RA-A: Free flow and porous-media flow interaction

Flow and transport processes in domains composed of a porous medium and an adjacent free-flow region appear in a wide range of industrial, bio-medical and environmental applications. Industrial applications range from flow in fuel cells to drying processes, while the interplay of distribution processes in blood vessels and in the surrounding tissue is a possible bio-medical application.

Applications in environmental systems include infiltration of overland flow during rainfall and groundwater contamination due to infiltrating pollutants as well as evaporation from soil. The example of evaporation from soil describes the huge variety of appearing challenges quite well: The evaporation rates and patterns affect the energy balance of terrestrial surfaces and drive a multitude of climatic processes. The prediction of evaporative drying rates from porous media remains a challenge due to the ambient conditions at the interface: radiation, humidity, temperature, air velocity, turbulence conditions.

Moreover, the internal porous-medium properties lead to abrupt transitions and rich fluid dynamics. The factors involved are coupled by the complex interactions between the porous medium and the free-flow system. Modelling such coupled systems while accounting for the respective processes in both domains is a challenging task, especially since many of these systems are dominated by multi-phase compositional flow.