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Ground Simulator Studies of the Effects of Valve Friction, Stick Friction, Flexibility, and Backwash on Power Control System Quality

Description: Report presents results of tests made on a power control system by means of a ground simulator to determine the effects of various combinations of valve friction and stick friction on the ability of the pilot to control the system. Various friction conditions were simulated with a rigid control system, a flexible system, and a rigid system having some backlash. For the tests, the period and damping of the simulated airplane were held constant.
Date: February 8, 1957
Creator: Brown, B. Porter
Partner: UNT Libraries Government Documents Department

A comparison of carrier approach speeds as determined from flight tests and from pilot-operated simulator studies

Description: Report presenting a simplified analog simulator that can be used to predict the minimum comfortable approach speeds that could be used in carrier landings for airplanes that are limited by their ability to control altitude. Predicted speeds from initial tests on several planes are compared with values from flight tests in order to indicate the validity of simulator results.
Date: June 19, 1957
Creator: White, Maurice D. & Drinkwater, Fred J., III
Partner: UNT Libraries Government Documents Department

An Airborne Simulator Investigation of the Accuracy of an Optical Track Command Missile Guidance System

Description: Memorandum presenting an airborne missile simulator used to represent visually the predicted flight behavior of the Navy XASM-N-7 Bullpup air-to-surface missile, which is guided along the line of sight to the target by bang-bang radio signals controlled by the pilot of the launch airplane. Quantitative response measurements showed that the simulator gave a good representation of the trajectory and control characteristics predicted for the Bullpup missile, and the simulation appeared plausible to the pilots.
Date: November 23, 1956
Creator: Douvillier, Joseph G., Jr.; Foster, John V. & Drinkwater, Fred J., III
Partner: UNT Libraries Government Documents Department

An Air-Borne Target Simulator for Use With Scope-Presentation Type Fire-Control Systems

Description: Report describing the design and flight evaluation of an air-borne target simulator using precomputed relative kinematics for use in tracking studies of fighter aircraft equipped with scope-presentation type fire-control systems. Testing occurred in an F86D airplane equipped with a Hughes E-4 fire-control system. Results regarding relative kinematic programming considerations and restrictions to system evaluation are provided.
Date: May 10, 1957
Creator: Foster, John V.; Fulcher, Elmer C. & Heinle, Donovan R.
Partner: UNT Libraries Government Documents Department

Simulator Investigation of Command Reaction Controls

Description: Memorandum presenting an investigation of reaction controls that command velocity and attitude that compares them to the controls that command acceleration. Proportional acceleration reaction controls were found to be satisfactory over a much wide range of control effectiveness than were the on-off acceleration controls. The velocity and attitude controls were found to be superior to either of the acceleration controls.
Date: July 17, 1958
Creator: Holleman, Euclid C. & Stillwell, Wendell H.
Partner: UNT Libraries Government Documents Department

iTOUGH2 Command Reference

Description: iTOUGH2 is a program for parameter estimation, sensitivity analysis, and uncertainty propagation analysis. It is based on the TOUGH2 simulator for non-isothermal multiphase flow in fractured and porous media. This report contains a detailed description of all iTOUGH2 commands.
Date: June 18, 2002
Creator: Finsterle, Stefan
Partner: UNT Libraries Government Documents Department

iTOUGH2 Sample Problems

Description: iTOUGH2 is a program for parameter estimation, sensitivity analysis, and uncertainty propagation analysis. It is based on the TOUGH2 simulator for non-isothermal multiphase flow in fractured and porous media. This report contains a collection of iTOUGH2 sample problems.
Date: June 18, 2002
Creator: Finsterle, Stefan
Partner: UNT Libraries Government Documents Department

The Use of Simulation for the Design and Analysis of Thermophotovoltaic Networks

Description: Simulation has provided valuable quantification of the fundamental behavior of thermophotovoltaic cell networks. The results of simulation studies have supported the design and fabrication of small-scale demonstration networks and are expected to guide assembly of large-scale systems. This paper describes the methodology and software simulator developed to address issues in thermophotovoltaic (TPV) networking, including failure analysis, electrical network design, and nonuniform illumination. Results from simulation studies are given illustrating their application to the design and fabrication of small-scale TPV arrays.
Date: July 20, 2004
Creator: Oppenlander, JE; Vell, JL; Gaes, WS; Siganporia, DM; Danielson, LR & Dashiell, MW
Partner: UNT Libraries Government Documents Department

