1. Terascale Simulation Tools and Technology Center TSTT brings together existing mesh expertise from Labs and universities. State of the art: many high-quality tools that don’t interoperate Structured and hybrid meshesStructured and hybrid meshes Overture/Rapsodi (LLNL),Overture/Rapsodi (LLNL), Variational and elliptic grid generation (ORNL, SNL)Variational and elliptic grid generation (ORNL, SNL) Unstructured meshesUnstructured meshes MEGA (RPI), CUBIT (SNL), NWGrid (PNNL)MEGA (RPI), CUBIT (SNL), NWGrid (PNNL) Front-trackingFront-tracking FronTier (SUNY-SB/BNL)FronTier (SUNY-SB/BNL) Bringing this sophisticated technology to applications scientists is the challenge Interoperability and Interchangeability are the objectivesInteroperability and Interchangeability are the objectives Currently requires too much software expertise from application scientists to use the technologyCurrently requires too much software expertise from application scientists to use the technology We meet this challenge through a 2-pronged approachWe meet this challenge through a 2-pronged approach Near term: Deployment of current TSTT mesh and discretization capabilities by partnering with applicationsNear term: Deployment of current TSTT mesh and discretization capabilities by partnering with applications Long term: Development of interoperable software tools enabling rapid prototyping and plug-and-play insertion of technologyLong term: Development of interoperable software tools enabling rapid prototyping and plug-and-play insertion of technology Overture hybrid mesh generation for accelerator cavity geometry MEGA unstructured boundary layer mesh CUBIT was used to build a 400,000 element all-hex mesh on an accelerator PeP-II Interaction Region. This enabled the first successful direct calculation of the mode spectrum of this geometry. Atmospheric flows over mountain ranges respond dynamically to the variations in height these ranges present. We are developing enhanced mesh generation capabilities for anisotropic planar and geodesic surface meshes that are adapted and optimized to capture land surface orographic or topographic height fields. Atmospheric flows over mountain ranges respond dynamically to the variations in height these ranges present. We are developing enhanced mesh generation capabilities for anisotropic planar and geodesic surface meshes that are adapted and optimized to capture land surface orographic or topographic height fields. Technology successfully demonstrated in prototype simulations and now working to directly interface the mesh generation and adaptation tools directly with climate codes. Technology successfully demonstrated in prototype simulations and now working to directly interface the mesh generation and adaptation tools directly with climate codes. Adaptive mesh generation for climate modeling Orography field exhibiting high altitude regions of Himalayas and Alps Unstructured adapted geodesic mesh based on orographic field data Hybrid adapted geodesic mesh based on orographic field data Structured adapted spherical mesh based on orographic field data Spectral element discretizations for fusion We use high-order adaptive finite elements to solve the tilt instability problem. Two oppositely directed currents embedded in a constant B field. When perturbed, vortices turn and get expelled. We solve the incompressible MHD equations solved in stream function formulation using adaptive finite elements and a posteriori temporal and spatial error estimates of the magnetic field. Contacts: Jim Glimm, BNL Lori Freitag, LLNL David Brown, LLNL http://www.tstt-scidac.org UCRL-MI-145962 This work was performed under the auspices of the U.S. Department of Energy by University of California Lawrence Livermore National Laboratory under Contract W-7405-Eng-48. TSTT mesh generation, mesh optimization and discrete operators have been used in the development of the Virtual Microbial Cell Simulator. Microbial cell flocs are modeled using image reconstruction techniques to build a 3D geometry from a stack of confocal image slices (left). An unstructured mesh of the geometry is generated (center) and a set of reaction diffusion equations solved to get the concentration of oxygen in the floc (right). Mesh generation techniques aid computational biology applications Spectral Element discretization results are used to evaluate the diffusion in the toroidal cross- section with respect to the axial diffusion in possible fusion reactor configurations. These systems are difficult to model accurately because the ratio of diffusion coefficients can be as high as 10 9. Results for three different spectral element mesh cross sections show that for a fixed resolution, high order approximations are superior to low order in every case. Diffusion of an initially isolated Gaussian pulse following the magnetic field lines in the Tokamak using spectral element discretizations. Mesh Generation for Accelerator Applications Adaptive, high-order finite elements for fusion The current sheets and adaptive computational mesh for the tilt instability problem. TSTT error indicators, field function libraries, and adaptive refinement procedures are used to provide increasingly refined meshes to the SLAC Omega3P analysis code.TSTT error indicators, field function libraries, and adaptive refinement procedures are used to provide increasingly refined meshes to the SLAC Omega3P analysis code. The adaptive procedure has been applied to the Trispal cavity for which both experimental measurements and numerical results from standard codes are publicly available. The adaptive procedure has been applied to the Trispal cavity for which both experimental measurements and numerical results from standard codes are publicly available. Using only one-third the number of degrees of freedom, the new adaptive procedure reliably provides more accurate predictions than results using uniform refinement and gave the best agreement to experimental measurements. Using only one-third the number of degrees of freedom, the new adaptive procedure reliably provides more accurate predictions than results using uniform refinement and gave the best agreement to experimental measurements. Adaptive mesh simulations for accelerator applications

