Levich Institute Seminar Announcement, 03/29/2016
Steinman Hall, Room #312
(Chemical Engineering Conference Room)
Professor Grae Worster
University of Cambridge (UK)
Department of Applied Mathematics and Theoretical Physics (DAMTP)
"Freezing of Soils and Colloidal Suspensions"
Saturated soils expand as they freeze, not because water expands as it freezes but because inter-molecular forces between ice and soil grains push the soil grains apart, which causes more water to be sucked into the region of freezing. In many circumstances, thick lenses of ice form that separate layers of consolidated, partially frozen soil. It is when these ice lenses melt that the consolidated soil collapses and potholes form - an all too common, undesirable feature of our winter- time roads. More positively, freezing of colloidal suspensions is being explored as a way of fabricating micro-porous materials such as artificial bone. In this talk, I shall describe the interplay between inter-molecular, disjoining forces and the pressures associated with fluid flow through the porous, partially frozen soil. New laboratory experiments on the freezing of colloidal suspensions will be presented that provide well characterised scenarios that can be modelled mathematically. A simple one- dimensional, mathematical model will be described that captures the observed phenomenology including consolidation of the colloidal suspension, the formation of partially frozen soil with ice in its pores, and the formation of periodic ice lenses in a system that is being forced at a constant rate.
BRIEF ACADEMIC/EMPLOYMENT HISTORY
I completed my PhD at the University of Cambridge, UK in 1983, was an Instructor in Applied Mathematics at MIT and an Assistant Professor in Applied Mathematics and Chemical Engineering at Northwestern University. I am currently Professor of Fluid Dynamics in the Department of Applied Mathematics and Theoretical Physics, University of Cambridge, and Editor of the Journal of Fluid Mechanics.
RECENT RESEARCH INTERESTS
Buoyancy-driven flows and phase change, particularly in situations where these two phenomena interact. In the context of climate change, I have combined mathematical modelling and laboratory experiments to understand and quantify the mechanisms affecting brine drainage from sea ice, the flow and stability of marine ice sheets and fundamentals of frost heave.