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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

SAMMY Modernization Efforts [Slides]

This presentation discusses SAMMY releases and states that all of its dependencies are freely available. It also discusses version control and confirms that versions will be tagged as needed. Additionally, SAMMY program flow is discussed and states that the program flow was improved to allow for easier external access to SAMMY routines. Modernization of SAMMY is continued with the Doppler and Resolution broadening modules. The presentation concludes by stating that documentation updates are in progress.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
NASA NTRS1979

A computerized method for calculating flutter characteristics of a system characterized by two degrees of freedom

A formulation is given for calculating flutter frequency and flutter speed for a problem with two degrees of freedom. Two different solutions for evaluating the flutter determinant are presented and the results for each method are compared. A program flow diagram, partial program listing, and a sample problem with input and output for the two different methods are included. Although the method was developed for computing flutter characteristics of a pylon installed in the NASA Langley VSTOL tunnel, it is sufficiently general to solve any flutter system that can be characterized by two degrees of freedom.

Stalnaker, W. A.↗
NASA NTRS1994

Update: NASA Pyrotechnically Actuated Systems Program

This technical report discusses the NASA Pyrotechnically Actuated Systems (PAS) Program. It contains the following three sections: program origin, program description, and summary. The first section, program origin, contains an introduction to pyrotechnic systems and devices and discusses some examples. Section two focuses on the PAS program goals, program flow, and PAS programs organization. And section three gives a overall summary of the program.

Schulze, Norman R.↗
NASA NTRS2022

Low-Speed Performance Enhancement using Localized Active Flow Control: Program Overview and Summary (1/4)

The Boeing team executed a NASA task order, titled “Low Speed Performance Enhancement using Localized Active Flow Control”, under the BAART framework NNL16AA04B, contract number 80LARC20F0082. The project was executed from Sept. 2020 through April 2022 with the objective to explore localized active flow control (AFC) concepts on a representative commercial aircraft. A detailed literature review solidified the choice of AFC concepts to be explored, including AFC over a deflected aileron, in the leading edge region of the wing, and in the nacelle/pylon/wing region. All three concepts were investigated with numerical tools. The results were used in an integration study to assess the net benefits over the lifetime of a commercial aircraft. The aerodynamic studies concluded that AFC applied over a deflected aileron yields significant net L/D improvements (incl. the penalty of AFC system requirements) of up to potentially 5% L/D. Depending on the configuration, AFC applied in the leading edge region showed improvements in L/D of up to ~1.5%, as well as opportunities for maximum lift and increased lift at fixed angle of attack. AFC applied to the nacelle/pylon/wing region delivered 1.5% increase in L/D during take-off and ~4% increase in CLmax during landing. After considering assumed onboard sources, aspects of system integration and weight penalties, these aerodynamic improvements translate to: ~ 0.5% block fuel reduction potential for AFC over the aileron ~ 0.1% block fuel reduction potential for AFC in the LE slat region ~ 0.2% block fuel reduction potential for AFC in the nacelle/pylon/wing region considering take-off scenarios (potentially larger benefit may be realized considering the landing scenarios which haven’t been fully analyzed yet) The final report is comprised of four separate documents. The current document provides an overview and technical background. The second document details the numerical studies and the third document summarizes the integration and aircraft performance assessment. The fourth document focuses on the Common Research Model, specifically how AFC performs over a deflected aileron and how the NASA 10% scale wind tunnel model may be modified to implement an AFC equipped aileron. Each report offers significantly more detailed summaries and suggestions for future work.

Active flow control↗
NASA NTRS1974

Manual for source flow characteristics program

A computer program for analyzing the nozzle for a hypersonic scramjet by a second order characteristic procedure is described. The program used FORTRAN IV. The input routine is provided. A sample input for a source flow case is included.

Kalben, P. P.↗
NASA NTRS1986

Program for Heat Flow in Welding

Program contains numerical model of temperature distribution in vicinity of weld. Weld model used to produce estimated welding power requirements, welding-power-loss analysis, heat-affected-zone temperature history, and weld-puddle cross-section plots. Applied to gas/tungsten-arc, plasma-arc, electron-beam, and laser-beam welds on wide plates under steady conditions. User predicts power requirements and temperature distributions. Weld model written in BASIC.

Nunes, A. C., Jr.↗
NASA NTRS1991

Development of an analytical tool to study power quality of AC power systems for large spacecraft

A harmonic power flow program applicable to space power systems with sources of harmonic distortion is described. The algorithm is a modification of the Electric Power Research Institute's HARMFLO program which assumes a three phase, balanced, AC system with loads of harmonic distortion. The modified power flow program can be used with single phase, AC systems. Early results indicate that the required modifications and the models developed are quite adequate for the analysis of a 20 kHz testbed built by General Dynamics Corporation. This is demonstrated by the acceptable correlation of present results with published data. Although the results are not exact, the discrepancies are relatively small.

