Wed May 11th 2022 16:00 – 17:00 ZH286 | Seminar | Structures, fluxes and the role of layering in strong porous convection Duncan Hewitt |
Details:Vigorous (high Rayleigh number) convection in fluid-saturated porous media is important in numerous geophysical settings, perhaps most pertinently with respect to the long-term stability of geologically sequestered carbon dioxide. Natural rock formations are typically highly heterogeneous; here we explore the impact of thin horizontal layering, which is a characteristic form of such heterogeneity in sedimentary formations, with the aid of numerical simulations and theory. After discussing the remarkable columnar structures that are a ubiquitous feature of strong porous convection, we explore the spreading and evolution of both an isolated buoyant plume and a distributed buoyant source in the presence of thin low-permeability baffles or layers. These layers are characterised by their impedance to flow, which controls the degree to which they disrupt the convective structures and fluxes. When the impedance is high, the layers have a very strong influence on the flow and this disruption can be dramatic. Some physical implications will be briefly discussed. |