title: AIR-WATER INTERFACIAL AREA AND CAPILLARY PRESSURE: POROUS-MEDIUM EXTURE EFFECTS AND AN EMPIRICAL FUNCTION.
abstract: The relationship between air-water interfacial area and capillary pressure under higher water-content conditions is investigated for four natural porous media. The results show that the magnitude of the air-water interfacial area increases with increasing capillary pressure, consistent with the decrease in water saturation. The maximum observed air-water interfacial areas are dependent upon the magnitude of residual water saturation, which itself is condition dependent. The more well-sorted porous medium exhibited a greater rate of change of air-water interfacial area with capillary pressure than the more poorly-sorted porous media. The observed relationship between air-water interfacial area and capillary pressure was quantified by coupling an empirical equation describing the air-water interfacial area vs. water saturation relationship with the van Genuchten equation relating water saturation and capillary pressure. This equation produced reasonable simulations of the measured data.
authors.affiliation: School of Environment, Beijing Normal University, Key Laboratory of Water and Sediment Sciences of Ministry of Education, Beijing, 100875, China.
authors.forename: Sheng
authors.initials: S
authors.lastname: Peng
authors.forename: Mark L
authors.initials: ML
authors.lastname: Brusseau