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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 577 records · Page 32

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NASA NTRS1981

Elliptical orbit performance computer program

A FORTRAN coded computer program which generates and plots elliptical orbit performance capability of space boosters for presentation purposes is described. Orbital performance capability of space boosters is typically presented as payload weight as a function of perigee and apogee altitudes. The parameters are derived from a parametric computer simulation of the booster flight which yields the payload weight as a function of velocity and altitude at insertion. The process of converting from velocity and altitude to apogee and perigee altitude and plotting the results as a function of payload weight is mechanized with the ELOPE program. The program theory, user instruction, input/output definitions, subroutine descriptions and detailed FORTRAN coding information are included.

Myler, T. R.↗

NASA NTRS1981

NEMAR plotting computer program

A FORTRAN coded computer program which generates CalComp plots of trajectory parameters is examined. The trajectory parameters are calculated and placed on a data file by the Near Earth Mission Analysis Routine computer program. The plot program accesses the data file and generates the plots as defined by inputs to the plot program. Program theory, user instructions, output definitions, subroutine descriptions and detailed FORTRAN coding information are included. Although this plot program utilizes a random access data file, a data file of the same type and formatted in 102 numbers per record could be generated by any computer program and used by this plot program.

Myler, T. R.↗

NASA NTRS1981

Moments of inclination error distribution computer program

A FORTRAN coded computer program is described which calculates orbital inclination error statistics using a closed-form solution. This solution uses a data base of trajectory errors from actual flights to predict the orbital inclination error statistics. The Scott flight history data base consists of orbit insertion errors in the trajectory parameters - altitude, velocity, flight path angle, flight azimuth, latitude and longitude. The methods used to generate the error statistics are of general interest since they have other applications. Program theory, user instructions, output definitions, subroutine descriptions and detailed FORTRAN coding information are included.

Myler, T. R.↗

NASA NTRS1981

PAN AIR: A computer program for predicting subsonic or supersonic linear potential flows about arbitrary configurations using a higher order panel method. Volume 4: Maintenance document (version 1.1)

The Maintenance Document is a guide to the PAN AIR software system, a system which computes the subsonic or supersonic linear potential flow about a body of nearly arbitrary shape, using a higher order panel method. The document describes the over-all system and each program module of the system. Sufficient detail is given for program maintenance, updating and modification. It is assumed that the reader is familiar with programming and CDC (Control Data Corporation) computer systems. The PAN AIR system was written in FORTRAN 4 language except for a few COMPASS language subroutines which exist in the PAN AIR library. Structured programming techniques were used to provide code documentation and maintainability. The operating systems accommodated are NOS 1.2, NOS/BE and SCOPE 2.1.3 on the CDC 6600, 7600 and Cyber 175 computing systems. The system is comprised of a data management system, a program library, an execution control module and nine separate FORTRAN technical modules. Each module calculates part of the posed PAN AIR problem. The data base manager is used to communicate between modules and within modules. The technical modules must be run in a prescribed fashion for each PAN AIR problem. In order to ease the problem of supplying the many JCL cards required to execute the modules, a separate module called MEC (Module Execution Control) was created to automatically supply most of the JCL cards. In addition to the MEC generated JCL, there is an additional set of user supplied JCL cards to initiate the JCL sequence stored on the system.

Baruah, P. K.↗

NASA NTRS1984

TEQUEL: The query language of SADDLE

A relational database management system is presented that is tailored for engineering applications. A wide variety of engineering data types are supported and the data definition language (DDL) and data manipulation language (DML) are extended to handle matrices. The system can be used either in the standalone mode or through a FORTRAN or PASCAL application program. The query language is of the relational calculus type and allows the user to store, retrieve, update and delete tuples from relations. The relational operations including union, intersect and differ facilitate creation of temporary relations that can be used for manipulating information in a powerful manner. Sample applications are shown to illustrate the creation of data through a FORTRAN program and data manipulation using the TEQUEL DML.

Rajan, S. D.↗

NASA NTRS1985

An investigation of vortex-induced aerodynamic characteristics of supersonic cruise configurations

The linear lifting surface theory which predicts the life in supersonic flow, even though the drag is usually underpredicted, is described. A method for calculating the nonlinear wave drag was developed to remedy this deficiency. The calculated sectional drag is modified by adding the difference between the exact two dimensional (2-D) and the linear 2-D wave drag at the calculated sectional lift coefficient. Improvement in the supersonic drag prediction is shown. The VORCAM code was modified for the FORTRAN 77 language and its input stream was rearranged. The Boeing code was adapted to the computer system. All CDC special features in the code are replaced with standard FORTRAN algorithms. It is suggested that because of the nonlinearity the solution appears to be nonunique crowding of two vortices, a mechanism of vortex asymmetry, is investigated.

