PurposeFor a homogeneous soil, the traditional laminar flow and well-known Taylor diffusion mechanism cannot interpret dispersivity (linear relationship between dispersion coefficient and pore-water velocity). The objective of this study was to propose a new mechanism and mathematical model based on fluid mechanics.MethodsDue to the roughness of the wall of a soil capillary tube, a new turbulent flow is proposed to be eddies at the wall and laminar flow at the main stream of a soil capillary tube. A new eddy dispersion mechanism is that the behavior of solute in the eddies follows random walks...
