Hydrodynamic dispersion in a single rock joint

This paper deals with the hydrodynamic dispersion of a contaminant in a single rock joint; the effects of molecular diffusion due to a concentration gradient are considered to be negligible relative to the hydrodynamic effects, and the surfaces of the rock joint are assumed to be geochemically stable. Both laminar and turbulent flow are treated, and the constitutive properties of the contaminant are assumed to be the same as those of the parent fluid. Within this framework and with a knowledge of the boundary condition at the origin, the time-dependent average concentration at any point within the joint can be found by using either (a) a Taylor series expansion or a polynomial approximation for this boundary condition, or (b) an incremental approach based on the principle of superposition. Experimental data are given to substantiate the acceptability of the assumptions employed.