The MoMaS Reactive Transport BenchmarkPresentation of the Models1 2Jérôme Carrayrou Michel Kern1Université Louis Pasteur, IMFS, Strasbourg, France2INRIA Rocquencourt, FranceModelling Reactive Transport in Porous MediaStrasbourg, January 21-24, 2008Carrayrou & Kern (IMFS,& INRIA) Reactive transport benchmark 23rd Jan 2008 1 / 13Plan1 Introduction2 Mathematical model3 Geometry and chemical data4 ConclusionsCarrayrou & Kern (IMFS,& INRIA) Reactive transport benchmark 23rd Jan 2008 2 / 13ConsequencesSynthetic chemical systemSmall number of species / reactionsUnrealistic stoichiometry, equilibrium constantsSeveral levels of difficultyMotivationDesign decisionsCompare numerical methods and codes for reactive transportBias towards nuclear waste disposalFixed physical / chemical modelSimple chemical system, with high numerical complexityNo thermodynamic databaseCarrayrou & Kern (IMFS,& INRIA) Reactive transport benchmark 23rd Jan 2008 3 / 13MotivationDesign decisionsCompare numerical methods and codes for reactive transportBias towards nuclear waste disposalFixed physical / chemical modelSimple chemical system, with high numerical complexityNo thermodynamic databaseConsequencesSynthetic chemical systemSmall number of species / reactionsUnrealistic stoichiometry, equilibrium constantsSeveral levels of difficultyCarrayrou & Kern (IMFS,& INRIA) Reactive transport benchmark 23rd Jan 2008 3 / 13Time discretizationExplicit /implicitLower /higher ...
Compare numerical methods and codes for reactive transport Bias towards nuclear waste disposal Fixed physical / chemical model Simple chemical system, with high numerical complexity No thermodynamic database
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Design decisions Compare numerical methods and codes for reactive transport Bias towards nuclear waste disposal Fixed physical / chemical model Simple chemical system, with high numerical complexity No thermodynamic database
Motivation
Consequences Synthetic chemical system Small number of species / reactions Unrealistic stoichiometry, equilibrium constants Several levels of difficulty
Coupling methods Operator splitting To iterate or not to iterate, OS error control Global DSA, DAE, Newton (non-linear system solution, linear algebra, ...)
Space discretization Features Stability, numerical diffusion, efficiency Methods Finite element / volumes, Ellam, particles, ...
Time discretization Explicit /implicit Lower /higher order Adaptive time step (heuristic, residual based)
ω∂ T M j ∂ t + T F j + r . ω uT M j − r . D r T M j = − ω X k ac k , j f k ( C i , Cc k )
Dispersion tensor D = α T ω | u | I + ( α L − α T ) ω u |⊗ u | u T M j (resp. T F j ) total mobile (resp. immobile) for concentration component j , kinetic source term, rate f k ( C i , Cc k )
Saturated flow : Darcy’s law ( ω u = − K r h r . ( ω u ) = 0