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At least 289 records · Page 16

High-Performance Parallel Analysis of Coupled Problems for Aircraft Propulsion

Applications are described of high-performance computing methods to the numerical simulation of complete jet engines. The methodology focuses on the partitioned analysis of the interaction of the gas flow with a flexible structure and with the fluid mesh motion driven by structural displacements. The latter is treated by a ALE technique that models the fluid mesh motion as that of a fictitious mechanical network laid along the edges of near-field elements. New partitioned analysis procedures to treat this coupled three-component problem were developed. These procedures involved delayed corrections and subcycling, and have been successfully tested on several massively parallel computers, including the iPSC-860, Paragon XP/S and the IBM SP2. The NASA-sponsored ENG10 program was used for the global steady state analysis of the whole engine. This program uses a regular FV-multiblock-grid discretization in conjunction with circumferential averaging to include effects of blade forces, loss, combustor heat addition, blockage, bleeds and convective mixing. A load-balancing preprocessor for parallel versions of ENG10 was developed as well as the capability for the first full 3D aeroelastic simulation of a multirow engine stage. This capability was tested on the IBM SP2 parallel supercomputer at NASA Ames.

Felippa, C. A.↗

Mars Global Surveyor: Aerobraking and Observations Support Using a Mars Global Circulation Model

This is a Final Report for a Joint Research Interchange (JRI) between NASA Ames Research Center and San Jose State University, Department of Meteorology. Using a global atmospheric circulation model for Mars, the focus of this JRI has been to provide support for the Mars Global Surveyor (MGS) spacecraft aerobraking activities and interpretation guidance of preliminary observations. The primary atmospheric model applied in this investigation has been a high-top version of the NASA Ames Mars general circulation model (MGCM). Comparisons with an atmospheric model designed primarily for engineering purposes (Mars-GRAM) has also been carried out. From a suite of MGCM simulations, we have assessed plausible spatial and temporal variability in atmospheric density at high altitudes (e.g., 70-110 km) for seasonal dates and locations during Phase I aerobraking. Diagnostic tools have been developed to analyze circulation fields from the MGCM simulations, and these tools have been applied in the creation of a Mars climate catalogue database. Throughout Phase I aerobraking activities, analysis products have been provided to the MGS aerobraking atmospheric advisory group (AAG). Analyses of circulation variability at the coupling level between the MGCM and a Mars thermospheric global circulation model (MTGCM) has also been assessed. Finally, using a quasi-geostrophic dynamical formulation with the MGCM simulations, diagnosis of breaking planetary (Rossby) waves in Mars' middle atmosphere has been carried out. Titles of papers presented at scientific workshops and seminars, and a publication in the scientific literature are provided.

Hollingsworth, Jeffery L.↗

Mars Global Surveyor: Aerobraking and Observations Support Using a Mars Global Circulation Model

This is a Final Report for a Joint Research Interchange (JRI) between NASA Ames Research Center and San Jose State University, Department of Meteorology. Using a global atmospheric circulation model for Mars, the focus of this JRI has been to provide support for the Mars Global Surveyor (MGS) spacecraft aerobraking activities and interpretation guidance of preliminary observations. The primary atmospheric model applied in this investigation has been a high-top version of the NASA Ames Mars general circulation model (MGCM). Comparisons with an atmospheric model designed primarily for engineering purposes (Mars-GRAM) has also been carried out. From a suite of MGCM simulations, we have assessed plausible spatial and temporal variability in atmospheric density at high altitudes (e.g., 70-1 10 km) for seasonal dates and locations during Phase 1 aerobraking. Diagnostic tools have been developed to analyze circulation fields from the MGCM simulations, and these tools have been applied in the creation of a Mars climate catalogue database. Throughout Phase I aerobraking activities, analysis products have been provided to the MGS aerobraking atmospheric advisory group (AAG). Analyses of circulation variability at the coupling level between the MGCM and a Mars thermospheric global circulation model (MTGCM) has also been assessed. Finally, using a quasi-geostrophic dynamical formulation with the MGCM simulations, diagnosis of breaking planetary (Rossby) waves in Mars middle atmosphere has been carried out. Titles of papers presented at scientific workshops and seminars, and a publication in the scientific literature are provided.

