%0 Book
%A Ippisch, Olaf
%D 2001
%F heidok:3220
%K Permafrostsoil physics , multiphase transport , permafrost , model , porous medium
%R 10.11588/heidok.00003220
%T Coupled Transport in Natural Porous Media (2. rev. Ed.)
%U https://archiv.ub.uni-heidelberg.de/volltextserver/3220/
%X As the interactions between transport processes are important for a number of interesting systems, a set of partial differential equations and appropriate parameter functions for the study of coupled water, heat, gas and solute transport was formulated and a state of the art computer model for the numerical solution of the equation system was created. A new phase pressure/partial pressure formulation for the coupled transport of liquid and gas phase was developed.  The model was used to simulate the water and energy dynamics of a permafrost soil. A good qualitative agreement was achieved. Differences between modeled and measured data could be explained with heterogeneity in combination with the model's sensitivity to a change in hydraulic parameters. Water vapor and solute transport had no effect on the simulation result but transport of liquid water proved to be an important heat transfer process near 0 °C.  The impact of the chosen parameterization and model on the simulation of a multistep outflow experiment was analyzed. Differences between a model based on Richards' equation and a twophase model only occurred when the Brooks-Corey parameterization was used. The results of the twophase model showed a retarded drainage and a hysteresis during imbibation which is in good agreement with experimental results.