Thu, 12 Feb 2015

16:00 - 17:00
L3

Convection of a reactive solute in a porous medium

Oliver Jensen
(Manchester)
Abstract

Abstract: Motivated loosely by the problem of carbon sequestration in underground aquifers, I will describe computations and analysis of one-sided two-dimensional convection of a solute in a fluid-saturated porous medium, focusing on the case in which the solute decays via a chemical reaction.   Scaling properties of the flow at high Rayleigh number are established and rationalized through an asymptotic model, that addresses the transient stability of a near-surface boundary layer and the structure of slender plumes that form beneath.  The boundary layer is shown to restrict the rate of solute transport to deep domains.  Knowledge of the plume structure enables slow erosion of the substrate of the reaction to be described in terms of a simplified free boundary problem.

Co-authors: KA Cliffe, H Power, DS Riley, TJ Ward

 

Thu, 22 Jan 2015

16:00 - 17:00
L3

Fingers and Flowers: Flow, transport, and deformation in porous materials

Chris MacMinn
(Oxford Engineering)
Abstract
Coupling across scales is often particularly strong in porous rocks,
soils, and sediments, where small-scale physical mechanisms such as
capillarity, erosion, and reaction can play an important role in
phenomena at much larger scales. Here, I will present two striking
examples of this coupling: (1) carbon sequestration, where storage
security relies on the action of millimeter-scale trapping mechanisms
to immobilise kilometer-scale plumes of buoyant carbon dioxide in the
subsurface, and (2) fluid injection into a granular solid, where
macroscopic poromechanics drive grain-scale deformation and failure.
I will show how we derive physical insight into the behaviour of these
complex systems with an effective combination of theoretical models,
numerical simulations, and laboratory experiments.

Jacqueline Anne Stedall (4 August 1950–27 September 2014)

Jackie Stedall came to Oxford in October 2000 as Clifford-Norton Student in the History of Science at Queen’s College. She held degrees of BA (later MA) in Mathematics from Cambridge University (1972), MSc in Statistics from the University of Kent (1973), and PhD in History of Mathematics from the Open University (2000). She also had a PGCE in Mathematics (Bristol Polytechnic 1991).

Mathematical Institute launches new website

The Mathematical Institute is pleased to announce the launch of its new website. The new website has been reworked from the ground up to be modern, flexible, engaging and inviting to current and future mathematicians and friends. A collaboration with William Joseph produced an initial design which was then developed and implemented in-house and, being based on modern technologies, is compatible with mobile devices.

Searches for small-scale anisotropies from neutrino point sources with three years of IceCube data
 Sarkar, S Astroparticle Physics volume 66 39-52 (17 Jan 2015)
Development of a general analysis and unfolding scheme and its application to measure the energy spectrum of atmospheric neutrinos with IceCube
 Sarkar, S European Physical Journal C volume C75 issue 3 116-116 (11 Mar 2015)
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