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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 505 records · Page 28
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

MIUS community conceptual design study

The feasibility, practicality, and applicability of the modular integrated utility systems (MIUS) concept to a satellite new-community development with a population of approximately 100,000 were analyzed. Two MIUS design options, the 29-MIUS-unit (option 1) and the 8-MIUS-unit (option 2) facilities were considered. Each resulted in considerable resource savings when compared to a conventional utility system. Economic analyses indicated that the total cash outlay and operations and maintenance costs for these two options were considerably less than for a conventional system. Computer analyses performed in support of this study provided corroborative data for the study group. An environmental impact assessment was performed to determine whether the MIUS meets or will meet necessary environmental standards. The MIUS can provide improved efficiency in the conservation of natural resources while not adversely affecting the physical environment.

Fulbright, B. E.↗
NASA NTRS1976

A new approach to the pulsed thermocouple for high gas temperature measurements

Pulsed thermocouple systems can be used to measure gas temperatures above the melting point of the thermocouple by various techniques of short term or intermittent exposure of the thermocouple operating at lower temperatures. This paper describes an approach which uses a thermocouple cooled by a small jet of inert gas. When a measurement is to be made, the cooling jet is turned off and the thermocouple allowed to heat up to near its melting point, at which time the cooling is reapplied. The final temperature which the thermocouple should have attained is then calculated by extrapolating an exponential curve fit to the data. Temperature measurements can be recorded and displayed in near real time by using modern high-speed computing systems to perform these calculations. Examples of the technique applied to high temperature jet engine combustor development are presented.

Glawe, G. E.↗
NASA NTRS1979

Performance evaluation of telecommunication systems using computer simulation

The SYSTID time domain digital simulation technique is reviewed. A technique is illustrated which estimates the signal to noise ratio at a point in the simulation of a communication system. Signals having a lowpass or bandpass spectra are utilized. Simulation results show the technique to be accurate over a wide range of signal to noise ratios. Examples which illustrate application to both analog and digital communication systems are provided.

Tranter, W. H.↗
NASA NTRS1978

Aircraft simulation data management - A prototype system

Piloted flight simulations are used throughout the aircraft development process to evaluate design concepts, handling qualities and operational procedures. Simulation project managers are often inundated with data but without a convenient and efficient way to make the correlations and analyses necessary to evaluate system performance. A computer-based Simulation Management System (SIMS) is under development. SIMS will permit simulation project engineers to quickly acquire, access, display, edit, analyze, and document the information necessary to more efficiently manage the research program. SIMS features interactive, associative access to simulation data. This paper describes SIMDEM, a prototype system designed to demonstrate these concepts and procedures in order to obtain feedback from simulator users to guide system design.

Crane, D. F.↗
NASA NTRS1981

Simulator certification methods and the vertical motion simulator

The vertical motion simulator (VMS) is designed to simulate a variety of experimental helicopter and STOL/VTOL aircraft as well as other kinds of aircraft with special pitch and Z axis characteristics. The VMS includes a large motion base with extensive vertical and lateral travel capabilities, a computer generated image visual system, and a high speed CDC 7600 computer system, which performs aero model calculations. Guidelines on how to measure and evaluate VMS performance were developed. A survey of simulation users was conducted to ascertain they evaluated and certified simulators for use. The results are presented.

Showalter, T. W.↗
NASA NTRS1991

The development of a CFD potential method for the analysis of tilt-rotors

A new CFD potential code, FPX (eXtended Full-Potential), has been developed for application to both helicopters and tilt-rotors. The code solves the unsteady, three-dimensional full potential equation and is an extension of the rotor code, FPR. Both entropy and viscosity corrections are included to enhance the physical modeling capabilities. A number of efficiency related modifications have yielded a factor of two speed-up in the code. An axial flow capability has been added to treat tilt-rotor in forward flight (cruise mode). In order to employ streamwise periodicity and accurately solve for the propagation of acoustic signals in the tip region, an H-H topology has been added to the basic O-H grid system. Computations are performed for the XV-15 Standard and ATB blades at high-speed conditions. Comparisons are made for the blade aerodynamics and the induced fuselage cabin pressure for a range of Mach numbers. Grid generation, wake treatment, and far-field wall treatment are identified as problem areas with recommendations for future research.