Hollingsworth, Jeffery L.↗

Mars Global Surveyor: Aerobraking and Observations Support Using a Mars Global Circulation Model

This is a Final Report for a Joint Research Interchange (JRI) between NASA Ames Research Center and San Jose State University, Department of Meteorology. Using a global atmospheric circulation model for Mars, the focus of this JRI has been to provide support for the Mars Global Surveyor (MGS) spacecraft aerobraking activities and interpretation guidance of preliminary observations. ne primary atmospheric model applied in this investigation has been a high-top version of the NASA Ames Mars general circulation model (MGCM). Comparisons with an atmospheric model designed primarily for engineering purposes (Mars-GRAM) has also been carried out. From a suite of MGCM simulations, we have assessed plausible spatial and temporal variability in atmospheric density at high altitudes (e.g., 70-110 km) for seasonal dates and locations during Phase 1 aerobraking. Diagnostic tools have been developed to analyze circulation fields from the MGCM simulations, and these tools have been applied in the creation of a Mars climate catalogue database. Throughout Phase 1 aerobraking activities, analysis products have been provided to the MGS aerobraking atmospheric advisory group (AAG). Analyses of circulation variability at the coupling level between the MGCM and a Mars thermospheric global circulation model (MTGCM) has also been assessed. Finally, using a quasi-geostrophic dynamical formulation with the MGCM simulations, diagnosis of breaking planetary (Rossby) waves in Mars' middle atmosphere has been carried out. Titles of papers presented at scientific workshops and seminars, and a publication in the scientific literature are provided.

Hollingsworth, Jeffery L.↗

Development of a General Method for Determining Leak Rates from Limiting Enclosures

This paper discusses the development of a general method for the determination of very low leak rates from limiting enclosures. There are many methods that can be used to detect and repair leaks from enclosures. Many methods have also been proposed that allow the estimation of actual leak rates, usually expressed as enclosure volume turnover. The proposed method combines measurements of the state variables (pressure, temperature, and volume) as well as the change in the concentration of a tracer gas to estimate the leak rate. The method was applied to the containment enclosure of the Engineering Development Unit of the CELSS Test Facility, currently undergoing testing at the NASA Ames Research Center.

Zografos, A. I.↗

Toolsets Maintain Health of Complex Systems

First featured in Spinoff 2001, Qualtech Systems Inc. (QSI), of Wethersfield, Connecticut, adapted its Testability, Engineering, and Maintenance System (TEAMS) toolset under Small Business Innovation Research (SBIR) contracts from Ames Research Center to strengthen NASA's systems health management approach for its large, complex, and interconnected systems. Today, six NASA field centers utilize the TEAMS toolset, including TEAMS-Designer, TEAMS-RT, TEAMATE, and TEAMS-RDS. TEAMS is also being used on industrial systems that generate power, carry data, refine chemicals, perform medical functions, and produce semiconductor wafers. QSI finds TEAMS can lower costs by decreasing problems requiring service by 30 to 50 percent.

Source record↗

A Look at the Impact of High-End Computing Technologies on NASA Missions

From its bold start nearly 30 years ago and continuing today, the NASA Advanced Supercomputing (NAS) facility at Ames Research Center has enabled remarkable breakthroughs in the space agency s science and engineering missions. Throughout this time, NAS experts have influenced the state-of-the-art in high-performance computing (HPC) and related technologies such as scientific visualization, system benchmarking, batch scheduling, and grid environments. We highlight the pioneering achievements and innovations originating from and made possible by NAS resources and know-how, from early supercomputing environment design and software development, to long-term simulation and analyses critical to design safe Space Shuttle operations and associated spinoff technologies, to the highly successful Kepler Mission s discovery of new planets now capturing the world s imagination.

Biswas, Rupak↗

Fe3 Traffic Simulator Overview

NASA Ames developed a first of its kind air traffic simulation tool known as Flexible engine for Fast time evaluation of Flight environments (Fe3). The patent-pending technology is a robust simulation tool that provides the capability of statistically analyzing the high-density and low-altitude traffic system. With this capability, stakeholders can study the impacts of critical components (such as wind, surveillance, communication, collision, avoidance, traffic rules, energy consumption, etc.) in the low-altitude high-density traffic system, gain insights and help define requirements, policies, and protocols for a safe and efficient traffic system, and assess operational risks and optimize fight schedules.

