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Air Force Institute of Technology

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Articles 5341 - 5370 of 5697

Full-Text Articles in Engineering

Design And Construction Of A Channel Electron Multiplier Based Mossbauer Spectroscopy System, Daniel J. Robbins Mar 1992

Design And Construction Of A Channel Electron Multiplier Based Mossbauer Spectroscopy System, Daniel J. Robbins

Theses and Dissertations

A channel electron multiplier (cem) detector system was designed and built to provide a signal to a Mossbauer spectroscopy system in an effort to obtain a better signal-to-noise ratio than achievable with a proportional counter system. Three cems are contained in a vacuum chamber built using standard components. Gamma, rays of 14.4-keV energy from a 57Co source enter from outside the chamber through a window and are absorbed by an 57Fe target near the cems. The target emits internal conversion electrons which are collected by the cems and a Mossbauer spectrometer collects the signal. The system produces a …

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Design Of A Warm X-Ray Radiation Environment For Nuclear Weapons Effects Testing In The Nova-Upgrade Facility, Jeffrey E. Malapit Mar 1992

Design Of A Warm X-Ray Radiation Environment For Nuclear Weapons Effects Testing In The Nova-Upgrade Facility, Jeffrey E. Malapit

Theses and Dissertations

This engineering design project examined the creation of a radiation environment for warm x-ray effects testing in the Nova Upgrade laser facility. With the use of the MORSE Monte Carlo Code and the DABL69 Broad-group cross section library, the ignition of an inertial confinement fusion pellet using D-T fuel in a test cassette was modeled in the Nova Upgrade's target chamber. Various x-ray scattering materials were used in the test cassette to include enriched lithium hydride, polyethylene, liquid hydrogen, liquid helium, and liquid methane. The lithium hydride produced the best warm x-ray doses and least neutron dose. The predicted x-ray …

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Multilayer Perceptrons For Classification, Lisa M. Belue Mar 1992

Multilayer Perceptrons For Classification, Lisa M. Belue

Theses and Dissertations

Techniques for training, testing, and validating multilayer perceptrons are thoroughly examined. Results obtained using perceptrons are compared and contrasted with two multivariate discriminant analysis techniques- logistic regression and k neighbor. Methods for determining significant input features are investigated and a procedure for examining the confidence to place in the significance of these features is developed. Procedures to evaluate the applicability of high-order feature inputs are examined. These methods and procedures are applied to two very different applications. The first application concerns the prediction of Air Force pilot retention/separation rates for input to force projection models. The second application concerns the …

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An Analysis Of The Endurance Of Mobile Satellite Command And Control Systems, Steven O. Brown Mar 1992

An Analysis Of The Endurance Of Mobile Satellite Command And Control Systems, Steven O. Brown

Theses and Dissertations

This study investigated the endurance of a single deployed generic mobile space (GMS) command and control (C2) system. Specifically, factors which affect overall system performance were examined. The analysis began with the development of a simulation model for a GMS C2 system. Optimal settings of factor levels were determined by using the model to find peak system endurance and availability. Factors set were field support vehicle (FSV) access, numbers of maintenance personnel, and numbers of spare components available. After optimum values were chosen for these factors, an experimental design was conducted to determine factor effect between maintenance manpower and the …

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Transformation Of Combat Data In Support Of Battle Trace, Hyoung-Kyu Choi Mar 1992

Transformation Of Combat Data In Support Of Battle Trace, Hyoung-Kyu Choi

Theses and Dissertations

The purpose of this study was to find an appropriate way of characterizing battle data as a function of time. This study was initially designed to remove the numerical instability problem cited in Barr's battle trace methodology as suggested by TRAC-MTRY. The research focused on the instability problem and identifying/recommending a technique that improved the efficiency of computation, and enhanced an analyst's ability to meaningfully interpret the battle trace. Two Lanchester's Square Law based methodologies are introduced and analyzed. The results of this analysis indicate that the battle trace of a constant value generated by Lanchester's Square Law integration seemed …

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Feasibility Of An Antiproton Catalyzed Fission Fragment Rocket, David S. Hidinger Mar 1992

Feasibility Of An Antiproton Catalyzed Fission Fragment Rocket, David S. Hidinger

Theses and Dissertations

The purpose of this project was to investigate the feasibility of an antiproton catalyzed fission fragment rocket (FFR). The FFR is characterized by the extraction of fission fragments from the fuel, and the utilization of their kinetic energy for thrust generation. A significant drawback to previous FFR designs was the required critical nuclear pile as the fission fragment source. The author examined the possibility of replacing the critical pile with a sub- critical pile driven by antiprotons. Recent experiments have revealed that antiprotons stimulate highly energetic fissions in 238U, with a neutron multiplicity of 13.7 neutrons per fissions. This interaction …

