Soutenance de thèse de Daniel Jara Heredia (Géosciences Rennes)



thesard.jpg

Le mercredi 21 juin 2017 à 13:30, salle de conf OSUR (Bât.14B, Campus de Beaulieu, Université de Rennes 1), Daniel Jara Heredia soutient sa thèse intitulée "Improvement of the numerical capacities of simulation tools for reactive transport modeling in porous media"

Le mercredi 21 juin 2017 à 13:30, salle de conf OSUR (Bât.14B, Campus de Beaulieu, Université de Rennes 1), Daniel Jara Heredia soutient sa thèse intitulée "Improvement of the numerical capacities of simulation tools for reactive transport modeling in porous media"

Devant le jury composé de :

· Michel KERN: Chercheur, Inria Rocquencourt / rapporteur
· Benoit NOETINGER : Directeur Expert, IFPEN / rapporteur
· Jocelyne ERHEL : Directrice de recherche, Inria Rennes / examinateur
· Luc AQUILINA : Professeur, Université de Rennes 1 / examinateur
· Benoit COCHEPIN : Ingénieur, Andra / examinateur
· Jean-Raynald DE DREUZY : Directeur de recherche, Université de Rennes 1 / directeur de thèse



Abstract
Reactive transport modeling in porous media involves the simulation of several physicochemical processes such as transport of species and geochemical reactions. The resolution of the system of equations that describes the problem can be obtained by a fully coupled approach or by a decoupled approach. Decoupled approaches can simplify the system of equations by breaking down the problem into smaller parts that are easier to handle. Each of the smaller parts can be solved with suitable integration techniques. The decoupling techniques might be noniterative (operator splitting methods) or iterative (fixedpoint iteration), having each its advantages and disadvantages. Noniterative approaches have an error associated with the separation of the coupled effects, and iterative approaches might have problems to converge.

In this thesis, we develop an open source code written in MATLAB (https://github.com/TReacLab/TReacLab) in order to model reactive transport problems. The code uses a decoupled approach. Classical operator splitting approaches, such as sequential, alternating or Strang splitting, and less classical splitting approaches, such as additive or symmetrically weighted splitting, have been implemented. Besides, two iterative approaches based on an specific formulation (SIA CC, and SIA TC) have also been implemented. The code has been interfaced in a generic way with different transport solvers (COMSOL, pdepe MATLAB, FVTool, FD scripts) and geochemical solvers (iPhreeqc, PhreeqcRM). In order to validate the implementation of the different approaches, a series of classical benchmarks in the field of reactive transport have been solved successfully and compared with analytical and external numerical solutions. Since the associated error due to the combination of operator splitting and numerical techniques may be complex to assess, we explore the existing mathematical tools used to evaluate it. Finally, we frame the atmospheric carbonation problem in a nuclear waste context and run preliminary simulations, stating the relevant problems and future steps to follow.




Contact OSUR :
Daniel Jara Heredia - @





0 Commentaires