Bridgeman, John O.↗
NASA NTRS1993

Evaluation of the Intel iWarp parallel processor for space flight applications

The potential of a DARPA-sponsored advanced processor, the Intel iWarp, for use in future SSF Data Management Systems (DMS) upgrades is evaluated through integration into the Ames DMS testbed and applications testing. The iWarp is a distributed, parallel computing system well suited for high performance computing applications such as matrix operations and image processing. The system architecture is modular, supports systolic and message-based computation, and is capable of providing massive computational power in a low-cost, low-power package. As a consequence, the iWarp offers significant potential for advanced space-based computing. This research seeks to determine the iWarp's suitability as a processing device for space missions. In particular, the project focuses on evaluating the ease of integrating the iWarp into the SSF DMS baseline architecture and the iWarp's ability to support computationally stressing applications representative of SSF tasks.

Hine, Butler P., III↗
NASA NTRS1992

Artificial Intelligence Research Branch future plans

This report contains information on the activities of the Artificial Intelligence Research Branch (FIA) at NASA Ames Research Center (ARC) in 1992, as well as planned work in 1993. These activities span a range from basic scientific research through engineering development to fielded NASA applications, particularly those applications that are enabled by basic research carried out in FIA. Work is conducted in-house and through collaborative partners in academia and industry. All of our work has research themes with a dual commitment to technical excellence and applicability to NASA short, medium, and long-term problems. FIA acts as the Agency's lead organization for research aspects of artificial intelligence, working closely with a second research laboratory at the Jet Propulsion Laboratory (JPL) and AI applications groups throughout all NASA centers. This report is organized along three major research themes: (1) Planning and Scheduling: deciding on a sequence of actions to achieve a set of complex goals and determining when to execute those actions and how to allocate resources to carry them out; (2) Machine Learning: techniques for forming theories about natural and man-made phenomena; and for improving the problem-solving performance of computational systems over time; and (3) Research on the acquisition, representation, and utilization of knowledge in support of diagnosis design of engineered systems and analysis of actual systems.

Stewart, Helen↗
NASA NTRS1998

Report on the Acceptance Test of the CRI Y-MP 8128, 10 February - 12 March 1990

The NAS Numerical Aerodynamic Simulation Facility's HSP 2 computer system, a CRI Y-MP 832 SN #1002, underwent a major hardware upgrade in February of 1990. The 32 MWord, 6.3 ns mainframe component of the system was replaced with a 128 MWord, 6.0 ns CRI Y-MP 8128 mainframe, SN #1030. A 30 day Acceptance Test of the computer system was performed by the NAS RND HSP group from 08:00 February 10, 1990 to 08:00 March 12, 1990. Overall responsibility for the RND HSP Acceptance Test was assumed by Duane Carbon. The terms of the contract required that the SN #1030 achieve an effectiveness level of greater than or equal to ninety (90) percent for 30 consecutive days within a 60 day time frame. After the first thirty days, the effectiveness level of SN #1030 was 94.4 percent, hence the acceptance test was passed.

Carter, Russell↗
NASA NTRS1998

Challenges of Future High-End Computing

The next major milestone in high performance computing is a sustained rate of one Pflop/s (also written one petaflops, or 10(circumflex)15 floating-point operations per second). In addition to prodigiously high computational performance, such systems must of necessity feature very large main memories, as well as comparably high I/O bandwidth and huge mass storage facilities. The current consensus of scientists who have studied these issues is that "affordable" petaflops systems may be feasible by the year 2010, assuming that certain key technologies continue to progress at current rates. One important question is whether applications can be structured to perform efficiently on such systems, which are expected to incorporate many thousands of processors and deeply hierarchical memory systems. To answer these questions, advanced performance modeling techniques, including simulation of future architectures and applications, may be required. It may also be necessary to formulate "latency tolerant algorithms" and other completely new algorithmic approaches for certain applications. This talk will give an overview of these challenges.

