Motivation

Porous media are encountered in many man-made as well as natural systems. Many industrial processes involve porous media flows. Some examples are processes in fuel cells, paper-pulp drying, food production and safety, filtration, concrete, ceramics, moisture absorbents, textiles, paint drying, polymer composites, and detergent tablets. The most well-known natural porous media involving multiphase flow and transport are soils, aquifers, and reservoirs. But such processes also occur in biological tissues and plants. Recently, there has been growing interest in the biomechanics of porous tissues, engineered tissues, and in-tissue drug delivery.

The common practice in modelling flow and transport in complex biological and industrial porous media has been to employ the concepts, models, and algorithms developed in the geosciences. However, biological and industrial porous media are significantly more complex than soils and reservoirs, and flow and transport processes occur in completely different regimes. Some major examples are as follows.

• Constitutive relations (e.g. capillary pressure curve) for soils and rocks are obtained under equilibrium conditions whereas many industrial flows are very fast and far from equilibrium.
• Porous media in the geosciences and biosciences are usually hydrophilic (exceptions are found in reservoir engineering and cellular membranes); in industrial processes, they can be completely or partially hydrophobic. Also, wettability changes are more common in many industrial porous media.
• Chemical reactions in the geosciences are usually slow and do not influence flow in the short term (although many exceptions are found in pollution and remediation processes and enhanced recovery techniques). This is often not the case in certain industrial processes (e.g. fuel cells, filtration, detergent tablets, food processing).
• Deformations in most biological and industrial porous media are fast and/or large and affect flows significantly. As a result, multiphysics and coupled phenomena are often more essential in such complex porous media.
• In complex porous media, we may encounter a variety of porous structures (granular, fibrous, foamy, layered, fractured etc.), length scales (nano-, micro-, and macroscales), different fluids (gaseous, liquid, gelatinous, supercritical), and a very wide range of porosity values (1 to 90%) that may change significantly in time and space. Furthermore, extremes such as very small pore sizes, high Reynolds numbers, and high temperatures may be encountered.

So there is a clear need to develop theories, models, and measurement techniques specifically applicable to complex porous media. Currently, there is no formal common platform for researchers in this extremely important area of porous media research. As a result, researchers in the various industrial systems mentioned above are often unaware of each other’s activities and sometimes the wheel is reinvented repeatedly. It is time to establish an international society to act as a platform for researchers active in modelling flow and transport in complex porous media.