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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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All sourcesNASA NTRSDOE OSTI
NASA NTRS1988

Computer systems and software engineering

The High Technologies Laboratory (HTL) was established in the fall of 1982 at the University of Houston Clear Lake. Research conducted at the High Tech Lab is focused upon computer systems and software engineering. There is a strong emphasis on the interrelationship of these areas of technology and the United States' space program. In Jan. of 1987, NASA Headquarters announced the formation of its first research center dedicated to software engineering. Operated by the High Tech Lab, the Software Engineering Research Center (SERC) was formed at the University of Houston Clear Lake. The High Tech Lab/Software Engineering Research Center promotes cooperative research among government, industry, and academia to advance the edge-of-knowledge and the state-of-the-practice in key topics of computer systems and software engineering which are critical to NASA. The center also recommends appropriate actions, guidelines, standards, and policies to NASA in matters pertinent to the center's research. Results of the research conducted at the High Tech Lab/Software Engineering Research Center have given direction to many decisions made by NASA concerning the Space Station Program.

Mckay, Charles W.↗
NASA NTRS1998

Multidisciplinary Design Technology Development: A Comparative Investigation of Integrated Aerospace Vehicle Design Tools

This research effort is a joint program between the Departments of Aerospace and Mechanical Engineering and the Computer Science and Engineering Department at the University of Notre Dame. Three Principal Investigators; Drs. Renaud, Brockman and Batill directed this effort. During the four and a half year grant period, six Aerospace and Mechanical Engineering Ph.D. students and one Masters student received full or partial support, while four Computer Science and Engineering Ph.D. students and one Masters student were supported. During each of the summers up to four undergraduate students were involved in related research activities. The purpose of the project was to develop a framework and systematic methodology to facilitate the application of Multidisciplinary Design Optimization (N4DO) to a diverse class of system design problems. For all practical aerospace systems, the design of a systems is a complex sequence of events which integrates the activities of a variety of discipline "experts" and their associated "tools". The development, archiving and exchange of information between these individual experts is central to the design task and it is this information which provides the basis for these experts to make coordinated design decisions (i.e., compromises and trade-offs) - resulting in the final product design. Grant efforts focused on developing and evaluating frameworks for effective design coordination within a MDO environment. Central to these research efforts was the concept that the individual discipline "expert", using the most appropriate "tools" available and the most complete description of the system should be empowered to have the greatest impact on the design decisions and final design. This means that the overall process must be highly interactive and efficiently conducted if the resulting design is to be developed in a manner consistent with cost and time requirements. The methods developed as part of this research effort include; extensions to a sensitivity based Concurrent Subspace Optimization (CSSO) MDO algorithm; the development of a neural network response surface based CSSO-MDO algorithm; and the integration of distributed computing and process scheduling into the MDO environment. This report overviews research efforts in each of these focus. A complete bibliography of research produced with support of this grant is attached.

Renaud, John E.↗
NASA NTRS1989

Environmental concept for engineering software on MIMD computers

The issues related to developing an environment in which engineering systems can be implemented on MIMD machines are discussed. The problem is presented in terms of implementing the finite element method under such an environment. However, neither the concepts nor the prototype implementation environment are limited to this application. The topics discussed include: the ability to schedule and synchronize tasks efficiently; granularity of tasks; load balancing; and the use of a high level language to specify parallel constructs, manage data, and achieve portability. The objective of developing a virtual machine concept which incorporates solutions to the above issues leads to a design that can be mapped onto loosely coupled, tightly coupled, and hybrid systems.

Lopez, L. A.↗
NASA NTRS1995

Computational Simulation Of A Nuclear Engine

Nuclear Engine System Simulation (NESS) computer program developed to satisfy need for accurate, stand-alone software tool for preliminary design analysis of nuclear thermal propulsion (NTP) engine system. Used for rapid, preliminary detailed design analysis of both reactor and key engine systems. Principal outputs include operating characteristics and weights of reactors, engine-system parameters as performances, weights, dimensions, pressures, temperatures, and mass flows, and operating characteristics of turbopumps under both design and off-design operating conditions. Written in FORTRAN 77.

Walton, J. T.↗
NASA NTRS2014

Towards Test Driven Development for Computational Science with pFUnit

Developers working in Computational Science & Engineering (CSE)/High Performance Computing (HPC) must contend with constant change due to advances in computing technology and science. Test Driven Development (TDD) is a methodology that mitigates software development risks due to change at the cost of adding comprehensive and continuous testing to the development process. Testing frameworks tailored for CSE/HPC, like pFUnit, can lower the barriers to such testing, yet CSE software faces unique constraints foreign to the broader software engineering community. Effective testing of numerical software requires a comprehensive suite of oracles, i.e., use cases with known answers, as well as robust estimates for the unavoidable numerical errors associated with implementation with finite-precision arithmetic. At first glance these concerns often seem exceedingly challenging or even insurmountable for real-world scientific applications. However, we argue that this common perception is incorrect and driven by (1) a conflation between model validation and software verification and (2) the general tendency in the scientific community to develop relatively coarse-grained, large procedures that compound numerous algorithmic steps.We believe TDD can be applied routinely to numerical software if developers pursue fine-grained implementations that permit testing, neatly side-stepping concerns about needing nontrivial oracles as well as the accumulation of errors. We present an example of a successful, complex legacy CSE/HPC code whose development process shares some aspects with TDD, which we contrast with current and potential capabilities. A mix of our proposed methodology and framework support should enable everyday use of TDD by CSE-expert developers.

pFUnit↗
NASA NTRS1988

Calculations of the unsteady, three-dimensional flow field inside a motored Wankel engine

A computer program (referred to as UF-LRC-3D) was developed for studying the unsteady, three-dimensional flow field inside the combustion chambers of motored Wankel engines as a function of engine design and operating parameters. This paper presents the details of the governing equations and the numerical method used by UF-LRC-3D. Also presented are numerical solutions generated by UF-LRC-3D showing the velocity field inside a motored Wankel engine, the mixing of nonhomogeneous fuel-air mixtures that enter through the intake port, and the mixing that takes place when a gaseous fuel is injected into the combustion chamber during compression.

