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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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Reference systems and transformations

The verification accomplished to assure correct computation of the many geometrical relationships between the several coordinate systems and transformation matrices defined for the Saturn 1B mission was discussed. This is accomplished by demonstrating the following: (1) the program has the ability to correctly establish the initial vector coordinate system from external input data for use as a reference, (2) the program logic is capable of properly executing the calculations necessary to transform vectorial parameters from one coordinate system to another, and (3) the presettings used for vector component calculations are valid.

Source record↗
NASA NTRS1975

Orbital Maneuvering Engine Feed System Coupled Stability Investigation, Computer User's Manual

An operating manual for the feed system coupled stability model was given, in partial fulfillment of a program designed to develop, verify, and document a digital computer model that can be used to analyze and predict engine/feed system coupled instabilities in pressure-fed storable propellant propulsion systems over a frequency range of 10 to 1,000 Hz. The first section describes the analytical approach to modelling the feed system hydrodynamics, combustion dynamics, chamber dynamics, and overall engineering model structure, and presents the governing equations in each of the technical areas. This is followed by the program user's guide, which is a complete description of the structure and operation of the computerized model. Last, appendices provide an alphabetized FORTRAN symbol table, detailed program logic diagrams, computer code listings, and sample case input and output data listings.

Schuman, M. D.↗
NASA NTRS1977

Aero-acoustic experimental verification of optimum configuration of variable-pitch fans for 40 x 80 foot subsonic wind tunnel

The aerodynamic and acoustic performance of two drive fan configurations (low-speed and high-speed variable pitch design) for a 40 x 80 foot wind tunnel were monitored. A 1/7-scale model was utilized. The necessary aero-acoustic data reduction computer program logic was supplied. Test results were evaluated, and the optimum configuration to be employed in the 40 foot full scale fan was recommended.

Lown, H.↗
NASA NTRS1981

Objective analysis of observational data from the FGGE observing systems

An objective analysis procedure for updating the GLAS second and fourth order general atmospheric circulation models using observational data from the first GARP global experiment is described. The objective analysis procedure is based on a successive corrections method and the model is updated in a data assimilation cycle. Preparation of the observational data for analysis and the objective analysis scheme are described. The organization of the program and description of the required data sets are presented. The program logic and detailed descriptions of each subroutine are given.

Baker, W.↗
NASA NTRS1981

Calculation of two-dimensional inlet flow fields by an implicit method including viscous effects: User's manual

Inlet flow fields for airbreathing missiles are calculated by the adaptation of a two dimensional computational method developed for the flow around airfoils. A supersonic free stream is assumed to allow the forebody calculation to be uncoupled from the inlet calculation. The inlet calculation employs an implicit, time marching finite difference procedure to solve the thin layer Navier-Stokes equations formulated in body fitted coordinates. The mathematical formulation of the problem and the solution algorithm are given. Numerical stability and accuracy as well as the initial and boundary conditions used are discussed. Instructions for program use and operation along with the overall program logic are also given.

Biringen, S.↗
NASA NTRS1981

Blade loss transient dynamics analysis, volume 2. Task 2: Theoretical and analytical development. Task 3: Experimental verification

The component element method was used to develop a transient dynamic analysis computer program which is essentially based on modal synthesis combined with a central, finite difference, numerical integration scheme. The methodology leads to a modular or building-block technique that is amenable to computer programming. To verify the analytical method, turbine engine transient response analysis (TETRA), was applied to two blade-out test vehicles that had been previously instrumented and tested. Comparison of the time dependent test data with those predicted by TETRA led to recommendations for refinement or extension of the analytical method to improve its accuracy and overcome its shortcomings. The development of working equations, their discretization, numerical solution scheme, the modular concept of engine modelling, the program logical structure and some illustrated results are discussed. The blade-loss test vehicles (rig full engine), the type of measured data, and the engine structural model are described.

Gallardo, V. C.↗
NASA NTRS1981

Blade loss transient dynamics analysis. Volume 3: User's manual for TETRA program

The users manual for TETRA contains program logic, flow charts, error messages, input sheets, modeling instructions, option descriptions, input variable descriptions, and demonstration problems. The process of obtaining a NASTRAN 17.5 generated modal input file for TETRA is also described with a worked sample.

Black, G. R.↗
NASA NTRS1982

Evaluation of automated decisionmaking methodologies and development of an integrated robotic system simulation. Volume 1: Study results

A variety of artificial intelligence techniques which could be used with regard to NASA space applications and robotics were evaluated. The techniques studied were decision tree manipulators, problem solvers, rule based systems, logic programming languages, representation language languages, and expert systems. The overall structure of a robotic simulation tool was defined and a framework for that tool developed. Nonlinear and linearized dynamics equations were formulated for n link manipulator configurations. A framework for the robotic simulation was established which uses validated manipulator component models connected according to a user defined configuration.

Lowrie, J. W.↗
NASA NTRS1986

Towards a science of expert systems

Developments in the field of AI are discussed. The components and applications of expert systems, which are computer systems designed to simulate the problem-solving behavior of a person expert in a narrow field, are examined. Two types of expert systems, shallow and deep, are described and examples are given. A logic programming system, rule-based system, and framed-based system are utilized as means of representing the expert system's data base. The limitations of expert systems are considered.

