Transport of complex and active fluids in porous mediaa)

Complex and active fluids find broad applications in flows through porous materials. Nontrivial rheology can couple to porous microstructure leading to surprising flow patterns and associated transport properties in geophysical, biological, and industrial systems. Viscoelastic instabilities are highly sensitive to pore geometry and can give rise to chaotic velocity fluctuations. A number of recent studies have begun to untangle how the pore-scale geometry influences the sample-scale flow topology and the resulting dispersive transport properties of these complex systems. Beyond classical rheological properties, active colloids and swimming cells exhibit a range of unique properties, including reduced effective viscosity, collective motion, and random walks, that present novel challenges to understanding their mechanics and transport in porous media flows. This review article aims to provide a brief overview of essential, fundamental concepts followed by an in-depth summary of recent developments in this rapidly evolving field. The chosen topics are motivated by applications, and new opportunities for discovery are highlighted. (c) 2022 The Society of Rheology.

Automated summary

Complex and active fluids in flows through porous materials have broad applications and can exhibit surprising flow patterns and transport properties due to the coupling with porous microstructure. Recent studies have investigated how pore-scale geometry influences the flow topology and transport properties at the sample scale. Active colloids and swimming cells present unique challenges in understanding their mechanics and transport in porous media flows.