PHYSICAL MATHEMATICS SEMINAR TITLE: DYNAMICS OF VISCOPLASTIC FILMS SPEAKER: NEIL BALMFORTH Department of Mathematics Massachusetts Institute of Technology ABSTRACT: Many fluids possess extensive microstructure due to the interactions between, for example, suspended particles or crystals. This microstructure can become so extensive that it influences the macroscopic properties of the material, creating a yield stress and a flow-dependent viscosity -- two of the key properties of viscoplastic fluids. Many materials in chemical engineering are viscoplastic, and several industrial processes involve the spreading of relatively thin films. In geophysical fluid dynamics, shallow layers of mud and lava have also been modeled as viscoplastic films partly with the aim of understanding the initiation of catastrophic events. In this talk, I will describe recent efforts to explore the dynamics of viscoplastic films, focusing on the particular application to surges in mudflow. TUESDAY, OCTOBER 21, 2003, 2:30 pm, Building 2, Room 338 Refreshments will be served at 3:30 PM in Room 2-349 Massachusetts Institute of Technology, Department of Mathematics, Cambridge, MA 02139