Science Application: Turbulence

Project Title: Simulations of Turbulent Flows with Strong Shocks and Density Variations.

Principal Investigator: Sanjiva K. Lele
Affiliation: Stanford University

Participating Institutions and Co-Investigators:
Stanford University, Sanjiva K. Lele (PI), Parviz Moin
University of California at Los Angeles, Xiaolin Zhong
Lawrence Livermore National Laboratory, Andrew Cook, William Cabot, Bjorn Sjögreen
NASA Ames Research Center, Helen C. Yee

Funding Partners: Office of Science — Office of Advanced Scientific Computing Research and the National Nuclear Security Administration

Budget and Duration: Approximately $0.8 million per year for five years (Subject to acceptable progress review and the availability of appropriated funds)

Research Summary: Turbulent flows which also involve interactions with strong shocks and density variations arise in many diverse areas of science and technology. For example the explosive phenomena associated with supernova explosions, volcanic eruptions, accidental detonations involving natural gas leaks, shock wave lithotripsy to break up kidney stones, as well as the implosion of a cryogenic fuel capsule for inertial confinement fusion all involve dramatic compression and expansion of multi-phase materials, their turbulent mixing and chemical reactions. Strong shock waves, strong acceleration and deceleration of heterogeneous materials and associated turbulent mixing play a critical part in these phenomena. Besides the multi-scale hydrodynamic processes, these phenomena also involve other physics and chemistry rich in its complexity and nonlinearity, such as plasma physics, radiation transport, and complex chemical kinetics. The current ability to predict these flow phenomena is strongly limited by the models of turbulence used, and by the computational algorithms employed. This project, utilizing the petascale computational capabilities envisioned by the Department, provides an opportunity to revolutionize the scientific understanding of shock-turbulence interactions and multimaterial mixing in complex flows by simulations at unparalleled fidelity.

The project will consider turbulent flow configurations involving shock-turbulence interaction and multi-material mixing for fundamental scientific study, and for systematic model development, for example for use in large-eddy simulations in the context of applications to accelerated multi-material flows. The team will also systematically evaluate different novel numerical approaches for nonlinear, multi-scale shock-turbulence interaction flow problems to establish the best practices and rigorous benchmarks in large-eddy simulations.

Problems of shock-turbulence interaction present a philosophical dilemma in numerical algorithm development. Methods designed to treat discontinuities and shocks are inherently dissipative for turbulence, and methods designed for turbulence (fluctuating fields with broadband variations) are ineffective for discontinuities. Capturing the interactions at unprecedented realism requires novel algorithms and effective use of software tools which allow the full benefit of the new algorithms to be realized on the massively parallel computer architectures. These needed advances are possible only with closely knit interaction between the science applications and experts in numerical analysis, applied mathematics and computer science.

Relevance to DOE Mission: Flows involving the interaction of strong shocks with turbulence and density interfaces are central to laser-driven implosion of inertial confinement fusion plasmas, as well as in the broader Stockpile Stewardship mission of DOE. However, the current scientific understanding of shock-turbulence interactions in complex configurations, and the ability to reliably predict these strongly nonlinear multi-scale flows remains limited and imperfect. It is this area of science application, with relevance to inertial confinement fusion application and supernovae astrophysics, that the current Project aims to revolutionize by bringing together a team with deep expertise in numerical simulations of turbulence and turbulence physics, computational gas dynamics and shock wave physics, numerical analysis and nonlinear dynamics, and massively parallel computing.

Science Application: Materials Science and Chemistry

Project Title: Quantum Simulations of Materials and Nanostructures (Q-SIMAN)

Principal Investigator: Giulia Galli
Affiliation: University of California at Davis

Participating Institutions and Co-Investigators:
Lawrence Livermore National Laboratory, Eric Schwegler, Jean-Luc Fattebert, Tadashi Ogitsu, Andrew Williamson
Massachusetts Institute of Technology, Nicola Marzari
Stanford University, Wei Cai
University of California at Davis, Giulia Galli (PI), François Gygi, Warren E. Pickett, Zhaojun Bai
University of California at Santa Barbara, Nicola A. Spaldin
University of Illinois at Urbana Champaign, David M. Ceperley

Funding Partners: Office of Science — Office of Advanced Scientific Computing Research and the National Nuclear Security Administration

Budget and Duration: Approximately $1.2 million per year for five years (Subject to acceptable progress review and the availability of appropriated funds)

Research Summary: This project addresses a grand challenge in materials science and chemistry: predict and design molecular and materials properties with controllable accuracy from first principles (i.e., from the fundamental laws of quantum mechanics). In order to transform the quantum simulations techniques developed in the last several decades into predictive design and discovery tools, key progress in improving accuracy, robustness, efficiency and software performance and scalability is required. Specifically, the project will address:

• accuracy by focusing on ab initio molecular dynamics (AIMD) and quantum Monte Carlo (QMC) methods and on developing coupled AIMD/QMC approaches capable of describing materials in the presence of external perturbations;
• robustness by developing algorithms and codes for data analysis and validation;
• efficiency by improving linear scaling algorithms and codes; and
• software performance and scalability by developing specialized linear algebra algorithms and codes for both next-generation high performance platforms and commodity clusters.

This project will help to develop an ab initio foundry of codes, data and expertise, available to theorists, computational scientists and experimentalists alike. The methods and codes developed within this project will have broad applicability, and large-scale quantum simulations will be carried out for specific systems. These includes composite inorganic/organic nanomaterials for sensing applications, nanostructures in the presence of external fields for the simulation of realistic devices, fluids and solids under extreme conditions, the properties of water in materials science and biological environments, and materials relevant to energy storage and transformation.

Relevance to DOE Mission: The Department of Energy's mission is to advance the national, economic and energy security of the United States. Advances in materials and chemistry are often critical to progress in all three mission areas. For example, the development of advanced materials improves the efficiency, economy, environmental acceptability, and safety in energy generation, conversion, transmission, and utilization. This project is addressing a grand challenge in materials science and chemistry: predict and design molecular and materials properties with controllable accuracy from first principles.