Three-dimensional fluid flow and solute transport in rough-walled fractures

This thesis examines flow and transport through a single laboratory scale rock fracture, which is the necessary starting point for predicting flow and transport through large scale fractured rock systems. The primary objective was to develop a numerical model to simulate three-dimensional small-scale fluid flow within a single fracture using the Navier-Stokes (NS) equations. The fracture flow model was verified by comparing simulations to analytical and published results of fluid flow through parallel and sinusoidal plates. The flow model was applied to numerous synthetic or randomly generated rough-walled fractures, and the results clearly demonstrate for Reynolds numbers ( Re) above unity, that the inertial forces may significantly influence the internal flow field within a fracture and the bulk flow rate across a fracture. Conversely, these simulations demonstrated that inertial forces may be neglected when Re was below unity.; The secondary objective of this investigation was to develop a numerical model to simulate three-dimensional small-scale solute transport within a single fracture using the flow field determined by the NS flow model. To accomplish this task, the random walk particle method (RWPM) was employed. The fracture transport model was verified by comparing the simulation results to analytical solutions of solute transport through a set of parallel plates. Furthermore, the model simulations were compared to observations of solute breakthrough during tracer experiments on an actual rough-walled fracture, and a rough-walled transparent fracture replica. The model was successful in predicting the breakthrough curve for the actual fracture, and moderately successful for the transparent fracture replica.; By comparing the developed models to analytical solutions, simplified numerical simulations, and laboratory experiments, it was concluded that the models adequately describe fluid flow and contaminant transport through a single rough-walled fracture. Some examples of future applications of these models include: the comparison of the three-dimensional RWPM to the two-dimensional advection-dispersion equation for various synthetic fractures, high Reynolds number fluid flow and contaminant transport, and the dissolution of immiscible fluids trapped within a rough-walled fracture. (Abstract shortened by UMI.)...