INCOMPLETE MIXING AND REACTIONS

Mixing-driven reactions are ubiquitous in natural environments and incomplete mixing has long plagued our ability to accurately predict them. Additionally, flows in natural subsurface environments are extremely complex: heterogeneous flow structures exist at multiple spatial scales from the pore-scale all the way to geologic scales. This results in non-uniform flow fields that can strongly influence mixing and thus reactive processes. In this talk we discuss a novel particle tracking method that naturally captures incomplete mixing effects to model bimolecular mixing-driven reactions. We apply this method to three different scenarios: (a) a system with no background flow and pure diffusion, (b) a system with a background shear flow and (c) a setup aiming to replicate column experiments where incomplete mixing effects have been documented. We discuss strengths and weaknesses of this method and demonstrate in particular how it is ideally suited to capturing the role of incomplete mixing.