2. 3-D unstructured mesh simulations of the channeling phenomena in the growth of microbial biofilms on a flat plate. Merged NWGrid/ Frontier/Mesquite TSTT technology will be used to improve simulation results. Terascale Simulation Tools and Technology Center Interaction with SciDAC ISICs CCTTSS:SIDL/Babel language interoperability tools; performance studies of TSTT interface designCCTTSS:SIDL/Babel language interoperability tools; performance studies of TSTT interface design PERC: optimize performance of interoperable discretization operatorsPERC: optimize performance of interoperable discretization operators TOPS: joint development of a new optimization solver for the Mesquite mesh quality improvement toolkitTOPS: joint development of a new optimization solver for the Mesquite mesh quality improvement toolkit Technical Goal of the TSTT Center TSTT brings together many meshing and discretization tools that meet particular needs, but –They do not interoperate to form hybrid, composite meshes –They cannot be easily interchanged in an application Our goal is to provide interchangeable and interoperable access to different mesh management and discretization strategies Two Prong Development Strategy Create plug-and-play meshing and discretization components Create plug-and-play meshing and discretization components from existing technologies from existing technologies – Define common interfaces for mesh query and modification – Showcase interoperability goal through one-to-one demonstrations Develop new technologies as needed to enable interoperability Develop new technologies as needed to enable interoperability –Mesh quality improvement for hybrid meshes –High-level discretization library –Terascale algorithms for adaptivity, load balancing, interpolation Interface Definition Efforts PhilosophyPhilosophy - Create a small sets of interfaces that existing packages can support can support - Be data structure neutral - Balance performance and flexibility - Work with a large tool provider and application community Status Status - Mesh geometry and topology interfaces well underway Mesh Query Mesh Query Entity Sets (subsetting) Entity Sets (subsetting) Modifiable Meshes (a basic form of adaptive meshing) Modifiable Meshes (a basic form of adaptive meshing) - Prototype interfaces for geometry and field data - Prototype interface for mesh/geometry classification -Uses -Mesquite mesh quality improvement -Frontier Front tracking -Implementations AOMD, Overture, NWGrid, MDB/CUBIT AOMD, Overture, NWGrid, MDB/CUBIT C, C++, and Fortran language interoperability C, C++, and Fortran language interoperability through SIDL/Babel (CCA) through SIDL/Babel (CCA) One-to-One Interoperability Frontier (BNL/SUNY SB) - Overture (LLNL) MergeFrontier (BNL/SUNY SB) - Overture (LLNL) Merge –Combines adaptive mesh technology with Front-tracking –New AMR/Front tracking scheme used in instability simulations –Parallelizing adaptive schemes for a scalable solution strategy –Creating a TSTT-compliant Frontier-Lite library for use with other TSTT mesh management tools (NWGrid, AOMD) other TSTT mesh management tools (NWGrid, AOMD) NWGrid (PNNL) - Opt-MS (ANL)NWGrid (PNNL) - Opt-MS (ANL) –Incorporates previously developed mesh quality improvement tools –Uses a CCA interfaces for dynamic plug-and-play –Migration to Mesquite via the TSTT interface MESQUITE Mesh Quality Improvement Developing a stand-alone tool for mesh qualityDeveloping a stand-alone tool for mesh quality improvement improvement –hybrid, component based meshes –development of quality metrics for high order methods –a posteriori quality control using error estimators MethodsMethods –optimization-based smoothing and untangling (based on Opt-MS and CUBIT algorithms) (based on Opt-MS and CUBIT algorithms) StatusStatus –Version.8 released to TSTT partners –Tri, tet, quad, hex, and hybrid meshes –Several quality metrics and objective functions –Conjugate Gradient, Newton, Active Set solvers SciDAC ImpactSciDAC Impact –Stanford Linear Accelerator mesh quality improvement –General surface mesh improvement for Overture –Integrated with CUBIT, AOMD, Overture via TSTT interface Interoperability in SciDAC Applications The TSTT Data Hierarchy n n Level A: Geometric description n n Level B: Full geometry hybrid meshes n n Level C: Mesh Components The TSTT technology development plan Contacts: Jim Glimm, BNL Lori Freitag, LLNL David Brown, LLNL http://www.tstt-scidac.org UCRL-MI-145962 This work was performed under the auspices of the U.S. Department of Energy by University of California Lawrence Livermore National Laboratory under Contract W-7405-Eng-48. Mesquite successfully improves the quality of a general surface mesh from Overture. This capability will be used to generate higher quality meshes for the complex geometries in the SLAC accelerator applications. Richtmeyer-Meshkov instability simulation uses the Frontier/Overture merge to improve resolution and solution accuracy. Use TSTT philosophy and tools in adaptive accelerator applicationUse TSTT philosophy and tools in adaptive accelerator application TSTT error indicators, adaptation procedures and field data operations used to provide increasingly refined meshes to SLAC Omega3P codeTSTT error indicators, adaptation procedures and field data operations used to provide increasingly refined meshes to SLAC Omega3P code Mesh generation, mesh modification, and error estimation tools from different sources and interact through well-defined interfacesMesh generation, mesh modification, and error estimation tools from different sources and interact through well-defined interfaces