Kraft, L. Alan↗
NASA NTRS1986

Vortical Flows Research Program of the Fluid Dynamics Research Branch

The research interests of the staff of the Fluid Dynamics Research Branch in the general area of vortex flows are summarized. A major factor in the development of enchanced maneuverability and reduced drag by aerodynamic means is the use of effective vortex control devices. The key to control is the use of emerging computational tools for predicting viscous fluid flow in close coordination with fundamental experiments. In fact, the extremely complex flow fields resulting from numerical solutions to boundary value problems based on the Navier-Stokes equations requires an intimate relationship between computation and experiment. The field of vortex flows is important in so many practical areas that a concerted effort in this area is justified. A brief background of the research activity undertaken is presented, including a proposed classification of the research areas. The classification makes a distinction between issues related to vortex formation and structure, and work on vortex interactions and evolution. Examples of current research results are provided, along with references where available. Based upon the current status of research and planning, speculation on future research directions of the group is also given.

Source record↗
NASA NTRS1991

Development of an analytical tool to study power quality of ac power systems for large spacecraft

A harmonic power flow program applicable to space power systems with sources of harmonic distortion is described. The algorithm is a modification of Electric Power Research Institute's HARMFLO program which assumes a three-phase, balanced, ac system with loads of harmonic distortion. The modified power flow program can be used with single phase, ac systems. Early results indicate that the required modifications and the models developed are quite adequate for the analysis of a 20-kHz testbed built by General Dynamics Corporation. This is demonstrated by the acceptable correlation of the present results with published data. Although the results are not exact, the discrepancies are relatively small.

Kraft, L. A.↗
NASA NTRS1983

Transient upset models in computer systems

Essential factors for the design of transient upset monitors for computers are discussed. The upset is a system level event that is software dependent. It can occur in the program flow, the opcode set, the opcode address domain, the read address domain, and the write address domain. Most upsets are in the program flow. It is shown that simple, external monitors functioning transparently relative to the system operations can be built if a detailed accounting is made of the characteristics of the faults that can happen. Sample applications are provided for different states of the Z-80 and 8085 based system.

Mason, G. M.↗
NASA NTRS1973

Computer program for the prediction of reorientation flow dynamics

Program uses Navier-Stokes and continuity equations for incompressible, viscous fluid as the basic equations governing reorientation flow dynamics. Program can simulate curved as well as straight-walled boundaries; has ability to calculate both free-surface and confined flows; and can be used in either cylindrical or plane geometry.

Betts, W. S., Jr.↗
NASA NTRS1993

Program Computes Flows Of Fluids And Heat

SINDA'85/FLUINT incorporates lumped-parameter-network and one-dimensional-flow mathematical models. System enables analysis of mutual influences of thermal and flow phenomena. Offers two finite-difference numerical solution techniques: forward-difference explicit approximation and Crank-Nicholson approximation. Enables simulation of nonuniform heating and facilitates mathematical modeling of thin-walled heat exchangers. Ability to model nonequilibrium behavior within two-phase volumes included. Recent changes in program improve modeling of real evaporator pumps and other capillary-assist evaporators. Written in FORTRAN 77.

Cullimore, Brent↗
NASA NTRS1986

Operational considerations for laminar flow aircraft

Considerable progress has been made in the development of laminar flow technology for commercial transports during the NASA Aircraft Energy Efficiency (ACEE) laminar flow program. Practical, operational laminar flow control (LFC) systems have been designed, fabricated, and are undergoing flight testing. New materials, fabrication methods, analysis techniques, and design concepts were developed and show much promise. The laminar flow control systems now being flight tested on the NASA Jetstar aircraft are complemented by natural laminar flow flight tests to be accomplished with the F-14 variable-sweep transition flight experiment. An overview of some operational aspects of this exciting program is given.

Maddalon, Dal V.↗
DOE OSTI2023

ERSAP: Toward Better NP Data-Stream Analytics With Flow-Based Programming

This paper presents an reactive, actor-model and FBP paradigm based framework that we develop to design data-stream processing applications for HEP and NP. This framework encourages a functional decomposition of the overall data processing application into small mono-functional artifacts. Artifacts that are easy to understand, develop, deploy and debug. The fact that these artifacts (actors) are programmatically independent they can be scaled and optimized independently, which is impossible to do for components of the monolithic application. One of the important advantages of this approach is fault tolerance where independent actors can come and go on the data-stream without forcing the entire application to crash. Furthermore, it also makes it is easy to locate the faulty actor in the data pipeline. Due the fact that the actors are loosely coupled, and that the data (inevitably) carries the context, they can run on heterogeneous environments, utilizing different accelerators. This paper describes the main design concepts of the framework and presents a ?proof of concept? application design and deployment results obtain processing on-beam calorimeter streaming data.

Gyurjyan, V.↗
NASA NTRS1972

Prediction of unsteady aerodynamic loadings caused by trailing edge control surface motions in subsonic compressible flow: Computer program description

A digital computer program has been developed to calculate unsteady loadings caused by motions of lifting surfaces with trailing edge control based on the subsonic kernal function approach. The pressure singularities at hinge line and side edges have been extracted analytically as a preliminary step to solving the integral by collocation. The program calculates generalized aerodynamic forces for user supplied deflection modes. Optional intermediate output includes pressure at an array of points, and sectional generalized forces. From one to four controls on the half span can be accommodated.

Redman, M. C.↗