Landesgraduiertenförderung: Modeling and analysis of coupled porous-medium and free flow with application to evaporation processes

Flow and transport processes in domains composed of a porous medium and an adjacent free-flow region appear in a wide range of industrial, environmental and medical applications. Our focus is on evaporation from unsaturated soils under influence of a turbulent free flow. An appropriate modeling of the water distribution and fluxes within the unsaturated zone is required for predicting vapor and energy exchanges between the soil and the atmosphere, and vice versa. Currently, fully describing water fluxes, flow pathways and water distribution influenced by and coupled to turbulent flow processes remains challenging. A turbulent, free, one-phase (gaseous) flow in the atmosphere and a flow in the soil, which might be a two-phase (gaseous and liquid) flow, with different dominating physical processes, are coupled. One important aspect of the interface is that the free and porous-medium flow are coupled there. Another important aspect is that the characteristics of the free flow can be altered by surface roughness or convective net flow through the porous medium, which can change the exchange processes noticeably.

The objective of this research project is to develop a physical and mathematical model using comprehensive computational analyses to acquire coupling concepts for free and porous-medium flow and insight into the influence of surface roughness on flow and mass exchange across the soil surface. The development of a coupled free and porous-medium flow model will, together with an examination of surface-roughness influences, lead to a deeper understanding of flow and mass exchange across the surfaces of porous media.

Prof. Dr.-Ing. Rainer Helmig

Melanie Lipp (M.Sc.)

LH2

10/2017 - 12/2020

Landesgraduiertenförderung