Prediction of the low-velocity distribution from the pore structure in simple porous media


Title

Prediction of the low-velocity distribution from the pore structure in simple porous media

Publication Type
Journal Article
Year of Publication
2017
Journal
Physical Review Fluids
Issue
12
Date Published
Jan-12-2017
Publication Language
eng
Citation Key
3052
Abstract

The macroscopic properties of fluid flow and transport through porous media are a direct consequence of the underlying pore structure. However, precise relations that characterize flow and transport from the statistics of pore-scale disorder have remained elusive. Here we investigate the relationship between pore structure and the resulting fluid flow and asymptotic transport behavior in two-dimensional geometries of nonoverlapping circular posts. We derive an analytical relationship between the pore throat size distribution f λ ∼ λ − β and the distribution of the low fluid velocities f u ∼ u − β / 2 , based on a conceptual model of porelets (the flow established within each pore throat, here a Hagen-Poiseuille flow). Our model allows us to make predictions, within a continuous-time random-walk framework, for the asymptotic statistics of the spreading of fluid particles along their own trajectories. These predictions are confirmed by high-fidelity simulations of Stokes flow and advective transport. The proposed framework can be extended to other configurations which can be represented as a collection of known flow distributions.

Short Title
Phys. Rev. Fluids