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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 559 records · Page 31

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NASA NTRS1974

Separated flow over bodies of revolution using an unsteady discrete-vorticity cross wake. Part 2: Computer program description

A method is developed to determine the flow field of a body of revolution in separated flow. The computer was used to integrate various solutions and solution properties of the sub-flow fields which made up the entire flow field without resorting to a finite difference solution to the complete Navier-Stokes equations. The technique entails the use of the unsteady cross flow analogy and a new solution to the two-dimensional unsteady separated flow problem based upon an unsteady, discrete-vorticity wake. Data for the forces and moments on aerodynamic bodies at low speeds and high angle of attack (outside the range of linear inviscid theories) such that the flow is substantially separated are produced which compare well with experimental data. In addition, three dimensional steady separated regions and wake vortex patterns are determined. The computer program developed to perform the numerical calculations is described.

Marshall, F. J.↗

NASA NTRS1973

Digital flight control software design requirements

The objective of the integrated digital flight control system is to provide rotational and translational control of the space shuttle orbiter in all phases of flight: from launch ascent through orbit to entry and touchdown, and during powered horizontal flights. The program provides a versatile control system structure while maintaining uniform communications with other programs, sensors, and control effects by using an executive routine/function subroutine format. The program reads all external variables at a single point, copies them into its dedicated storage, and then calls the required subroutines in the proper sequence. As a result, the flight control program is largely independent of other programs in the GN and C computer complex and is equally insensitive to the characteristics of the processor configuration. The integrated structure of the control system and the DFCS executive routine which embodies that structure are described. The specific estimation and control algorithms used in the various mission phases are shown. Attitude maneuver routines that interface with the DFCS are also described.

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DOE OSTI2024

Revolutionizing Neuromorphic Computing for Science (Brochure on the 2024 ASCR Workshop on Neuromorphic Computing for Science)

The ASCR basic research needs for Neuromorphic Computing for Science workshop was held in September 2024. The workshop brochure and report aim to inform and draft a set of grand challenges for advancing the field of neuromorphic computing and developing proof of principle neuromorphic circuits applicable for High Performance Computer (HPC) acceleration for scientific discovery, and brainstorm ideas needed for a successful, robust, and world leading basic research program. The resulting priority research directions are: (1) Neuromorphic computing circuit primitives; (2) Connectivity, communication, and hardware integration; (3) Neuroscience-derived dynamics and algorithms; and (4) Ecosystem for scalable neuromorphic co-design. Breakthroughs in understanding, designing, and prototyping the circuitry and simulation capabilities for a truly neuromorphic computer are essential to enable progress in the field.

97 MATHEMATICS AND COMPUTING↗

DOE OSTI2024

Revolutionizing Neuromorphic Computing for Science (Report for the 2024 ASCR Workshop on Neuromorphic Computing for Science)

97 MATHEMATICS AND COMPUTING↗

DOE OSTI2026

IMPACT 2025-2026 Internship Poster

At Sandia National Laboratories, I developed a C++ program that converts printed circuit boards(PCB) and integrated circuits(IC) design files to be compatible for computed tomography (CT) simulations through Monte Carlo methods.

97 MATHEMATICS AND COMPUTING↗

NASA NTRS1963

Orbit determination and prediction, and computer programs

Orbit determination and prediction programs are needed to generate ephemerides for the satellite. Orbit determination is from tracking data consisting of angles only, and is based on a modified version of a method by R. E. Briggs and J. W. Slowey of the Smithsonian Institution. Trends in the data due to perturbations from a Keplerian orbit are removed before this process, and estimates of the orbital elements from individual passes are combined statistically to produce refined estimates. Ephemeris calculation is by a semi-analytic method in which deviations from a Keplerian orbit are obtained by integrating the perturbing forces. The programs to implement these procedures have been written for both the IBM 7090 and the IBM 1620 computers.

EPHEMERIS↗

NASA NTRS1976

Study of operational parameters impacting helicopter fuel consumption

A computerized study of operational parameters affecting helicopter fuel consumption was conducted as an integral part of the NASA Civil Helicopter Technology Program. The study utilized the Helicopter Sizing and Performance Computer Program (HESCOMP) developed by the Boeing-Vertol Company and NASA Ames Research Center. An introduction to HESCOMP is incorporated in this report. The results presented were calculated using the NASA CH-53 civil helicopter research aircraft specifications. Plots from which optimum flight conditions for minimum fuel use that can be obtained are presented for this aircraft. The results of the study are considered to be generally indicative of trends for all helicopters.

