Issues in flow and transport in heterogeneous porous media

Abstract

This invited lecture enumerates various categories of flow and transport in heterogeneous media with particular reference to this Symposium. Specific attention is given to five topics within these categories. (1) We explore the compounding of spatially variable local permeability K to produce an apparent permeability K* on a scale large compared with that of variation of K. An inverse method generates and analyzes flow systems with K spatially periodic in two and three dimensions. (2) Physical arguments indicate that apparent hydraulic properties of an unsaturated composite medium may not represent any conceivable mean of the properties of the component media. (3) Conventionally, buried holes are thought to stay empty during generally unsaturated soil-water flow. The hole, however, acts as an obstacle to flow so that water may seep through it. The larger the hole the more likely this will happen. (4) Dispersion in heterogeneous porous systems with no maximum scale of variation is explored using a Lagrangian mode of analysis. (5) Comments are offered on ‘geostatistics’ and its application to heterogeneous soils and aquifers.