Qualitative Simulator Study of Longitudinal Stick Forces and Displacements Desirable During Tracking

Description: In this study in which an airplane simulator with one degree of freedom (pitch) was used, results were determined for three conditions of airplane dynamics. For an undamped natural frequency of 1/2 cps with a damping ratio of 0.18 and for an undamped natural frequency of 1 cps with a damping ratio of 0.11, moderate longitudinal stick forces and displacements were desired.
Date: February 1958
Creator: Faber, Stanley
Partner: UNT Libraries Government Documents Department

The case of the missing supercomputer performance : achieving optimal performance on the 8, 192 processors of ASCI Q

Description: In this paper we describe how we improved the effective performance of ASCI Q, the world's second-fastest supercomputer, to meet our expectations. Using an arsenal of performance-analysis techniques including analytical models, custom microbenchmarks, full applications, and simulators, we succeeded in observing a serious-but previously undetectable-performance problem. We identified the source of the problem, eliminated the problem, and 'closed the loop' by demonstrating improved application performance. We present our methodology and provide insight into performance analysis that is immediately applicable to other large-scale cluster-based supercomputers.
Date: January 1, 2003
Creator: Petrini, F. (Fabrizio); Kerbyson, D. J. (Darren J.) & Pakin, S. D. (Scott D.)
Partner: UNT Libraries Government Documents Department

Spectral Measurements of Pulse Solar Simulators

Description: Spectral measurements of pulse solar simulators are used to quantify the wavelength-dependant characteristics of the light. Because every PV device has a unique spectral response, it is important to know the spectral irradiance and to periodically monitor the spectra for changes. Measurements are made at the National Renewable Energy Laboratory (NREL) using several different techniques including the NREL-developed Pulse Analysis Spectroradiometer System (PASS).
Date: November 12, 1998
Creator: Cannon, T. W.
Partner: UNT Libraries Government Documents Department

A New Generation Chemical Flooding Simulator

Description: The premise of this research is that a general-purpose reservoir simulator for several improved oil recovery processes can and should be developed so that high-resolution simulations of a variety of very large and difficult problems can be achieved using state-of-the-art computing and computers. Such a simulator is not currently available to the industry. The goal of this proposed research is to develop a new-generation chemical flooding simulator that is capable of efficiently and accurately simulating oil reservoirs with at least a million gridblocks in less than one day on massively parallel computers. Task 1 is the formulation and development of solution scheme, Task 2 is the implementation of the chemical module, and Task 3 is validation and application. We have made significant progress on all three tasks and we are on schedule on both technical and budget. In this report, we will detail our progress on Tasks 1 through 3 for the first six months of the project.
Date: March 1, 2002
Creator: Pope, Gary A.; Sepehrnoori, Kamy & Delshad, Mojdeh
Partner: UNT Libraries Government Documents Department

Reservoir Characterization of Upper Devonian Gordon Sandstone, Jacksonburg, Stringtown Oil Field, Northwestern West Virginia

Description: This report gives results of efforts to determine electrofacies from logs; measure permeability in outcrop to study very fine-scale trends; find the correlation between permeability measured by the minipermeameter and in core plugs, define porosity-permeability flow units; and run the BOAST III reservoir simulator using the flow units defined for the Gordon reservoir.
Date: May 21, 2002
Creator: Ameri, S.; Aminian, K.; Avary, K.L.; Bilgesu, H.I.; Hohn, M.E.; McDowell, R.R. et al.
Partner: UNT Libraries Government Documents Department