Bailey, David↗
NASA NTRS2004

Using Science Driven Technologies for the Defense and Security Applications

For the past three decades, Earth science remote sensing technologies have been providing enormous amounts of useful data and information in broadening our understanding of our home planet as a system. This research, as it has expanded our learning process, has also generated additional questions. This has further resulted in establishing new science requirements, which have culminated in defining and pushing the state-of-the-art technology needs. NASA s Earth science program has deployed 18 highly complex satellites, with a total of 80 sensors, so far and is in a process of defining and launching multiple observing systems in the next decade. Due to the heightened security alert of the nation, researchers and technologists are paying serious attention to the use of these science driven technologies for dual use. In other words, how such sophisticated observing and measuring systems can be used in detecting multiple types of security concerns with a substantial lead time so that the appropriate law enforcement agencies can take adequate steps to defuse any potential risky scenarios. This paper examines numerous NASA technologies such as laser/lidar systems, microwave and millimeter wave technologies, optical observing systems, high performance computational techniques for rapid analyses, and imaging products that can have a tremendous pay off for security applications.

Habib, Shahid↗
NASA NTRS2022

VULCAN-CFD User Manual: Ver. 7.2.0

VULCAN-CFD offers a comprehensive set of capabilities to enable the simulation of continuum flowfields from subsonic to hypersonic conditions. The governing equations that are employed include allowances for both chemical and thermal nonequilibrium processes, coupled with a wide variety of turbulence models for both Reynolds-averaged and large eddy simulations. The software package can simulate two-dimensional, axisymmetric, or three-dimensional problems on structured multiblock meshes or fully unstructured meshes. A parabolic (i.e., space-marching) treatment can also be used for any subset of a structured mesh that can accommodate this solution strategy. The flow solver provides a significant level of geometric flexibility for structured grid simulations by allowing for arbitrary face-to-face C(0) continuous and non-C(0) continuous block interface connectivities. The unstructured grid paradigm allows for mixed element unstructured meshes that contain any combination of tetrahedral, prismatic, pyramidal, and hexahedral cell elements. The flow solver is also fully parallelized using MPI (Message Passing Interface) libraries in a data-parallel fashion, allowing for efficient simulations on modern High Performance Computing (HPC) systems. This document provides information related to the installation and execution of the VULCAN-CFD software package. A detailed description of the physical and numerical models available in the software are provided in the VULCAN-CFD Theory Manual.

VULCAN-CFD User Manual↗
DOE OSTI2020

Orchestrating Fault Prediction with Live Migration and Checkpointing

Checkpoint/Restart (C/R) is widely used to provide fault tolerance on High-Performance Computing (HPC) systems. However, Parallel File System (PFS) overhead and failure uncertainty cause significant application overhead. This paper develops an adaptive multi-level C/R model that incorporates a failure prediction and analysis model, which orchestrates failure prediction, checkpointing, checkpoint frequency, and proactive live migration along with the additional benefit of Burst Buffers (BB). It effectively reduces the overheads due to failures, checkpointing, and recovery. Simulation results for the Summit supercomputer yield a reduction of ~20%-86% in application overhead due to BBs, orchestrated failure prediction, and migration. We also observe a ~29% decrease in checkpoint writes to BBs, which can increase the longevity of the BB storage devices.

Behera, Subhendu↗
DOE OSTI2020

Towards Acceptance Testing at the Exascale Frontier

At the 2007 Cray User Group meeting, the Oak Ridge Leadership Computing Facility (OLCF) introduced the OLCF Test Harness (OTH), a framework[1] used for acceptance testing of the Jaguar supercomputer[2]. Since then, the OTH framework has evolved to version 2.0 which adds new features and streamlines usability. The OTH is the key piece of software used to orchestrate acceptance testing for all OLCF computational resources before they are deployed for production use, including our leadership class high performance computing (HPC) systems. The OTH framework is written in Python and is publicly available[3].In this paper, we first describe the requirements, design, and structure of the OTH. Then, we present specific improvements developed to support acceptance testing of the OLCF’s Summit system[4]. We will also showcase new OTH features that have been added to streamline the acceptance test process as well as the motivation behind those changes. As part of this work, we also evaluated different workflow tools in order to determine whether these tools could complement the OTH in two key areas: automation and reporting. The advantages and disadvantages identified with each tool will be discussed. Lastly, we summarize the challenges and lessons learned collected from using the OTH for the acceptance of the last three flagship systems at the OLCF. These may be useful for other HPC centers developing their own testing frameworks or those interested in using the OTH.

