Drying and percolation in spatially correlated porous media

TL;DR

This study investigates how small-scale correlations in porous media influence drying dynamics and invasion percolation behavior, revealing that local structure can significantly alter critical exponents and challenge universality.

Contribution

The paper combines experimental micro-models and numerical invasion percolation simulations to analyze the impact of spatial correlations on drying front dynamics and critical phenomena.

Findings

Correlations increase intermittency in drying dynamics.

A crossover in invasion behavior depends on correlation length.

Local structure affects critical exponents and universality.

Abstract

We study how the dynamics of a drying front propagating through a porous medium are affected by small-scale correlations in material properties. For this, we first present drying experiments in micro-fluidic micro-models of porous media. Here, the fluid pressures develop more intermittent dynamics as local correlations are added to the structure of the pore spaces. We also consider this problem numerically, using a model of invasion percolation with trapping, and find that there is a crossover in invasion behaviour associated with the length-scale of the disorder in the system. The critical exponents associated with large enough events are similar to the classic invasion percolation problem, whereas the addition of a finite correlation length significantly affects the exponent values of avalanches and bursts, up to some characteristic size. This implies that the even a weak local structure can interfere with the universality of invasion percolation phenomena.