Denning, P. J.↗
NASA NTRS1986

A rule based computer aided design system

A Computer Aided Design (CAD) system is presented which supports the iterative process of design, the dimensional continuity between mating parts, and the hierarchical structure of the parts in their assembled configuration. Prolog, an interactive logic programming language, is used to represent and interpret the data base. The solid geometry representing the parts is defined in parameterized form using the swept volume method. The system is demonstrated with a design of a spring piston.

Premack, T.↗
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 NTRS1986

Evaluation of automated decisionmaking methodologies and development of an integrated robotic system simulation. Appendix B: ROBSIM programmer's guide

The purpose of the Robotic 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 FORTRAM 77 and implemented on a VAX 11/750 computer using the VMS operating system. The programmer's guide describes the ROBSIM implementation and program logic flow, and the functions and structures of the different subroutines. With the manual and the in-code documentation, an experienced programmer can incorporate additional routines and modify existing ones to add desired capabilities.

Haley, D. C.↗
NASA NTRS1987

SOLON: An autonomous vehicle mission planner

The State-Operator Logic Machine (SOLON) Planner provides an architecture for effective real-time planning and replanning for an autonomous vehicle. The highlights of the system, which distinguish it from other AI-based planners that have been designed previously, are its hybrid application of state-driven control architecture and the use of both schematic representations and logic programming for the management of its knowledge base. SOLON is designed to provide multiple levels of planning for a single autonomous vehicle which is supplied with a skeletal, partially-specified mission plan at the outset of the vehicle's operations. This mission plan consists of a set of objectives, each of which will be decomposable by the planner into tasks. These tasks are themselves comparatively complex sets of actions which are executable by a conventional real-time control system which does not perform planning but which is capable of making adjustments or modifications to the provided tasks according to constraints and tolerances provided by the Planner. The current implementation of the SOLON is in the form of a real-time simulation of the Planner module of an Intelligent Vehicle Controller (IVC) on-board an autonomous underwater vehicle (AUV). The simulation is embedded within a larger simulator environment known as ICDS (Intelligent Controller Development System) operating on a Symbolics 3645/75 computer.

Dudziak, M. J.↗
NASA NTRS1990

Computer program to solve two-dimensional shock-wave interference problems with an equilibrium chemically reacting air model

The computer program EASI, an acronym for Equilibrium Air Shock Interference, was developed to calculate the inviscid flowfield, the maximum surface pressure, and the maximum heat flux produced by six shock wave interference patterns on a 2-D, cylindrical configuration. Thermodynamic properties of the inviscid flowfield are determined using either an 11-specie, 7-reaction equilibrium chemically reacting air model or a calorically perfect air model. The inviscid flowfield is solved using the integral form of the conservation equations. Surface heating calculations at the impingement point for the equilibrium chemically reacting air model use variable transport properties and specific heat. However, for the calorically perfect air model, heating rate calculations use a constant Prandtl number. Sample calculations of the six shock wave interference patterns, a listing of the computer program, and flowcharts of the programming logic are included.

Glass, Christopher E.↗
NASA NTRS1992

A PC-based collapse factor analysis for high pressure cryogenic systems

A collapse factor simulation computer program, suitable for use on personal computers, for supercritical cryogen system pressurization is examined. The available literature is previewed, individual component models are developed, and the overall simulation program logic is examined. Extensive use is made of existing thermodynamic and transport property evaluation packages. Heat transfer is estimated using natural convection correlations, and transient wall heat conduction is considered. Examples of the simulation are demonstrated for two facilities. Partial validation is achieved by comparing the simulation output with data from an existing test facility. Preliminary results indicate that the collapse factors will seldom exceed 1.15 during supercritical operation of high-pressure cryogenic systems. Recommendations for improvements in the component models and the simulation are made.

Hodge, B. K.↗
NASA NTRS1992

An interactive preprocessor for the NASA engine performance program

The Simplified NEPP Automated Preprocessor (SNAP), which is written to aid in the preparation of input data files for the NASA Engine Performance Program (NEPP), is described. Specifically, SNAP is a software package on the Virtual Machine operating system that prompts the NEPP user for input information via a series of menus. The data collected from these menus are assimilated into an input file suitable for the running of NEPP. SNAP acts as a user-friendly preprocessing interface for NEPP. This serves as an introduction to the SNAP software, a user's manual, a description of the program logic, and a maintenance manual for future modifications to the software.

Berton, Jeffrey J.↗
NASA NTRS1992

Global planning of several plants

This paper discusses an attempt to solve the problem of planning several pharmaceutical plants at a global level. The interest in planning at this level is to increase the global control over the production process, to improve its overall efficiency, and to reduce the need for interaction between production plants. In order to reduce the complexity of this problem and to make it tractable, some abstractions were made. Based on these abstractions, a prototype is being developed within the framework of the EUREKA project PROTOS, using Constraint Logic Programming techniques.

Bescos, Sylvie↗