Data Repository for Coupled density and inertia effects on solute trapping at fracture intersections: multiscale experiments and pore-scale simulations

Abstract

Density-driven flow and fluid inertia jointly influence solute transport in fracture networks, with broad implications for hydrogeological and subsurface engineering systems. While their individual effects are well recognized, their combined impact remains underexplored. This study integrates pore-to-network-scale visualization experiments and numerical simulations to investigate the effects of their interplay on solute transport at fracture intersections. At the network scale, 3D flume experiments revealed localized tracer trapping near intersections, driven by density-induced convection and inertia-induced vortices. At the intersection scale, millifluidic experiments and pore-scale simulations elucidated how density contrast, flow imbalance, and fluid inertia govern such solute trapping. Maximum trapping occurs when bottom fracture flow rate is 10% higher, which maximizes mass entry and limits loss. This imbalance promotes vortex retention and prolonged solute residence, producing breakthrough curve tailing. Simulations in rough-walled fractures confirmed these dynamics. The results underscore the critical role of pore-scale processes in governing network-scale transport.