ABSTRACT
Fluids are large-scale aggregations of molecules whose interactions at the molecular scale lead to emergent behaviors of the fl uid at the macroscopic scale. Potter and Wiggert (1991) defi ne fl uids as “those liquids and gases that move under the infl uence of shear stress, no matter how small that shear stress may be” (italics in the original). In simpler terms, when we apply a force that moves molecules in one part of a fl uid, intermolecular cohesion transmits that motion to other molecules in the fl uid. The fl uids of interest in remediation hydraulics may be liquid, gaseous or mixtures of liquids, gases and solid particles. We also encounter polymers and other specialty fl uids in remediation hydraulics. It is the fundamental physical-chemical properties that determine how any fl uid will interact with the solid phase of an aquifer or with other, dissimilar fl uids.
