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http://hdl.handle.net/1956/2230
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| Title: | Operator splitting methods for systems of convection-diffusion equations : nonlinear error mechanisms and correction strategies |
| Authors: | Karlsen, Kenneth Hvistendahl
Lie, K. A.
Natvig, J. R.
Nordhaug, Hans Fredrik
Dahle, Helge K. |
| Issue Date: | 2001 |
| Publisher: | Elsevier |
| Series/Report no.: | Journal of Computational Physics, 173(2):636-663 |
| Abstract: | Many numerical methods for systems of convection-diffusion equations are based upon an
operator splitting formulation, where convective and diffusive forces are accounted for in separate substeps.
We describe the nonlinear mechanism of the splitting error in such numerical methods in the onedimensional
case, a mechanism that is intimately linked to the local linearizations introduced implicitly
in the (hyperbolic) convection steps by the use of an entropy condition. For convection-dominated
flows, we demonstrate that operator splitting methods typically generate a numerical widening of viscous
fronts, unless the splitting step is of the same magnitude as the diffusion scale. To compensate
for the potentially damaging splitting error, we propose a corrected operator splitting (COS) method
for general systems of convection-diffusion equations with the ability of correctly resolving the nonlinear
balance between the convective and diffusive forces. In particular, COS produces viscous shocks
with correct structure also when the splitting step is large. A front tracking method for systems of
conservation laws, which in turn relies heavily on a Riemann solver, constitutes an important part of
our COS strategy. The proposed COS method is successfully applied to a system modelling two-phase,
multicomponent flow in porous media and a triangular system modelling three-phase flow. |
| Description: | Authors final draft post-refereeing. |
| URI: | http://hdl.handle.net/1956/2230 |
| ISSN: | 1090-2716 (online)
0021-9991 (print version) |
| Appears in Collections: | Department of Mathematics (Various)
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