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Title: Terascale Simulation Tools and Technologies


We report the development of front tracking method as a simulation tool and technology for the computation on several important SciDAC and SciDAC associated applications. The progress includes the extraction of an independent software library from the front tracking code, conservative front tracking, applications of front tracking to the simulation of fusion pellet injection in a magnetically confined plasma, the study of a fuel injection jet, and the study of fluid chaotic mixing, among other problems.

Publication Date:
Research Org.:
Stony Brook University, Stony Brook, NY 11794
Sponsoring Org.:
USDOE - Energy Information Administration (EI)
OSTI Identifier:
Report Number(s):
DOE/FC/25461-5 Final Report
DOE Contract Number:
Resource Type:
Technical Report
Country of Publication:
United States
47 OTHER INSTRUMENTATION; Interoperable software, high resolution numerical algorithm, multiphase problem, front tracking

Citation Formats

Li, Xiaolin. Terascale Simulation Tools and Technologies. United States: N. p., 2007. Web. doi:10.2172/900578.
Li, Xiaolin. Terascale Simulation Tools and Technologies. United States. doi:10.2172/900578.
Li, Xiaolin. Fri . "Terascale Simulation Tools and Technologies". United States. doi:10.2172/900578.
title = {Terascale Simulation Tools and Technologies},
author = {Li, Xiaolin},
abstractNote = {We report the development of front tracking method as a simulation tool and technology for the computation on several important SciDAC and SciDAC associated applications. The progress includes the extraction of an independent software library from the front tracking code, conservative front tracking, applications of front tracking to the simulation of fusion pellet injection in a magnetically confined plasma, the study of a fuel injection jet, and the study of fluid chaotic mixing, among other problems.},
doi = {10.2172/900578},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Mar 09 00:00:00 EST 2007},
month = {Fri Mar 09 00:00:00 EST 2007}

Technical Report:

