Experimental and simulated solute transport in a partially-saturated, variable-aperture fracture

We compare solute transport experiments to simulations in a partially‐saturated, variable‐aperture fracture in measured fracture aperture and entrapped‐air geometry fields. The computational model tracks particles through a quasi‐three‐dimensional velocity field that is based on the two‐dimensional solution to the Reynolds equation. The model predicts 84% of the relative increase in dispersion caused by the entrapped phase, and reproduces the experimentally observed nonlinear velocity‐dependence of solute dispersion.