InterPore2026

Direct Visualization of viscoelastic flow fields in 3D porous media using X-ray particle velocimetry

19 May 2026, 17:25

15m

Oral Presentation (MS14) Advanced Flow Physics in Specialized Porous Systems: Non-linear dynamics and finite-size effects MS14

Speaker

Parsa Damanshokouh (Ghent University)

Description

The flow of viscoelastic fluids such as polymeric solutions in porous media has a wide range of applications, spanning from green energy transition to biofluids and groundwater remediation. Such flows can give rise to viscoelastic turbulence in porous media, even at very small Reynolds numbers. Depending on the application, this chaotic behavior can be considered either an advantage, enhancing mobility or mixing, or a disadvantage, disrupting predicted flow paths or reducing apparent permeability. Most existing research on these complex flows relies on simplified experimental systems, often limited to two-dimensional microfluidic models [1], as it is challenging to measure flow fields in three-dimensional porous media. Such approaches hence do not fully capture the geometric complexity of natural three-dimensional porous media such as rocks and sediments. As a result, our understanding of the transition from viscous-dominated flow to chaotic behaviors associated with viscoelastic fluid flow in realistic porous structures has remained limited.
In this study, we present the first measurements of viscoelastic flow fields in optically opaque, 3D porous media. We employ state-of-the-art time-resolved X-ray micro-CT scans in combination with enhanced particle velocimetry algorithms [2], revealing complex responses of dilute polymeric flow in individual pores throughout time. This novel technique allows us to capture the onset of viscoelastic instabilities in three dimensions in correlation with geometrical parameters and fluid flow conditions. We investigate this in several porous materials with distinct pore geometries: glass bead packs with smooth pore walls (used as a baseline comparable with other studies), packings of obsidian shards with highly angular pore walls, and natural sand packs which represent an intermediate between these extremes. For the fluid, we use partially hydrolyzed polyacrylamide (HPAM) dissolved at different concentrations (300 and 500 ppm) in a glycerol-water mixture. Rheometry on these fluids showed that at targeted concentrations both fluids are shear thinning and exhibit viscoelastic responses.
Our results elucidate the impact of 3D pore geometries as well as fluid rheology and flow rate on 3D viscoelastic flow responses at the pore scale. For example, the sharp edges of obsidian shards introduce locally increased stresses, which can result in more pronounced viscoelastic instabilities at elevated Weissenberg numbers. Furthermore, we investigate the impact of viscoelasticity compared to purely shear-thinning rheologies at relatively low Weissenberg numbers. The novel pore-scale insights gained in these experiments enable us to explain flow responses at larger scales, e.g. apparent permeability variations, and hence contribute to better modeling of complex porous media flows related to energy and environment.