Solutions of test problems for disposal of CO2 in saline aquifers

Description: This report presents detailed results for three flow problems involving CO2 migration in saline aquifers, that had been posed as part of an international code intercomparison study. Selected data for PVT properties of aqueous mixtures involving CO2 are given, and the dynamics of immiscible displacement of an aqueous phase by supercritical CO2 is discussed. Simulations were conducted with a version of the TOUGH2 general purpose reservoir simulator that includes a special property package for supercritical CO2. The results can serve as benchmarks for debugging numerical simulation models.
Date: March 5, 2003
Creator: Pruess, Karsten & Garcia, Julio
Partner: UNT Libraries Government Documents Department

iTOUGH2: From parameter estimation to model structure identification

Description: iTOUGH2 provides inverse modeling capabilities for the TOUGH2 family of nonisothermal multiphase flow simulators. It can be used for a formalized sensitivity analysis, parameter estimation by automatic model calibration, and uncertainty propagation analyses. While iTOUGH2 has been successfully applied for the estimation of a variety of parameters based on different data types, it is recognized that errors in the conceptual model have a great impact on both the estimated parameters and the subsequent model predictions. Identification of the most suitable model structure is therefore one of the most important and most difficult tasks. Within the iTOUGH2 framework, model identification can be partly addressed through appropriate parameterization of alternative conceptual-model elements. In addition, statistical measures are provided that help rank the performance of different conceptual models. We present a number of features added to the code that allow for a better parameterization of conceptual model elements, specifically heterogeneity. We discuss how these new features can be used to support the identification of key model structure elements and their impact on model predictions.
Date: May 12, 2003
Creator: Finsterle, Stefan
Partner: UNT Libraries Government Documents Department

Development of an Improved Permeability Modification Simulator

Description: This report describes the development of an improved permeability modification simulator performed jointly by BDM Petroleum Technologies and Schlumberger Dowell under a cooperative research and development agreement (CRADA) with the US Department of Energy. The improved simulator was developed by modifying NIPER's PC-GEL permeability modification simulator to include a radial model, a thermal energy equation, a wellbore simulator, and a fully implicit time-stepping option. The temperature-dependent gelation kinetics of a delayed gel system (DGS) is also included in the simulator.
Date: March 9, 1999
Creator: Gao, H.W. & Elphnick, J.
Partner: UNT Libraries Government Documents Department

Productivity and Injectivity of Horizontal Wells

Description: The generation of suitable simulation grids for heterogeneous media and specific discretization issues that arise. Streamlines and equipotentials are used to define our base grids. Since streamlines are concentrated in high velocity regions they provide a natural means of clustering fine grid cells in crucial flow regions. For complex configurations and particularly for strongly heterogeneous regions the resulting grid cells can become very distorted due to extremely high curvatures. Two types of cell centered formulation are examined together with a cell vertex-point distributed scheme. Important distinctions are found for highly distorted cells. The new grids are tested for accuracy in terms of critical breakthrough parameters and it is shown that a much higher level of grid resolution is required by conventional simulators in order to achieve results that are comparable with those computed on relatively coarse streamline-potential grids.
Date: November 16, 1999
Creator: Aziz, Khalid; Hewett, Thomas A.; Arbabi, Sepehr & Smith, Marilyn
Partner: UNT Libraries Government Documents Department

A New Generation Chemical Flooding Simulator

Description: The premise of this research is that a general-purpose reservoir simulator for several improved oil recovery processes can and should be developed so that high-resolution simulations of a variety of very large and difficult problems can be achieved using state-of-the-art algorithms and computers. Such a simulator is not currently available to the industry. The goal of this proposed research is to develop a new-generation chemical flooding simulator that is capable of efficiently and accurately simulating oil reservoirs with at least a million gridblocks in less than one day on massively parallel computers. Task 1 is the formulation and development of solution scheme, Task 2 is the implementation of the chemical module, and Task 3 is validation and application. In this final report, we will detail our progress on Tasks 1 through 3 of the project.
Date: January 1, 2005
Creator: Pope, Gary A.; Sepehrnoori, Kamy & Delshad, Mojdeh
Partner: UNT Libraries Government Documents Department

TOP500 Supercomputers for November 2002

Description: 20th Edition of TOP500 List of World's Fastest Supercomputers Released MANNHEIM, Germany; KNOXVILLE, Tenn.;&BERKELEY, Calif. In what has become a much-anticipated event in the world of high-performance computing, the 20th edition of the TOP500 list of the world's fastest supercomputers was released today (November 15, 2002). The Earth Simulator supercomputer installed earlier this year at the Earth Simulator Center in Yokohama, Japan, is with its Linpack benchmark performance of 35.86 Tflop/s (trillions of calculations per second) retains the number one position. The No.2 and No.3 positions are held by two new, identical ASCI Q systems at Los Alamos National Laboratory (7.73Tflop/s each). These systems are built by Hewlett-Packard and based on the Alpha Server SC computer system.
Date: November 15, 2002
Creator: Strohmaier, Erich; Meuer, Hans W.; Dongarra, Jack & Simon, Horst D.
Partner: UNT Libraries Government Documents Department

