A 2.75 D Finite Element Model of 3D Fracture Network Systems

Proceedings, 11th International Meshing Roundtable, Sandia National Laboratories, pp.161-168, September 15-18 2002

MESHING
RESEARCH
CORNER

11th International Meshing Roundtable
Ithaca, New York, USA
September 15-18, 2002

Sylvia Moenickes, Rene Kaiser, Werner Zielke
Institute for Fluid Mechanics, ISEB,
Universitat Hannover, Hannover, Germany.
moenickes@hydromech.uni-hannover.de

Takeo Taniguchi
Faculty of Environmental Science and Technology,
Okayama University, Okayama, Japan

Abstract
The simulation of fluid flow and heat transport in fracture network systems requires new grid generation techniques. A fractured subsurface domain may be regarded as a convex 3 d domain split up into convex subdomains. When it comes to hexahedrally meshing it there is still no method which provides overall simplicity, uniqueness, and robustness, and furthermore good mesh quality near those fracture planes as they govern the phenomena. For these cases we propose 2.75 d meshes. The basic idea is that the regions with steady state conditions need not be considered and, consequently they need not be meshed at all. Those regions are located far from the fractures. Accordingly, the 2.75 d mesh is a skeleton of 3 d elements covering the fracture planes in the domain. These can thus be analytically computed as layered hexahedral elements. Pre-requisites are a topological analysis of the domain and expertise in fluid dynamics in order to properly decide about the space to be omitted.

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