Amanzi: An Open-Source Multi-process Simulator for Environmental Applications

Abstract:

The Advanced Simulation Capabililty for Environmental Management (ASCEM) program is developing an approach and open-source tool suite for standardized risk and performance assessments at legacy nuclear waste sites. These assessments begin with simplified models, and add geometric and geologic complexity as understanding is gained. The Platform toolsets (Akuna) generates these conceptual models and Amanzi provides the computational engine to perform the simulations, returning the results for analysis and visualization.

In this presentation we highlight key elements of the design, algorithms and implementations used in Amanzi. In particular, the hierarchical and modular design is aligned with the coupled processes being sumulated, and naturally supports a wide range of model complexity. This design leverages a dynamic data manager and the synergy of two graphs (one from the high-level perspective of the models the other from the dependencies of the variables in the model) to enable this flexible model configuration at run time. Moreover, to model sites with complex hydrostratigraphy, as well as engineered systems, we are developing a dual unstructured/structured capability. Recently, these capabilities have been collected in a framework named Arcos, and efforts have begun to improve interoperability between the unstructured and structured AMR approaches in Amanzi. To leverage a range of biogeochemistry capability from the community (e.g., CrunchFlow, PFLOTRAN, etc.), a biogeochemistry interface library was developed called Alquimia.

To ensure that Amanzi is truly an open-source community code we require a completely open-source tool chain for our development. We will comment on elements of this tool chain, including the testing and documentation development tools such as docutils, and Sphinx. Finally, we will show simulation results from our phased demonstrations, including the geochemically complex Savannah River F-Area seepage basins.