A New Generation Chemical Flooding Simulator

Description: The premise of this research is that a general-purpose reservoir simulator for several improved oil recovery processes can and should be developed so that high-resolution simulations of a variety of very large and difficult problems can be achieved using state-of-the-art computing and computers. Such a simulator is not currently available to the industry. The goal of this proposed research is to develop a new-generation chemical flooding simulator that is capable of efficiently and accurately simulating oil reservoirs with at least a million gridblocks in less than one day on massively parallel computers. Task 1 is the formulation and development of solution scheme, Task 2 is the implementation of the chemical module, and Task 3 is validation and application.
Date: September 30, 2002
Creator: Pope, Gary A.; Sepehrnoori, Kamy & Delshad, Mojdeh
Partner: UNT Libraries Government Documents Department

Evaluation of leading scalar and vector architectures for scientific computations

Description: The growing gap between sustained and peak performance for scientific applications is a well-known problem in high performance computing. The recent development of parallel vector systems offers the potential to reduce this gap for many computational science codes and deliver a substantial increase in computing capabilities. This project examines the performance of the cacheless vector Earth Simulator (ES) and compares it to superscalar cache-based IBM Power3 system. Results demonstrate that the ES is significantly faster than the Power3 architecture, highlighting the tremendous potential advantage of the ES for numerical simulation. However, vectorization of a particle-in-cell application (GTC) greatly increased the memory footprint preventing loop-level parallelism and limiting scalability potential.
Date: April 20, 2004
Creator: Simon, Horst D.; Oliker, Leonid; Canning, Andrew; Carter, Jonathan; Ethier, Stephane & Shalf, John
Partner: UNT Libraries Government Documents Department

TOP500 Supercomputers for June 2003

Description: 21st Edition of TOP500 List of World's Fastest Supercomputers Released MANNHEIM, Germany; KNOXVILLE, Tenn.;&BERKELEY, Calif. In what has become a much-anticipated event in the world of high-performance computing, the 21st edition of the TOP500 list of the world's fastest supercomputers was released today (June 23, 2003). The Earth Simulator supercomputer built by NEC and installed last year at the Earth Simulator Center in Yokohama, Japan, with its Linpack benchmark performance of 35.86 Tflop/s (teraflops or trillions of calculations per second), retains the number one position. The number 2 position is held by the re-measured ASCI Q system at Los Alamos National Laboratory. With 13.88 Tflop/s, it is the second system ever to exceed the 10 Tflop/smark. ASCIQ was built by Hewlett-Packard and is based on the AlphaServerSC computer system.
Date: June 23, 2003
Creator: Strohmaier, Erich; Meuer, Hans W.; Dongarra, Jack & Simon, Horst D.
Partner: UNT Libraries Government Documents Department

Productivity and injectivity of horizontal wells. Quarterly report, April 1, 1995--June 30, 1995

Description: The following activities have been carried out in the last three months: Work on developing a three-dimensional Voronoi grid simulator is progressing. Extensive testing of the grid generation and visualization modules of the simulator is continuing while modifications and improvements are being made to these capabilities; The recently developed semi-analytical method for calculating critical cresting rates is being extended for the case of simultaneous gas and water coning toward a horizontal well; The accuracy of available correlations and analytical models for breakthrough times of horizontal wells is being investigated through simulations of a field case; Work on developing methods for coupling between reservoir and the werbore through a network modeling approach is progressing. The current stage of the study involves evaluation of available analytical methods; The necessary modifications have been made to the rig at the Marathon facility and the high rate two-phase flow experiments are about to commence; new correlations for wall friction and interfacial friction factors have been developed for the stratified flow in horizontal and inclined pipes. After further testing this new approach will be used in our mechanistic model; and this quarterly report has been entirely devoted to the task fisted in the last item above and we only present an abridged version of the Masters report of Mr. Liang-Biao Ouyang on which it is based. The complete study will be included in the next Annual Report of the Project.
Date: August 1, 1995
Creator: Aziz, K. & Hewett, T.A.
Partner: UNT Libraries Government Documents Department