Cross, J. L.↗

NASA NTRS1982

Aerodynamics of Supersonic Aircraft

An integrated system for the analysis of supersonic configurations consists of an executive driver and eight basic computer programs that build up force coefficients of an selected configuration. System employs modified linearized theory for calculation of surface pressures and employs supersonic-area-rule concepts in combination with linearized theory for calculation of aerodynamic force coefficients.

Middleton, W. D.↗

NASA NTRS1981

Coronal observations from the SMM satellite

The scientific purpose, coronal observations, and the instrument design and control of the Coronagraph/Polarimeter aboard the Solar Maximum Mission (SMM) satellite are discussed. The instruments were made with an optical design using an achromatic objective lens providing a 10 arcsec resolution in imaging and an SEC vidicon detector allowing integration on the low light levels of the corona. The computer control assures flexibility in the observing program to optimize observations of changing solar phenomena and allows rapid response to SMM or ground-commanded solar flare alerts.

Csoeke-Poeckh, A.↗

NASA NTRS1982

A study of microwave downcoverters operating in the K sub u band

A computer program for parametric amplifier design is developed with special emphasis on practical design considerations for microwave integrated circuit degenerate amplifiers. Precision measurement techniques are developed to obtain a more realistic varactor equivalent circuit. The existing theory of a parametric amplifier is modified to include the equivalent circuit, and microwave properties, such as loss characteristics and circuit discontinuities are investigated.

Fellers, R. G.↗

NASA NTRS1981

Development of advanced Czochralski growth process to produce low cost 150 kg silicon ingots from a single crucible for technology readiness

The process development continued, with a total of nine crystal growth runs. One of these was a 150 kg run of 5 crystals of approximately 30 kg each. Several machine and process problems were corrected and the 150 kg run was as successful as previous long runs on CG2000 RC's. The accelerated recharge and growth will be attempted when the development program resumes at full capacity in FY '82. The automation controls (Automatic Grower Light Computer System) were integrated to the seed dip temperature, shoulder, and diameter sensors on the CG2000 RC development grower. Test growths included four crystals, which were grown by the computer/sensor system from seed dip through tail off. This system will be integrated on the Mod CG2000 grower during the next quarter. The analytical task included the completion and preliminary testing of the gas chromatograph portion of the Furnace Atmosphere Analysis System. The system can detect CO concentrations and will be expanded to oxygen and water analysis in FY '82.

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NASA NTRS1985

Theoretical analysis of linearized acoustics and aerodynamics of advanced supersonic propellers

The derivation of a formula for prediction of the noise of supersonic propellers using time domain analysis is presented. This formula is a solution of the Ffowcs Williams-Hawkings equation and does not have the Doppler singularity of some other formulations. The result presented involves some surface integrals over the blade and line integrals over the leading and trailing edges. The blade geometry, motion and surface pressure are needed for noise calculation. To obtain the blade surface pressure, the observer is moved onto the blade surface and a linear singular integral equation is derived which can be solved numerically. Two examples of acoustic calculations using a computer program are currently under development.

Farassat, F.↗

NASA NTRS1984

Evaluation of automated decisionmaking methodologies and development of an integrated robotic system simulation, appendix B

The purpose of the Robotics Simulation (ROBSIM) program is to provide a broad range of computer capabilities to assist in the design, verification, simulation, and study of robotic systems. ROBSIM is programmed in FORTRAN 77 and implemented on a VAX 11/750 computer using the VMS operating system. This programmer's guide describes the ROBSIM implementation and program logic flow, and the functions and structures of the different subroutines. With this manual and the in-code documentation, and experienced programmer can incorporate additional routines and modify existing ones to add desired capabilities.

Haley, D. C.↗

NASA NTRS1989

Numerical modeling of turbulent supersonic reacting coaxial jets

The paper considers the mixing and subsequent combustion within turbulent reacting shear layers. A computer program was developed to solve the axisymmetric Reynolds averaged Navier-Stokes equations. The numerical method integrates the Reynolds averaged Navier-Stokes equations using a finite volume approach while advancing the solution forward in time using a Runge-Kutta scheme. Three separate flowfields are investigated and it is found that no single turbulence model considered could accurately predict the degree of mixing for all three cases.

