title: Operator-splitting procedures for reactive transport and comparison of mass balance errors.
abstract: Operator-splitting (OS) techniques are very attractive for numerical modelling of reactive transport, but they induce some errors. Considering reactive mass transport with reversible and irreversible reactions governed by a first-order rate law, we develop analytical solutions of the mass balance for the following operator-splitting schemes: standard sequential non-iterative (SNI), Strang-splitting SNI, standard sequential iterative (SI), extrapolating SI, and symmetric SI approaches. From these analytical solutions, the operator-splitting methods are compared with respect to mass balance errors and convergence rates independently of the techniques used for solving each operator. Dimensionless times, NOS, are defined. They control mass balance errors and convergence rates. The following order in terms of decreasing efficiency is proposed: symmetric SI, Strang-splitting SNI, standard SNI, extrapolating SI and standard SI schemes. The symmetric SI scheme does not induce any operator-splitting errors, the Strang-splitting SNI appears to be O(N2OS) accurate, and the other schemes are first-order accurate.
authors.affiliation: Institut de Mécanique des Fluides et des Solides de l'Université Louis Pasteur, UMR 7507 Université Louis Pasteur-CNRS, 2 rue Boussingault, 67000 Strasbourg, France.
authors.forename: Jérôme
authors.initials: J
authors.lastname: Carrayrou
authors.forename: Robert
authors.initials: R
authors.lastname: Mosé
authors.forename: Philippe
authors.initials: P
authors.lastname: Behra
mesh_terms: D007700:Kinetics; D008962:Models, Theoretical; D015203:Reproducibility of Results; D012987:Soil; D013223:Statistics as Topic; D014872:Water Movements; D014881:Water Supply
chemical_list: D012987:Soil