Oberseminar Numerical Mathematics / Scientific Computing
Bernd Flemisch
IWS, Universität Stuttgart
A new fully implicit numerical model for miscible multi-phase flow in porous media
Abstract:
The tightly coupled, strongly nonlinear nature of non-isothermal multi-phase flow in porous media poses a tough challenge for numerical simulation. This trait is even more pronounced, if miscibility is also considered. A primary reason why inclusion of miscibility tends to be problematic are the difficulties stemming from phase transitions: on the one hand, phase transitions need to be included since the presence or absence of fluid phases has a major impact on the flow behavior; on the other hand, convergence of the nonlinear solver may be severely affected if they are not handled robustly.
In this talk, a mathematically sound approach to include phase transitions in the nonlinear system of equations is presented: first, the transition conditions are formulated as a set of local inequality constraints, which are then directly integrated into the nonlinear solver using a nonlinear complementarity function. Under this scheme, a semi-smooth Newton–Raphson solver exhibits considerably more robust convergence behavior compared to some previous approaches, which is illustrated by several numerical examples.
| Date: | 23.01.12 | Time: | 17:00 Uhr | Location: | FU Berlin, Institut für Mathematik, Arnimallee 6, 14195 Berlin. | Room: | 031 Basement |