Eklund, Dean R.↗

NASA NTRS1990

Parallel processors and nonlinear structural dynamics algorithms and software

Techniques are discussed for the implementation and improvement of vectorization and concurrency in nonlinear explicit structural finite element codes. In explicit integration methods, the computation of the element internal force vector consumes the bulk of the computer time. The program can be efficiently vectorized by subdividing the elements into blocks and executing all computations in vector mode. The structuring of elements into blocks also provides a convenient way to implement concurrency by creating tasks which can be assigned to available processors for evaluation. The techniques were implemented in a 3-D nonlinear program with one-point quadrature shell elements. Concurrency and vectorization were first implemented in a single time step version of the program. Techniques were developed to minimize processor idle time and to select the optimal vector length. A comparison of run times between the program executed in scalar, serial mode and the fully vectorized code executed concurrently using eight processors shows speed-ups of over 25. Conjugate gradient methods for solving nonlinear algebraic equations are also readily adapted to a parallel environment. A new technique for improving convergence properties of conjugate gradients in nonlinear problems is developed in conjunction with other techniques such as diagonal scaling. A significant reduction in the number of iterations required for convergence is shown for a statically loaded rigid bar suspended by three equally spaced springs.

Belytschko, Ted↗

NASA NTRS1992

Program Assists Design Of Cabling

DFACS is interactive, multiuser, computer-aided-engineering software tool for system-level electrical-integration and cabling engineering. Purpose to provide engineering community with centralized data base for entering and gaining access to definitions of functions of systems, details of pin connections to circuits at subsystem and instrument ends and data on harnessing of cables. Primary objective provides instantaneous single point of interchange of information, avoiding error-prone, time-consuming, and costly multiple-path shuttling of data.

Billitti, Joseph W.↗

NASA NTRS1994

Man-machine Integration Design and Analysis System (MIDAS) Task Loading Model (TLM) experimental and software detailed design report

This is the experimental and software detailed design report for the prototype task loading model (TLM) developed as part of the man-machine integration design and analysis system (MIDAS), as implemented and tested in phase 6 of the Army-NASA Aircrew/Aircraft Integration (A3I) Program. The A3I program is an exploratory development effort to advance the capabilities and use of computational representations of human performance and behavior in the design, synthesis, and analysis of manned systems. The MIDAS TLM computationally models the demands designs impose on operators to aide engineers in the conceptual design of aircraft crewstations. This report describes TLM and the results of a series of experiments which were run this phase to test its capabilities as a predictive task demand modeling tool. Specifically, it includes discussions of: the inputs and outputs of TLM, the theories underlying it, the results of the test experiments, the use of the TLM as both stand alone tool and part of a complete human operator simulation, and a brief introduction to the TLM software design.

Staveland, Lowell↗

NASA NTRS1999

Multidisciplinary Optimization Branch Experience Using iSIGHT Software

The Multidisciplinary Optimization (MDO) Branch at NASA Langley Research Center is investigating frameworks for supporting multidisciplinary analysis and optimization research. An optimization framework call improve the design process while reducing time and costs. A framework provides software and system services to integrate computational tasks and allows the researcher to concentrate more on the application and less on the programming details. A framework also provides a common working environment and a full range of optimization tools, and so increases the productivity of multidisciplinary research teams. Finally, a framework enables staff members to develop applications for use by disciplinary experts in other organizations. Since the release of version 4.0, the MDO Branch has gained experience with the iSIGHT framework developed by Engineous Software, Inc. This paper describes experiences with four aerospace applications: (1) reusable launch vehicle sizing, (2) aerospike nozzle design, (3) low-noise rotorcraft trajectories, and (4) acoustic liner design. All applications have been successfully tested using the iSIGHT framework, except for the aerospike nozzle problem, which is in progress. Brief overviews of each problem are provided. The problem descriptions include the number and type of disciplinary codes, as well as all estimate of the multidisciplinary analysis execution time. In addition, the optimization methods, objective functions, design variables, and design constraints are described for each problem. Discussions on the experience gained and lessons learned are provided for each problem. These discussions include the advantages and disadvantages of using the iSIGHT framework for each case as well as the ease of use of various advanced features. Potential areas of improvement are identified.

Padula, S. L.↗