Physical Chemistry Seminar: Measurements and modeling of anomalous transport and diffusion in natural geological media

Zoom: https://tau-ac-il.zoom.us/j/83828475939?pwd=IDFj3FakIb8lEMPCAtya8O92tFGplZ.1

Abstract:

Chemical transport in a biased velocity field plays a key role in naturally heterogeneous geological media, across scales from soil and rock pores to aquifers. Similarly, even purely diffusion-controlled chemical transport of tracers in rock formations plays a critical role in many dynamic processes that affect water chemistry and properties of the host domain. While it is common to expect that “the shortest path between two points is a straight line”, this is, invariably, not the case for water and chemical transport in soils and aquifers. Indeed, complex flow pathways often result in surprisingly fast, early-time arrivals of pollutants, as well as anomalously (and often annoyingly!) long-time delays. Moreover, when chemicals are reactive, groundwater systems can be altered by changes in solution chemistry and/or by a wide variety of chemical transformations such as precipitation and dissolution, with feedbacks that directly affect the flow and transport regime. The principal challenge in modeling advectively-driven and diffusion-controlled chemical transport is to account for the subtle effects of fluctuations in the pore space, flow field and species concentrations; critically, spatial or temporal averaging suppresses these effects. Moreover, modeling efforts must be grounded and tested against laboratory experiments and field measurements. We focus on the integration of these aspects, considering case studies in different frameworks. 

Seminar Organizer: Dr. Guy Cohen