Showing papers on "Performance prediction published in 1978"

A digital computer program for the dynamic interaction simulation of controls and structure (DISCOS), volume 1

Abstract: A theoretical development and associated digital computer program system for the dynamic simulation and stability analysis of passive and actively controlled spacecraft are presented The dynamic system (spacecraft) is modeled as an assembly of rigid and/or flexible bodies not necessarily in a topological tree configuration The computer program system is used to investigate total system dynamic characteristics, including interaction effects between rigid and/or flexible bodies, control systems, and a wide range of environmental loadings In addition, the program system is used for designing attitude control systems and for evaluating total dynamic system performance, including time domain response and frequency domain stability analyses

Delta method, an empirical drag buildup technique

Abstract: An empirical drag correlation technique was developed from analysis of 19 subsonic and supersonic military aircraft and 15 advanced or supercritical airfoil configurations which can be applied in conceptual and advanced aircraft design activities. The Delta Method may be used for estimating the clean wing drag polar for cruise and maneuver conditions up to buffet onset, and to approximately Mach 2.0. This technique incorporates a unique capability of predicting the off-design performance of advanced or supercritical airfoil sections. The buffet onset limit may also be estimated. The method is applicable to wind tunnel models as well as to full scale configurations. This technique has been converted into a computer code for use on the IBM 360 and CDC 7600 computer facilities at NASA AMES. Results obtained using this method to predict known aircraft characteristics are good and agreement can be obtained within a degree of accuracy judged to be sufficient for the initial processes of preliminary design.

A Numerical Technique for SAW Diffraction Simulation

Abstract: An efficient numerical technique is presented for simulating the effect of diffraction on the performance of surface acoustic wave (SAW) devices. A computer code based on this technique accurately predicts the performance of several "practical" bandpass filters fabricated on ST-cut quartz. Since the algorithm is fast, an iterative design procedure which minimizes the frequency sidelobes in the presence of diffraction is now practical.

PECAL: A New Computer Program for the EMC Performance Evaluation of Communication Systems in a Cosite Configuration

Abstract: A computer program (PECAL) is described which pre­ dicts the performance of multiple EM communication equipments in the 2 to 400 MHz band when placed in a Navy shipboard (single-ship) configuration. A com­ bination of linear and nonlinear interference phenom­ ena are analyzed. The scope of the program is limited to the treatment of interference mechanisms involving radiated, antenna coupled signals and multicoupler crosstalk signals. The EMC performance measures are expressed in terms of statistics, as are many of the model parameters used in the interference prediction equations.

SIMWEST - A simulation model for wind energy storage systems

Abstract: This paper describes a comprehensive and efficient computer program for the modeling of wind energy systems with storage. The level of detail of SIMWEST (SImulation Model for Wind Energy STorage) is consistent with evaluating the economic feasibility as well as the general performance of wind energy systems with energy storage options. The software package consists of two basic programs and a library of system, environmental, and control components. The first program is a precompiler which allows the library components to be put together in building block form. The second program performs the technoeconomic system analysis with the required input/output, and the integration of system dynamics. An example of the application of the SIMWEST program to a current 100 kW wind energy storage system is given.

Simple technique of estimating the performance of passive solar heating systems

Abstract: A method is presented for estimating the annual solar performance of a building using a passive thermal storage wall of the Trombe wall or water wall type with or without night insulation Tables of performance parameters are given for 84 cities The method is accurate to +-3% as compared with hour-by-hour computer simulations

Performance Evaluation of Communication Channels by Computer Simulation

Abstract: A computer simulation model capable of aiding in the design and predicting the performance of complex end-to-end communication systems is described in this paper. The model is used to choose the optimal modulation scheme under certain communication channel constraints, define the signal distortion characteristics introduced by realizable channel components and select the demodulator/bit synchronizer designs for minimization of bit error rate. A parameter sensitivity analysis is conducted to demonstrate the usefulness of the model in evaluating the effect of different signal distortion phenomena on overall link performance.

Performance prediction of floating drilling vessels for various operating areas

Abstract: This paper describes a computer program, composed of weather and drilling models, that was developed to help select floating drilling vessels for specific operating areas and start-up times. With these models, expected performance of different vessels can be simulated and their costs compared. Brief discussions are given on the types of information needed and the concepts used in these models.

Simulation and cost of photovoltaic generators

Abstract: A simulation model of photovoltaic generators is presented. Electrical production, investment and operation costs can be easily estimated for a given generator configuration. The user has to specify meteorological conditions, generator size and structure, along with time variations of the power demand. A computer program simulates operation of the complete system and provides data to evaluate its electrical and economical performance. This computer program is described. In order to illustrate the model capabilities, preliminary results are also presented. First example concerns a classical AC photovoltaic generator (flat panels, fixed orientation, lead-batteries storage, constant power demand). The second has the same purpose but the collectors are fully tracked. The results permit to compare both solutions. The model and computer program constitute a very flexible tool in designing photovoltaic generators.

Granular Bed Filter Development Program. Final report

Abstract: This is an intensive program to determine the scientific principle upon which granular-bed filtration operates and to design and construct a Granular-Bed Filter (GBF) device which can be subjected to controlled cold-flow testing for verification of these principles. The objective is to generate the desired information on the cold-flow model for future application, correlation, performance prediction, and implementation on a second generation GBF hot-flow model. The scope of the cold-flow program incorporates: (1) theoretical analysis, in which the theories and mechanisms of the interaction of exhaust gases and granular media are studied and reduced to mathematical expressions for computer simulation; (2) design and construction of the cold-flow model for parametric testing and correlation with the math model; (3) installation of a particle injection and sampling facility to enable controlled dust injection, particle sampling and analysis, and filter performance determination; and (4) evaluation of filter screen deposition phenomena and the effectiveness of various deposit-removing devices.

TDRSS Performance Evaluation for Shuttle Services Using Analytical Simulation

Abstract: An analytical simulation package called LinCsim has been developed by LinCom Corporation for analytical verification of bit error rate and tracking service performance for both S - and Ku -band Shuttle user service through the Tracking and Data Relay Satellite System (TDRSS). The purpose of this effort was to provide a tool to assess overall system performances as well as the sensitivity to key subsystem parameters and to ensure compatibility of TDRSS and Shuttle transponder performance specifications. The evaluation is based on an analytical simulation, i.e., a combination of simulation techniques and analytical performance evaluation. This allows the use of a more realistic signal format than is possible with a purely analytical approach and maintains the advantage of short computation time. The Shuttle forward and return link models and the main features of the simulation are described. Sample results of the computer runs are provided for current power budgets and system design parameters.

A method for predicting full scale buffet response with rigid wind tunnel model fluctuating pressure data. Volume 2: Power spectral densities for method assessment

Abstract: The predicted upper and lower bounds power spectra for all of the cases and response items given in Volume 1 are plotted. The flight test power spectra are shown on each prediction plot for the nominal value of angle of attack that most closely agrees with the flexible angle for the prediction. The flight test and prediction conditions are given in tabular form for all cases considered.

Prediction of antenna array performance from subarray measurements

Abstract: Computer runs were used to determine the effect of mechanical distortions on array pattern performance. Subarray gain data, along with feed network insertion loss, and insertion phase data were combined with the analysis of Ruze on random errors to predict gain of a full array.