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  • The Terascale Simulation Tools and Technologies (TSTT) SciDAC center focused on the development and application on SciDAC applications of advanced technologies to support unstructured grid simulations. As part of the TSTT team the RPI group focused on developing automated adaptive mesh control tools and working with SciDAC accelerator and fusion applications on the use of these technologies to execute their simulations. The remainder of this report provides a brief summary of the efforts carried out by the RPI team to support SciDAC applications (Section 2) and to develop the TSTT technologies needed for those automated adaptive simulations (Section 3). Moremore » complete information on the technical developments can be found in the cited references and previous progress reports.« less
  • The overall goal of the TSTT Center is to enable the scientific community to more easily use modern high-order, adaptive, parallel mesh and discretization tools. To achieve this goal, we are following three distinct but related paths. The first is to work directly with a number of lead application teams (for the most part SciDAC-funded) to use such technologies in their application domains. The second is to create new technology that eases the use of such tools, not only for our designated application partners, but across a broad range of application areas that require mesh and discretization tools for scientificmore » simulation. The main technology thrust is not to create new tools (although some of this will occur), but to create new capabilities that will allow the use of these tools interoperably. This very profound step can be compared to the shift from hand craftmanship to manufactured products with interchangable components which revolutionized the world economy one to two centuries ago. The third component of our efforts is to embed this work in a larger framework of related activities, each seeking a similar, and profound, change in the practice of computational science. To ensure the relevance of our work to the SciDAC program goals, we originally selected six application areas, and in each, one or more application projects and teams with which to work directly. One application collaboration which targeted the development of an adaptive mesh refinement capability for the oceanographic code POP was postponed and may be dropped due to unanticipated technical obstacles in the specific goal selected. One new application involving jet breakup for spray combustion was added. The initial job of establishing good working relations, agreement on a plan of action, and obtaining initial results was accomplished in all cases. In general, our work with the applications has been more difficult than anticipated, in spite of the experience of the TSTT team members in similar application-motivated collaborations. For this reason, the routes to the goals have been modified in some cases, but good progress has been obtained for all of the targeted application teams. For example, in the case of the electromagnetic code for accelerator design, the original goal of developing more stable meshes has been enlarged to include the underlying difficulty which motivated this goal: to cure or ameliorate instabilities of the time stepping algorithm. With the fusion M3D code, we decided to work initially with a related, but smaller and more easily modified code from the same application team, for initial testing and proof of principle, as the full M3D code proved difficult to work with. In several applications (astrophysics, climate), our initial technology development goals were met, and while we await their use or evaluation, further collaborative goals will be pursued. The spray breakup problem achieved initial success and awaits adaptive TSTT technology to allow refined grid simulations for its next steps. We plan to continue the intensive effort to insert our existing advanced mesh and discretization technology into existing application codes for the coming year. Our main progress towards the development of new technology has been the definition of the low level interface to a variety of mesh generation and adaptive mesh management tools. This interface provides a common calling convention that will allow an application to call any compliant mesh tool in an interchangeable fashion. Most of the TSTT advanced meshing tools have been or will be made compliant to this interface. We have also pursued one-on-one interoperability goals with the development of interoperability between the FronTier front-tracking library and the Overture mesh library. This goal, advanced from year two to year one because of its need in one of our applications, has made good progress, and will be completed in the coming year. Finally, we mention the integration of this effort (interoperability and applications) with a larger computational science effort. The importance of this broader integration goal can be understood by recalling our larger goal of influencing the practice of computational science in a general sense. We have engaged the computational science community with an invitation to comment on our interoperability plan.« less
  • We develop scalable algorithms and object-oriented code frameworks for terascale scientific simulations on massively parallel processors (MPPs). Our research in multigrid-based linear solvers and adaptive mesh refinement enables Laboratory programs to use MPPs to explore important physical phenomena. For example, our research aids stockpile stewardship by making practical detailed 3D simulations of radiation transport. The need to solve large linear systems arises in many applications, including radiation transport, structural dynamics, combustion, and flow in porous media. These systems result from discretizations of partial differential equations on computational meshes. Our first research objective is to develop multigrid preconditioned iterative methods formore » such problems and to demonstrate their scalability on MPPs. Scalability describes how total computational work grows with problem size; it measures how effectively additional resources can help solve increasingly larger problems. Many factors contribute to scalability: computer architecture, parallel implementation, and choice of algorithm. Scalable algorithms have been shown to decrease simulation times by several orders of magnitude.« less
  • In this quarter (Q2 FY06), the DTEM underwent a substantial reconfiguration of its laser systems. The cathode laser system was changed to provide greater numbers of electrons per pulse by lengthening the time duration of the pulse to 30 ns. The greater number of electrons per pulse has allowed us to acquire high quality pulsed images and diffraction patterns. The spatial resolution in the single pulsed image has been measured at better than 20 nm. The diffraction patterns are now more comparable to conventional electron microscope operation. Examples are found in the body of the report. We summarize important achievementsmore » in the following list: (1) Instrument performance and design improvements--(A) The laser system was changed for the cathode photoemission system (75 ns at 1053 nm wavelength converted to 30ns at 211 nm wavelength) to give longer electron pulses at the same current to yield more electrons per pulse. (B) New specimen drive laser constructed. (C) New computer monitored and controlled alignment systems installed for both laser systems to facilitate laser alignment through a user friendly computer interface. (2) Experimental Progress--(A) The spatial resolution of pulsed images was tested by imaging a cross-section of multilayer thin foils with 30 nm and 20 nm periods. Single pulse images were observed to have spatial resolution better than 20 nm. This combination of 20 nm spatial and 30 ns temporal resolution is thought to be highest combined spatial and temporal measurement ever made. (B) The quality of single pulse electron diffraction patterns have been improved to the point where differentiating the HCP from BCC patterns in Ti is substantially easier. The spatial coherence of the electron illumination on the specimen was improved to give much smaller diffraction spots in the pattern.« less