Flexible engine for Fast time evaluation of Flight↗

The NASA Space Life Sciences Training Program (SLSTP)

The NASA Space Life Sciences Training Program (SLSTP) provides undergraduate students entering their junior or senior years with professional experience in space life science disciplines. This challenging ten-week summer program is hosted by NASA Ames Research Center. The primary goal of the program is to train the next generation of scientists and engineers, enabling NASA to meet future research and development challenges in the space life sciences. SLSTP Research Associates (RAs) work closely with NASA scientists and engineers on cutting-edge research and technology development. In addition to providing hands-on research experience and the ability to present their findings in a professional forum, SLSTP RAs attend technical lectures given by experts on a wide range of topics, tour NASA and other research facilities, participate in leadership and team building exercises, and develop a group project. Historically the SLSTP program has been held at Ames Research Center in Mountain View, California. However, due to the pandemic, both the 2020 and 2021 programs were restructured to be conducted virtually, enabling the program to continue despite the challenging times. For this presentation, we will highlight program processes, student recruitment, accomplishments, goals, and feedback from alumni and mentors since 2013. To date, 92 RAs from 64 different academic institutions in 29 states, 21 staffers, and 37 mentors have participated in the program. The SLSTP is funded by NASA’s Space Biology Program, which is part of the Biological and Physical Sciences Division of NASA. The SLSTP is managed by the Space Biology Project within the Science Directorate at Ames Research Center.

Training Space Biosciences Student↗

Effect of propeller slipstream on the drag and performance of the engine cooling system for a general aviation twin-engine aircraft

The pressure recovery of incoming cooling air and the drag associated with engine cooling of a typical general aviation twin-engine aircraft was investigated experimentally. The semispan model was mounted vertically in the 40- by 80-Foot Wind Tunnel at Ames Research Center. The propeller was driven by an electric motor to provide thrust with low vibration levels for the cold-flow configuration. It was found that the propeller slipstream reduces the frontal air spillage around the blunt nacelle shape. Consequently, this slipstream effect promotes flow reattachment at the rear section of the engine nacelle and improves inlet pressure recovery. These effects are most pronounced at high angles of attack, that is, climb condition. For the cruise condition those improvements were more moderate.

Katz, J.↗

Effect of Propeller on Engine Cooling System Drag and Performance

The pressure recovery of incoming cooling air and the drag associated with engine cooling of a typical general aviation twin-engine aircraft was Investigated experimentally. The semispan model was mounted vertically in the 40 x 80-Foot Wind Tunnel at Ames Research Center. The propeller was driven by an electric motor to provide thrust with low vibration levels for the cold-now configuration. It was found that the propeller slip-stream reduces the frontal air spillage around the blunt nacelle shape. Consequently, this slip-stream effect promotes flow reattachment at the rear section of the engine nacelle and improves inlet pressure recovery. These effects are most pronounced at high angles of attack; that is, climb condition. For the cruise condition those improvements were more moderate.

Katz, Joseph↗

Takeoff predictions for powered-lift aircraft

Takeoff predictions for powered lift short takeoff (STO) aircraft have been added to NASA Ames Research Center's aircraft synthesis (ACSYNT) code. The new computer code predicts the aircraft engine and nozzle settings required to achieve the minimum takeoff roll. As a test case, it predicted takeoff around rolls and nozzle settings for the YAV-8B Harrier that were close to the actual values. Analysis of takeoff performance for an ejector-augmentor design and a vectoring-nozzle design indicated that ground roll can be decreased, for either configuration, by horizontally moving the rear thrust vector closer to the center of gravity, by increasing the vertical position of the ram drag-vector, or by moving the rear thrust vector farther below the center of gravity.

Wardwell, Douglas A.↗

Takeoff predictions for powered-lift aircraft

Takeoff predictions for powered-lift short takeoff (STO) and conventional takeoff (CTO) aircraft have been added to NASA Ames Research Center's Aircraft Synthesis (ACSYNT) code. The new computer code predicts the aircraft engine and nozzle settings required to achieve the minimum takeoff roll. As a test case, the code predicted takeoff ground rolls and nozzle settings for the YAV-8B Harrier that compared well with measured values. Brief analysis of takeoff performance for an Ejector, Remote Augmented Lift, Hybrid-Tandem Fan, and Vectored Thrust STO aircraft using the new routine will be presented.

