Comparison of a micro-scale and a meso-scale model ...

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XVI International Conference on Computational Methods in Water Resources (CMWR-XVI) Ingeniørhuset

Comparison of a micro-scale and a meso-scale model concept for two-phase flow in fractured-porous media
Paper
Author:Song Pham Van <song.phamvan@wahyd.tu-berlin.de> (Department of Water Resources Management and Hydroinformatics, Institute of Civil Engineering, Technische Universität Berlin)
Reinhard Hinkelmann <reinhard.hinkelmann@wahyd.tu-berlin.de> (Department of Water Resources Management and Hydroinformatics, Institute of Civil Engineering, Technische Universität Berlin)
Presenter:Song Pham Van <song.phamvan@wahyd.tu-berlin.de> (Department of Water Resources Management and Hydroinformatics, Institute of Civil Engineering, Technische Universität Berlin)
Date: 2006-06-18     Track: Special Sessions     Session: Multiscale methods for flow in porous media
DOI:10.4122/1.1000000408
DOI:10.4122/1.1000000409

Two-phase flow processes in porous media occur in a wide variety of environmental engineering fields such as water-gas flow in coal mining areas, salt-water intrusion problems in coastal areas, seepage processes through dikes or water- infiltration processes in hillslopes. The description of two-phase flow in fractured porous media and macropores is a very challenging problem because of the heterogeneous structures, the very different process speeds and the multiples scales involved which all together lead to highly non-linear equations. In this paper, we will discuss and compare two different model concepts for two- phase flow in fractured-porous media which are implemented in the numerical simulator MUFTE-UG. MUFTE-UG stands for the Multiphase Flow Transport and Energy model and contains different physical model concepts and discretization techniques for multiphase flow in porous and fractured-porous media; UG is the abbreviation of Unstructured Grids, and this toolbox provides fast solves based on parallel adaptive multigrid methods. The so-called micro-scale model concept takes the fracture and the matrix into account as elements of the same dimension. Therefore, the mesh is highly resoluted in the fracture as well as in its close surroundings. The meso-scale model concept is based on the combined model approach, i.e. fractures are considered as elements of lower dimenision, for example as one-dimensional elements in a two-dimensional domain. Generally, the mesh resolution of the fracture-matrix space is coarser. For water infiltration via fracture and matrix, we will check whether and under which conditions we can find back the results of the micro-scale model concept in the meso-scale approach. A comparison with controlled laboratory experiments is envisaged. The comparison of the model concepts is of fundamental importance, as the results should be scaled up later to larger scales.