Lan, C. E.↗

NASA NTRS1985

RATFOR user's guide version 2.0

This document is a user's guide for RATFOR at Ames Research Center. The main part of the document is a general description of RATFOR, and the appendix is devoted to a machine specific implementation for the Cray X-MP. The general stylistic features of RATFOR are discussed, including the block structure, keywords, source code, format, and the notion of tokens. There is a section on the basic control structures (IF-ELSE, ELSE IF, WHILE, FOR, DO, REPEAT-UNTIL, BREAK, NEXT), and there is a section on the statements that extend FORTRAN's capabilities (DEFINE, MACRO, INCLUDE, STRING). THE appendix discusses everything needed to compile and run a basic job, the preprocessor options, the supported character sets, the generated listings, fatal errors, and program limitations and the differences from standard FORTRAN.

Helmle, L. C.↗

NASA NTRS1982

Computer program for prediction of capture maneuver probability for an on-off reaction controlled upper stage

A FORTRAN coded computer program which computes the capture transient of a launch vehicle upper stage at the ignition and/or separation event is presented. It is for a single degree-of-freedom on-off reaction jet attitude control system. The Monte Carlo method is used to determine the statistical value of key parameters at the outcome of the event. Aerodynamic and booster induced disturbances, vehicle and control system characteristics, and initial conditions are treated as random variables. By appropriate selection of input data pitch, yaw and roll axes can be analyzed. Transient response of a single deterministic case can be computed. The program is currently set up on a CDC CYBER 175 computer system but is compatible with ANSI FORTRAN computer language. This routine has been used over the past fifteen (15) years for the SCOUT Launch Vehicle and has been run on RECOMP III, IBM 7090, IBM 360/370, CDC6600 and CDC CYBER 175 computers with little modification.

Knauber, R. N.↗

NASA NTRS1982

Computer program for post-flight analysis of rigid body moments acting on a launch vehicle first stage

A FORTRAN coded computer program and method for evaluation of the rigid body disturbing moments for a launch vehicle first stage based on post-flight measurements is described. The technique is a straightforward deterministic approach. Residual moments are computed to satisfy the equations of motion. Residuals are expressed in terms of altered vehicle characteristics; the aerodynamic coefficients, thrust misalignment, and control effectiveness. This method was used on the Scout launch vehicle and uncovered several significant differences between flight data and wind tunnel data. The computer program is written in FORTRAN IV for a CDC CYBER 173 computer system.

Knauber, R. N.↗

NASA NTRS1981

Longitudinal stability and control derivatives obtained from flight data of a PA-30 aircraft

In order to obtain reliable and accurate values of the stability and control derivatives, the Dryden Fligh Research Center (DFRC) developed a technique for extracting the derivatives from flight data. This technique is implemented by a set of FORTRAN computer programs that is based on a modified maximum likelihood estimator that uses the Newton-Raphson algorithm to perform the required minimization of the derivatives. Data was obtained with a PA-30, light twin-engine general aviation aircraft in zero, half, and full flap configuration in level unaccelerated flight with the landing gear retracted. The derivatives were plotted as functions of angle of attack using various graphical arrangements to show variations of wind tunnel and flight determined values at zero flap settings. Also, data was displayed to show the effects of flap deflection and thrust variation on the longitudinal stability derivatives. The angle of attack and angle of sideslip were measured. The dynamic pressure, velocity, and altitude were calculated, using a FORTRAN computer program, from the static and dynamic pressures. The control deflections of the stabilator, ailerons, and rudder also were recorded along with left throttle position, engine rpm, and manifold pressure.

Turley, D. R.↗

NASA NTRS1987

Control-System Design Program

Control-theory design package, Optimal Regulator Algorithms for Control of Linear Systems (ORACLS), developed to aid in design of controllers and optimal filters for systems modeled by linear, time-invariant differential and difference equations. Optimal linear quadratic regulator theory, Linear-Quadratic-Gaussian (LQG) problem, most widely accepted method of determining optimal control policy. Provides for solution to time-in-variant continuous or discrete LQG problems. Attractive to control-system designer providing rigorous tool for dealing with multi-input and multi-output dynamic systems in continuous and discrete form. CDO version written in FORTRAN IV. VAX version written in FORTRAN 77.