Wardwell, Douglas A.↗

Lessons learned in the development of the STOL intelligent tutoring system

Lessons learned during the development of the NASA Systems Test and Operations Language (STOL) Intelligent Tutoring System (ITS), being developed at NASA Goddard Space Flight Center are presented. The purpose of the intelligent tutor is to train STOL users by adapting tutoring based on inferred student strengths and weaknesses. This system has been under development for over one year and numerous lessons learned have emerged. These observations are presented in three sections, as follows. The first section addresses the methodology employed in the development of the STOL ITS and briefly presents the ITS architecture. The second presents lessons learned, in the areas of: intelligent tutor development; documentation and reporting; cost and schedule control; and tools and shells effectiveness. The third section presents recommendations which may be considered by other ITS developers, addressing: access, use and selection of subject matter experts; steps involved in ITS development; use of ITS interface design prototypes as part of knowledge engineering; and tools and shells effectiveness.

Seamster, Thomas↗

Are highly parallel systems ready for prime time?

This is the edited and abbreviated transcript of a panel discussion held on May 9, 1989, in Los Angeles, during the conference "Parallel Computational Fluid Dynamics-Implementations and Results Using MIMD Computers." The purpose of the conference was to discuss recent developments in the use of MIMD parallel computers in high-performance computational fluid dynamics. The intent of the panel discussion was to summarize the findings of the meeting, and to give a perspective on the state of the art in using parallel computers for solving large-scale engineering and scientific application problems. The panelists were Creon Levit (NAS Systems Division, NASA-Ames Research Center, Moffett Field, California), Kent Misegades (Cray Research, Inc., Mendota Heights, Minnesota), Gary Montry (Myrias Computer Corporation, Albuquerque, New Mexico), Ken Neves (Boeing Computer Services, Seattle, Washington), Anthony Patera (Massachusetts Institute of Technology, Cambridge, Massachusetts), and Justin Rattner (Intel Scientific Computers, Beaverton, Oregon).

Simon, Horst D.↗

Initial Closed Operation of the CELSS Test Facility Engineering Development Unit

As part of the NASA Controlled Ecological Life Support System (CELSS) Program, a CELSS Test Facility (CTF) is being planned for installation on the Space Station. The CTF will be used to provide data on the productivity and efficiency of a variety of CELSS higher plant crops grown sequentially from seed to harvest in the microgravity environment of the Space Station. Stringent environmental control will be maintained while fundamental crop productivity issues, such as carbon dioxide uptake and oxygen production rates, water transpiration rates, and biomass accumulation rates are obtained for comparison with ground-based data. In order to obtain an early realistic determination of the subsystem and system requirements necessary to provide the appropriate environmental conditions specified for CTF crop productivity experiments, an Engineering Development Unit (EDU) has been constructed and is undergoing initial operational testing at NASA Ames Research Center. The EDU is a ground-based testbed which will be used to characterize the integrated performance of major subsystem technologies, to evaluate hardware candidates and control strategies required for the CTF, and to further define the ability to meet CTF requirements within present Space Station constraints. This paper describes the initial closed operational testing of the EDU. Measured performance data are compared with the specified functional requirements and results from initial closed testing are presented. Plans for future science and technology testing are discussed.

Kliss, Mark↗

Generation of an Aerothermal Data Base for the X33 Spacecraft

The X-33 experimental program is a cooperative program between industry and NASA, managed by Lockheed-Martin Skunk Works to develop an experimental vehicle to demonstrate new technologies for a single-stage-to-orbit, fully reusable launch vehicle (RLV). One of the new technologies to be demonstrated is an advanced Thermal Protection System (TPS) being designed by BF Goodrich (formerly Rohr, Inc.) with support from NASA. The calculation of an aerothermal database is crucial to identifying the critical design environment data for the TPS. The NASA Ames X-33 team has generated such a database using Computational Fluid Dynamics (CFD) analyses, engineering analysis methods and various programs to compare and interpolate the results from the CFD and the engineering analyses. This database, along with a program used to query the database, is used extensively by several X-33 team members to help them in designing the X-33. This paper will describe the methods used to generate this database, the program used to query the database, and will show some of the aerothermal analysis results for the X-33 aircraft.

Roberts, Cathy↗