PHYSICAL MATHEMATICS SEMINAR TITLE: RIPENING OF POROUS MEDIA SPEAKER: BENNY DAVIDOVITCH POST-DOCTORAL RESEARCHER EXXONMOBIL RESEARCH AND ENGINEERING ABSTRACT: When solid grains are put in a saturated solution they undergo a coarsening process in the course of which one big chunk is formed. This general phase-separation phenomenon is known as "Ostwald ripening". Limiting cases of the ripening process, when the volume fraction of the solid grains in the liquid is either very small (Lifshitz-Slyozov theory) or close to 1 (grain growth, foams), are governed by scaling laws and were studied extensively since the 1950's. In this talk I will focus on the intermediate case, where the volume fraction of the solid grains is relatively high (0.3-0.8), and both phases might be connected. This situation is typical for sedimentary porous media, especially oil and water reservoirs, whose coarsening process occurs over geological time scales. I will show that in this case the phase space of possible morphologies contains many unstable equilibrium states that can be considered as hyperbolic . fixed points of the dynamics. These fixed points are surfaces of constant mean curvature (CMC) he morphology and the dynamics of the system will be described by characterizing these configurations using tools from differential geometry and linear stability analysis. If time allows, I will discuss briefly a preliminary experimental work on the subject. TUESDAY, FEBRUARY 11, 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