Frisch, Harold P.↗

NASA NTRS1986

Implementation of a data management software system for SSME test history data

The implementation of a software system for managing Space Shuttle Main Engine (SSME) test/flight historical data is presented. The software system uses the database management system RIM7 for primary data storage and routine data management, but includes several FORTRAN programs, described here, which provide customized access to the RIM7 database. The consolidation, modification, and transfer of data from the database THIST, to the RIM7 database THISRM is discussed. The RIM7 utility modules for generating some standard reports from THISRM and performing some routine updating and maintenance are briefly described. The FORTRAN accessing programs described include programs for initial loading of large data sets into the database, capturing data from files for database inclusion, and producing specialized statistical reports which cannot be provided by the RIM7 report generator utility. An expert system tutorial, constructed using the expert system shell product INSIGHT2, is described. Finally, a potential expert system, which would analyze data in the database, is outlined. This system could use INSIGHT2 as well and would take advantage of RIM7's compatibility with the microcomputer database system RBase 5000.

Abernethy, Kenneth↗

NASA NTRS1987

Force user's manual, revised

A methodology for writing parallel programs for shared memory multiprocessors has been formalized as an extension to the Fortran language and implemented as a macro preprocessor. The extended language is known as the Force, and this manual describes how to write Force programs and execute them on the Flexible Computer Corporation Flex/32, the Encore Multimax and the Sequent Balance computers. The parallel extension macros are described in detail, but knowledge of Fortran is assumed.

Jordan, Harry F.↗

NASA NTRS1987

The pEst version 2.1 user's manual

This report is a user's manual for version 2.1 of pEst, a FORTRAN 77 computer program for interactive parameter estimation in nonlinear dynamic systems. The pEst program allows the user complete generality in definig the nonlinear equations of motion used in the analysis. The equations of motion are specified by a set of FORTRAN subroutines; a set of routines for a general aircraft model is supplied with the program and is described in the report. The report also briefly discusses the scope of the parameter estimation problem the program addresses. The report gives detailed explanations of the purpose and usage of all available program commands and a description of the computational algorithms used in the program.

Murray, James E.↗

NASA NTRS1985

A software toolbox for robotics

A system of programs was developed to simulate the concurrent command/response interaction between a parallel jaw end effector and the LISP program controlling it. The overall structure of the simulation system was described in a paper submitted to the IEEE Conference on Automation and Robotics. A user's guide for the system was written. A line numbering program on the VAX (Pascal), a program for aiding in file transfer from the VAX to an LSI11 over the RTNET (FORTRAN), and a file scanning program (a crude SCAN) for the LSI11 (FORTRAN) were also developed.

Bynum, W. L.↗

NASA NTRS1988

Four-Dimensional Global Reference-Atmosphere Model

Four-Dimensional Global Reference Atmosphere Model (GRAM) computer program developed from empirical atmospheric model generating values for pressure, density, temperature, and winds, from ground to orbital altitudes. Is amalgamation of two empirical atmospheric models for low and high atmosphere with newly-developed latitude-and longitude-dependent model for middle atmosphere. UNIVAC version written in UNIVAC FORTRAN. DEC VAX version of GRAM written in FORTRAN 77. Applications include simulation of reentry trajectories of external tanks, studies of global circulation and diffusion and generation of plots or data for comparison.

Johnson, Dale↗

NASA NTRS1986

A performance comparison of the Cray-2 and the Cray X-MP

A suite of thirteen large Fortran benchmark codes were run on Cray-2 and Cray X-MP supercomputers. These codes were a mix of compute-intensive scientific application programs (mostly Computational Fluid Dynamics) and some special vectorized computation exercise programs. For the general class of programs tested on the Cray-2, most of which were not specially tuned for speed, the floating point operation rates varied under a variety of system load configurations from 40 percent up to 125 percent of X-MP performance rates. It is concluded that the Cray-2, in the original system configuration studied (without memory pseudo-banking) will run untuned Fortran code, on average, about 70 percent of X-MP speeds.

Schmickley, Ronald↗

NASA NTRS1988

Automatic mathematical modeling for real time simulation system

A methodology for automatic mathematical modeling and generating simulation models is described. The models will be verified by running in a test environment using standard profiles with the results compared against known results. The major objective is to create a user friendly environment for engineers to design, maintain, and verify their model and also automatically convert the mathematical model into conventional code for conventional computation. A demonstration program was designed for modeling the Space Shuttle Main Engine Simulation. It is written in LISP and MACSYMA and runs on a Symbolic 3670 Lisp Machine. The program provides a very friendly and well organized environment for engineers to build a knowledge base for base equations and general information. It contains an initial set of component process elements for the Space Shuttle Main Engine Simulation and a questionnaire that allows the engineer to answer a set of questions to specify a particular model. The system is then able to automatically generate the model and FORTRAN code. The future goal which is under construction is to download the FORTRAN code to VAX/VMS system for conventional computation. The SSME mathematical model will be verified in a test environment and the solution compared with the real data profile. The use of artificial intelligence techniques has shown that the process of the simulation modeling can be simplified.

Wang, Caroline↗