H23B-0874:
Hybrid Multiscale Simulation of a Mixing-Controlled Reaction

Tuesday, 16 December 2014
Xiaofan Yang1, Timothy D Scheibe1, Karen Schuchardt1, Khushbu Agarwal1, Jared Chase1, Bruce Palmer1, Alexandre M Tartakovsky1,2 and Todd Elsethagen1, (1)Pacific Northwest National Laboratory, Richland, WA, United States, (2)University of South Florida, Department of Geosciences, Tampa, FL, United States
Abstract:
Continuum scale models have been used to study subsurface flow, transport, and reactions for many years but lack the capability to resolve fine-grained processes. Recently, pore-scale models, which operate at scales of individual soil grains, have been developed to more accurately model and study pore-scale phenomena, such as mineral precipitation and dissolution reactions, microbially-mediated surface reactions, and other complex processes. However, these highly-resolved models are prohibitively expensive for modeling domains of sizes relevant to practical problems. To broaden the utility of pore-scale models for larger domains, we developed a hybrid multiscale model that initially simulates the full domain at the continuum scale and applies a pore-scale model only to areas of high reactivity. Python script components provide loose coupling between the pore- and continuum-scale codes into a single hybrid multiscale model implemented in the SWIFT parallel scripting language. We consider an irreversible homogenous bimolecular reaction (two solutes reacting to form a third solute) in a 2D test problem. This presentation is focused on the approach used for multiscale coupling between pore- and continuum-scale models, application to a realistic test problem, and implications of the results for predictive simulation of mixing-controlled reactions in porous media. Our results and analysis demonstrate that loose coupling provides a feasible, efficient and scalable approach for multiscale subsurface simulations.