Steinthorsson, Erlendur↗
NASA NTRS1990

Software environment for implementing engineering applications on MIMD computers

In this paper the concept for a software environment for developing engineering application systems for multiprocessor hardware (MIMD) is presented. The philosophy employed is to solve the largest problems possible in a reasonable amount of time, rather than solve existing problems faster. In the proposed environment most of the problems concerning parallel computation and handling of large distributed data spaces are hidden from the application program developer, thereby facilitating the development of large-scale software applications. Applications developed under the environment can be executed on a variety of MIMD hardware; it protects the application software from the effects of a rapidly changing MIMD hardware technology.

Lopez, L. A.↗
NASA NTRS1996

Computer-Based Mathematics Instructions for Engineering Students

Almost every engineering course involves mathematics in one form or another. The analytical process of developing mathematical models is very important for engineering students. However, the computational process involved in the solution of some mathematical problems may be very tedious and time consuming. There is a significant amount of mathematical software such as Mathematica, Mathcad, and Maple designed to aid in the solution of these instructional problems. The use of these packages in classroom teaching can greatly enhance understanding, and save time. Integration of computer technology in mathematics classes, without de-emphasizing the traditional analytical aspects of teaching, has proven very successful and is becoming almost essential. Sample computer laboratory modules are developed for presentation in the classroom setting. This is accomplished through the use of overhead projectors linked to graphing calculators and computers. Model problems are carefully selected from different areas.

Khan, Mustaq A.↗
NASA NTRS2002

CAD/CAE Integration Enhanced by New CAD Services Standard

A Government-industry team led by the NASA Glenn Research Center has developed a computer interface standard for accessing data from computer-aided design (CAD) systems. The Object Management Group, an international computer standards organization, has adopted this CAD services standard. The new standard allows software (e.g., computer-aided engineering (CAE) and computer-aided manufacturing software to access multiple CAD systems through one programming interface. The interface is built on top of a distributed computing system called the Common Object Request Broker Architecture (CORBA). CORBA allows the CAD services software to operate in a distributed, heterogeneous computing environment.

Claus, Russell W.↗
NASA NTRS2014

Physics-based Entry, Descent and Landing Risk Model

A physics-based risk model was developed to assess the risk associated with thermal protection system failures during the entry, descent and landing phase of a manned spacecraft mission. In the model, entry trajectories were computed using a three-degree-of-freedom trajectory tool, the aerothermodynamic heating environment was computed using an engineering-level computational tool and the thermal response of the TPS material was modeled using a one-dimensional thermal response tool. The model was capable of modeling the effect of micrometeoroid and orbital debris impact damage on the TPS thermal response. A Monte Carlo analysis was used to determine the effects of uncertainties in the vehicle state at Entry Interface, aerothermodynamic heating and material properties on the performance of the TPS design. The failure criterion was set as a temperature limit at the bondline between the TPS and the underlying structure. Both direct computation and response surface approaches were used to compute the risk. The model was applied to a generic manned space capsule design. The effect of material property uncertainty and MMOD damage on risk of failure were analyzed. A comparison of the direct computation and response surface approach was undertaken.

descent and landing↗
NASA NTRS1993

Research in progress and other activities of the Institute for Computer Applications in Science and Engineering

This report summarizes research conducted at the Institute for Computer Applications in Science and Engineering in applied mathematics and computer science during the period April 1, 1993 through September 30, 1993. The major categories of the current ICASE research program are: (1) applied and numerical mathematics, including numerical analysis and algorithm development; (2) theoretical and computational research in fluid mechanics in selected areas of interest to LaRC, including acoustic and combustion; (3) experimental research in transition and turbulence and aerodynamics involving LaRC facilities and scientists; and (4) computer science.

Source record↗
NASA NTRS1997

Numerical Optimization Using Computer Experiments

Engineering design optimization often gives rise to problems in which expensive objective functions are minimized by derivative-free methods. We propose a method for solving such problems that synthesizes ideas from the numerical optimization and computer experiment literatures. Our approach relies on kriging known function values to construct a sequence of surrogate models of the objective function that are used to guide a grid search for a minimizer. Results from numerical experiments on a standard test problem are presented.

Trosset, Michael W.↗
NASA NTRS1986

Four-Cylinder Stirling Engine Control Simulation

Four-cylinder, Stirling-engine, transient-engine-simulation computer program developed. Program intended for control analysis. Associated engine model simplified to shorten computer calculation time. Model includes engine mechanical-drive dynamics and vehicle-load effects. Computer program also includes subroutines that allow acceleration of engine by addition of hydrogen to system and braking of engine by short circuiting of working spaces.

Daniele, C. J.↗