Validation of Numerical Simulation of Fluid Flow Through Rough Rock Fractures Using Physical Modeling Based on 3D Printing

Accurate prediction of fluid transport th Rough Fracture d rocks is critical for groundwater management, hydrocarbon recovery, geothermal energy extraction, and subsurface waste isolation. Classical cubic‑law formulations fail when aperture variability and surface asperities dominate flow resistance, necessitating full Navier–Stokes modelling. Such models, however, require high‑quality experimental data for calibration and validation. Conventional casting or engraving cannot reproduce field‑scale roughness repeatably. This research addresses these challenges by combining precise additive manufacturing of fracture geometries with a pressure‑controlled permeameter, delivering reproducible datasets for numerical verification and future parametric studies. Surface topographies representing JRC 0, 10 and 20 were generated in CAD, respecting a 54 mm diameter and 110 mm length to fit a Hoek triaxial cell. The halves were printed from rigid photopolymer, sealed, water‑saturated, and assembled. A perforated 3D‑printed distributor ensured uniform inflow. Upstream head levels produced inlet pressures of 195, 293, 391 and 489 Pa; lateral confinement of 1–2 bar prevented side leakage. Outflow was weighed at one‑minute intervals until steady conditions were reached. Numerical meshes employed hexahedral elements refined near asperities. Incompressible, laminar Navier–Stokes equations were solved with a coupled pressure–velocity algorithm; convergence was accepted at residuals< 10⁻ ⁶. Discharge increased linearly with inlet pressure for every roughness, yet absolute flow rates decreased as JRC rose. At 195 Pa, measured flow …