High-Performance Computing to Evaluate Hierarchical Heterogeneity Paradigms in Sedimentary Aquifer Systems
EMSL Project ID
30474
Abstract
We propose computational research that leads to a better understanding of processes governing ground-water flow and reactive mass transport in the subsurface. The goal is to produce simulations representing subsurface processes over an unprecedented range of scales, this requiring an unprecedented number of numerical grid nodes (62.5E+12). We will use a code that generates three-dimensional models representing five levels of organization within the hierarchical sedimentary architecture found in braid-belt deposits. The full model represents a domain 2.5 km by 2.5 km by 10 m thick with 1 cubic centimeter sized voxels. This code is almost perfectly scaleable.The code has been developed under a grant from the National Science Foundation (EAR 0510819), in collaboration with Drs. Timothy Scheibe and Vicky Freedman in the Hydrology Group at Pacific Northwest National Laboratory. The code has been tested by generating parts of the domain on desktop workstations, and with initial runs by Dr. Freedman on MPP2 at EMSL. In this proposal we seek an allocation of time in order to generate the full domain, to generate numerical tracer tests (with the code STOMP), and for work to address some of our questions on flow and transport in hierarchical sedimentary architecture, using the full model. The current NSF grant supports two PhD students for work and travel on this project through the end of this calendar year, and a pending NSF proposal would provide future support.
If successful in simulating all scales over the full domain, the full model will be distributed to the research community as a resource for testing ideas related to the upscaling problem, the inverse problem, and for other computational research requiring high-resolution base-case solutions.
Intellectual merit of the proposed activity: It is known that interconnected pathways of highly permeable sediments percolate at proportions lower than the threshold for an infinite random domain. We hypothesize that the percolation must be understood from not just the proportion of open-framework gravel cross-strata, but also from the proportions, geometry, and spatial distribution of larger-scale strata in which they occur. We propose a methodology for testing this hypothesis using the braid-belt model. Furthermore, we hypothesize that solutions to the upscaling problem will need to account for the presence of percolation, and for the hierarchy of unit types defined at different scales. We propose work to study the influence of percolation in hierarchical stratal architecture in a methodology for upscaling mechanical dispersion.
Broader impacts of the proposed activity: The research will have a general, positive impact on the research communitys ability to test emerging ideas in computational research on ground water flow and transport. The hypotheses we will test, using these models, are relevant to questions about environmental protection and cleanup, in general and at specific federal sites (Yucca Mt., Hanford, and Fernald). The project will benefit human resources and education in science and engineering through the training of two PhD students, who will gain expertise in high-performance computing, hydrogeology, and sedimentology, and will receive mentoring from university and national laboratory scientists.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2008-08-18
End Date
2011-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Guin, A., R. Ramanathan, D.F. Dominic, I.A. Lunt, V.L. Freedman, and T.D. Scheibe, 2010, Simulating the heterogeneity in channel belt deposits: Part 2. Examples of results and comparison to natural deposits, Water Resources Research, V. 46, doi:10.1029/2009WR008112
Ramanathan, R., A. Guin, R.W. Ritzi, D.F. Dominic, V.L. Freedman, T.D. Scheibe, and I.A. Lunt, 2010, Simulating the heterogeneity in channel belt deposits: A geometric-based methodology and code, Water Resources Research, V. 46, doi:10.1029/2009WR008111