Viscous and gravitational contributions to mixing during vertical brine transport in water‐saturated porous media

Abstract

The transport of fluids miscible with water arises in groundwater contamination and during remediation of the subsurface environment. For concentrated salt solutions, i.e., brines, the increased density and viscosity determine mixing processes between these fluids and ambient groundwater. Under downward flow conditions, gravitational and viscous forces work against each other to determine the interfacial mixing processes. Historically, mixing has been modeled as a dispersive process, as viscous fingering, and as a combination of both using approaches that were both analytical and numerical. A compilation of previously reported experimental data on vertical miscible displacements by fluids with significant density and viscosity contrasts reveals some agreement with a stability analysis presented by Hill (1952). Additional experimental data on one‐dimensional dispersion during downward displacement of concentrated salt solutions by freshwater and freshwater displacement by brines support the stability analysis and provides an empirical representation for dispersion coefficients as functions of a gravity number and a mobility ratio.

Genetic conservation and management of the California endemic, Torrey pine (Pinus torreyanaParry): Implications of genetic rescue in a genetically depauperate species

“…Santa Rosa Island on average receives slightly more annual precipitation (331 mm) than the Torrey Pines State Natural Reserve (245 mm); however, evapotranspiration levels on the island (1,042 mm) are greater than those of the mainland population (1,024 mm), based on results from ClimateWNA (Wang, Hamann, Spittlehouse, & Murdock, 2012). Empirical examination of tree rings from different tree species across the Channel Islands suggests that growth is tightly linked to evapotranspiration rates and developmental strategies, such as seasonal photosynthetic activity, may have evolved to persist under limited water availability (Fischer & Still, 2007; Williams, 2006). Consequently, increased cone size may provide greater control of evapotranspiration rates within the island population, selecting for increased water use efficiency.…”

Enhanced remedial amendment delivery to subsurface using shear thinning fluid and aqueous foam

“…This ratio is defined as the mobility of the displaced, or resident, phase over that of the displacing phase, where the mobility is equal to the effective permeability of each phase divided by the viscosity of that phase. The mobility ratio can be simplified as the ratio of the resident fluid viscosity, R , to the displacing fluid viscosity, D , when the flow is confined in a uniform porous medium [23][24][25].…”

Non-passive Transport of Volatile Organic Compounds Infiltrated from a Surface Disk Source

“…In addition, the experiments and simulations carried out by Gillham (1994, 1999), , , and Henry and Smith (2006) involved pure infiltration scenarios, unlike our simulations, which include infiltration and volatilization of the mixture. Flowers and Hunt (2007) studied the effect of density and viscosity on the mixing of brines and groundwater. They suggest that dispersion coefficients tend to decrease for infiltrating mixtures that are less dense and more viscous than the displaced water.…”