Melesse Vergara, Veronica↗
DOE OSTI2024

Software engineering to sustain a high-performance computing scientific application: QMCPACK

We provide an overview of the software engineering efforts and their impact in QMCPACK, a production-level ab-initio Quantum MonteCarlo open-source code targeting high-performance computing (HPC) systems. Aspects included are: (i) strategic expansion ofcontinuous integration (CI) targeting CPU, using GitHub Actions runners, and graphics processing units (GPU) in pre-exascalesystems, using self-hosted hardware; (ii) incremental reduction of memory leaks using sanitizers, (iii) incorporation of Dockercontainers for CI and reproducibility, and (iv) refactoring efforts to improve maintainability, testing coverage, and memory lifetime management. We quantify the value of these improvements by providing metrics to illustrate the shift towards a predictive, rather than reactive, sustainable maintenance approach. Our goal, in documenting the impact of these efforts on QMCPACK, is to contribute to the body of knowledge on the importance of research software engineering (RSE) for the sustainability of community HPC codes and scientific discovery at scale.

Godoy, William↗
DOE OSTI2024

Advanced Computing Annual Report 2023

In 2023, advanced computing saw the arrival of Kestrel, the National Renewable Energy Laboratory's (NREL's) newest high-performance computing (HPC) system. Kestrel will accelerate clean energy research at a pace and scale more than five times greater than Eagle, with approximately 44 petaflops of computing power. Kestrel's heterogeneous architecture - which includes both CPU-only and GPU-accelerated nodes - is designed to bring a much greater GPU capacity to EERE workloads compared to Eagle, enabling rapidly advancing applications in artificial intelligence and expanding research in new directions for computing. In Fiscal Year (FY) 2023, 333 projects utilized NREL's HPC system, advancing the U.S. Department of Energy's (DOE's) Office of Energy Efficiency and Renewable Energy (EERE) mission across 13 funding areas. Cross-disciplinary collaboration among researchers yielded more than 800 technical outputs, including 177 peer-reviewed journal articles in FY 2023. All this great work continues to advance the science of energy efficiency and renewable energy. This report highlights research that utilized HPC resources in FY 2023.

advanced computing↗
DOE OSTI2025

Advanced Computing Annual Report 2024

In fiscal year (FY) 2024, the National Renewable Energy Laboratory (NREL) took a major leap forward with the completed full buildout of Kestrel, the Office of Energy Efficiency and Renewable Energy's newest high-performance computing (HPC) system. Kestrel is already supporting science across the portfolio, bringing roughly 44 petaflops of computing power, which is more than five times the capacity of our previous supercomputer, Eagle. By delivering greater GPU capacity, Kestrel enables faster progress in artificial intelligence (AI) and opens new avenues in energy research - from defining long-term planning scenarios to accommodate a growing power system to material discovery to improving energy efficiency in photovoltaics (PV). Across the portfolio, research is being accelerated by Kestrel's impressive power. During FY24, 427 projects and more than 700 researchers used NREL's HPC, supporting the U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy across 13 funding areas. Through these collaborations, researchers produced more than 450 technical outputs, including 195 articles in peer-reviewed publications, pushing the boundaries of science and engineering. This year's report features new sections spotlighting the expanding roles of Artificial Intelligence and Accelerated Computing. We also introduce an early career section to celebrate the accomplishments of our up-and-coming researchers, whose pioneering work is shaping the future of energy. We hope you enjoy the new insights and discoveries highlighted in these pages.

97 MATHEMATICS AND COMPUTING↗