack of a general constitutive model(s). There is therefore no equation in analogy to the Navier-Stokes equation for water to describe the dynamics of granular flows.
In this presentation, I will first give an overview of my group’s work on modelling the flow behaviour of dry granular materials and suspensions at high solid concentrations under simple (rheometic) conditions. I will show that we can characterise a wide range of steady granular flows according to their solid volume fractions and deformation rates. Their asymptotic behaviour and the transitions between the different asymptotes can be described by a simple model after properly scaling of the stress and the deformation rate.
I will then demonstrate two cases where we worked with our collaborators in Mathematics to either apply the model to practical problems or find new solutions. For the former, we discovered new scaling relationships to channel flows; and for the latter, we obtained new formula for a classical lubrication flow problem.
Finally, I will outline some problems that we been working on and could be of potential interest to our colleagues in Mathematics.