1. SciDAC Projects: Groundwater Tim Scheibe PNNL-SA-52370

2. Science Application Hybrid Numerical Methods for Multiscale Simulations of Subsurface Biogeochemical Processes –Tim Scheibe (PNNL) – Principal Investigator Alexandre Tartakovsky, Bruce Palmer, Karen Schuhardt (PNNL) Paul Meakin, George Redden (INL) Daniel Tartakovsky (UC San Diego) Scott Brooks (ORNL)

3. Motivation “Scientifically rigorous models of subsurface reactive transport that accurately simulate contaminant mobility across multiple length scales remain elusive.” Reason: Disparity in scale between PROCESS and PHENOMENON

4. Two critical classes of problems: Problems with strong media heterogeneity at multiple scales Problems with strong coupling between flow, transport, and reaction processes

5. Na 2 CO 3 CaCl 2

6. Steady state solubility product. Non- reactive flow, Pe=2.8 t = 1000 t = 3000t = 1000 Changes in solubility product as result of precipitation. Reactive flow, Pe=2.8 t = 6000

7. Proposed Approach Hybrid Multiscale Modeling –Directly couple models with different process representations at fundamental scales –Adaptively control which processes / models are applied in which parts of the model domain

8. Examples of Multiscale Models Zoom Multiscale Systems Engineering Research Center (MSERC), Rensselaer Polytechnic Institute, Dr. Jacob Fish, PI

9. SciDAC Technologies and Collaborations Science Application Partnerships (SAPs): –Component Software Infrastructure for Achieving High Level Scalability in Groundwater Reactive Transport Modeling and Simulation (Palmer) –Process Integration, Data Management, and Visualization for Subsurface Simulations (Schuchardt) Visualization tools (multiscale) – VACET High-performance solvers – TOPS Advanced gridding technologies - ITAPS