Quantitative links between porous media structures and flow behavior across scales

摘要

"With four parameters I can fit an elephant and with five I can make him wiggle his trunk." This citation of the famous mathematician John von Neumann [1] brings to the point why modeling of flow and transport processes in the vadose zone is such a difficult task. By inverse fitting of model parameters it is often possible to reproduce results that are very close to an experimental observation. It is, however, questionable if these parameters can be used for another flow or transport problem than the one they have been fitted for and if they can be used for a soil, considering that they are usually measured for a rather small sample. Improving the predictive power of models is strongly related to the understanding and interpretation of the relation between model parameters and the structural properties of the porous medium.