Flow-induced channelization in a porous medium

TL;DR

This paper develops a multiphase theoretical model explaining how fluid flow causes erosion in porous media, leading to channel formation, with results showing the influence of erosion threshold heterogeneity on pattern development.

Contribution

It introduces a novel multiphase model coupling porosity evolution with grain mobility to explain flow-induced channelization in porous media.

Findings

Channels form due to erosion when flow stress exceeds a threshold.

Heterogeneity in erosion threshold influences pattern morphology.

Numerical solutions demonstrate the dynamics of channel growth.

Abstract

We propose a theory for erosional channelization induced by fluid flow in a saturated granular porous medium. When the local fluid flow-induced stress is larger than a critical threshold, grains are dislodged and carried away so that the porosity of the medium is altered by erosion. This in turn affects the local hydraulic conductivity and pressure in the medium and results in the growth and development of channels that preferentially conduct the flow. Our multiphase model involves a dynamical porosity field that evolves along with the volume fraction of the mobile and immobile grains in response to fluid flow that couples the spatiotemporal dynamics of the three phases. Numerical solutions of the resulting initial boundary value problem show how channels form in porous media and highlights how heterogeneity in the erosion threshold dictates the form of the patterns and thus the ability to control them.