Abstract. Yield stress materials (viscoplastic fluids) can be found anywhere in nature and in daily-use products. The main characteristic of these fluids is that they will not flow unless critical stress is exceeded, the so-called yield stress. Their behavior lies somewhere between liquids and solids. In this talk, I will present some constitutive models that are used to describe this behavior. I will also go through our understanding of how the solid-fluid transition takes place and propose a simple physical model to explain the phenomena. Towards the end of the talk, I will present experimental and numerical results of unsteady flow problems involving a viscoplastic fluid.

Bio. Dr Miguel Moyers Gonzalez is a Senior Lecturer in the School of Mathematics and Statistics of University of Canterbury, NZ. Previously he was a Lecturer in the Department of Mathematical Sciences at Durham University, UK. He spent two years in the Laboratory of Applied Mathematics in the University of Montreal as a CRM Postdoctoral Fellow. He did his MSc and PhD studies in the Department of Mathematics and the Institute of Applied Mathematics in UBC, Canada. His Doctoral Thesis was awarded the 2005 Cecil Graham Doctoral Dissertation Award from the Canadian Applied and Industrial Mathematics Society (CAIMS).

Miguel’s research field is the mathematical and computational modeling of problems in Continuum Mechanics. In broad terms, the problems Miguel focuses on involve the combination of physical understanding, i.e. of a particular application, coupled with both theoretical and computational techniques for partial differential equations and integral equations.