Fluctuations in fluid invasion into disordered media

TL;DR

This paper investigates the stochastic velocity fluctuations of interfaces moving through disordered media, revealing a geometry-dependent length scale in fluid invasion and comparing it to non-equilibrium depinning transitions.

Contribution

It introduces a new understanding of velocity fluctuations governed by geometry-dependent length scales in fluid invasion, linking conservation laws to universal scaling.

Findings

Velocity fluctuations follow universal scaling relations.

A geometry-dependent length scale influences fluid invasion dynamics.

Comparison with depinning transition statistics highlights different fluctuation behaviors.

Abstract

Interfaces moving in a disordered medium exhibit stochastic velocity fluctuations obeying universal scaling relations related to the presence or absence of conservation laws. For fluid invasion of porous media, we show that the fluctuations of the velocity are governed by a geometry-dependent length scale arising from fluid conservation. This result is compared to the statistics resulting from a non-equilibrium (depinning) transition between a moving interface and a stationary, pinned one.