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Visual Information Processing And Response Time In Traffic-Signal Cognition, Hasan H. Demirarslan Mar 1992

Visual Information Processing And Response Time In Traffic-Signal Cognition, Hasan H. Demirarslan

Theses and Dissertations

In man-machine design, it is important to quantify the reaction time components instead of simply determining the lump-sum reaction time to stimulus. The primary purpose of this thesis was to investigate the reaction time components, such as visual perception and muscle response time, and to quantify them by separating from their aggregated sum. The prime example, traffic-signal cognition simulation was used to examine human reaction time to signal change. With a modified computer program that stimulates the driver's approach to the intersection, we measured the subject's reaction times and examined behavioral patterns. Twelve subjects were involved in the experiment. A …

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An Investigation Of Modifications To The Tac Campaign Model, Efgan Denguer Mar 1992

An Investigation Of Modifications To The Tac Campaign Model, Efgan Denguer

Theses and Dissertations

This research investigates the cost and budget modifications to Mixmaster which is an aggregate version of the Theater Attack Model (TAM). Seven simple cost employment methods, a goal programming approach, a probabilistic approach for determining cost coefficients, and goal programming version of that probabilistic approach were applied to Mixmaster. Also, Mixmaster was enhanced with an additional leading constraint to incorporate the Air Force tactical considerations in a campaign scenario. The results favor the advantages of the goal programming approaches. In addition, the probabilistic approach introducing the time factor in the computations promises more accurate results, given that the required parameters …

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Automating The Weekly Flight Scheduling Process At The Usaf Test Pilot School, Gary G. Foster Mar 1992

Automating The Weekly Flight Scheduling Process At The Usaf Test Pilot School, Gary G. Foster

Theses and Dissertations

This study investigated different scheduling solution approaches that could be automated and applied at the USAF Test Pilot School (TPS). Currently at the TPS, flight schedules are manually developed on a daily basis. Weekly flight schedules are not developed due to the large quantity of data that must be processed to develop a flight schedule for an entire week. A weekly flight scheduling approach would reduce the occurrence of scheduling problems and unbalanced resource utilization, both of which are often the result of a daily flight scheduling approach. In addition, posting a flight schedule for the entire week would improve …

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Optimization Of Stochastic Response Surfaces Subject To Constraints With Linear Programming, Robert G. Harvey Mar 1992

Optimization Of Stochastic Response Surfaces Subject To Constraints With Linear Programming, Robert G. Harvey

Theses and Dissertations

This research investigated an alternative to the traditional approaches of optimizing a stochastic response surface subject to constraints. This research investigated the bias in the expected value of the solution, possible alternative decision variable settings, and a method to improve the solution. A three step process is presented to evaluate stochastic response surfaces subject to constraints. Step 1 is to use a traditional approach to estimate the response surface and a covariance matrix through regression. Step 2 samples the objective function of the linear program (i.e., response surface) and identifies the extreme points visited. Step 3 presents a method to …

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Modular Simulation Of Hei Fragments And Blast Pressure, Gordon L. Galloway Mar 1992

Modular Simulation Of Hei Fragments And Blast Pressure, Gordon L. Galloway

Theses and Dissertations

The fragmentation and blast pressure of High Explosive Incendiary projectiles are major causes of aircraft fuel fires. Because Halon 1301 is being banned from DoD use as a fire suppressant, alternative fire suppressants must be developed and tested. These new suppressants must counteract the fire directly or eliminate one or more of the factors which cause the fire. To this end, this thesis takes a detailed look at the HEI processes that lead to a fire. A comprehensive review of the current knowledge and understanding of these processes is presented. In addition, hypothesized dependencies between the various processes are stated. …

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An A Priori Multiobjective Optimization Model Of A Search And Rescue Network, Joseph C. Imsand Jr. Mar 1992

An A Priori Multiobjective Optimization Model Of A Search And Rescue Network, Joseph C. Imsand Jr.

Theses and Dissertations

The purpose of this study was to determine the most robust frequency assignment for a search and rescue network. The focus was to assign weights to the transmitter areas of the network to determine which weight sequence produced the most robust frequency assignment. The DoD furnished weight sequences for twelve two-hour time blocks. These weight sequences were compared to a weight sequence with all weights having equal value. Network and linear programming were used to-solve this problem and generate frequency assignments for all weight sequences. Classical and tolerance sensitivity analysis were used to analyze the frequency assignments generated by the …

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Confidence Interval Estimation For Output Of Discrete-Event Simulations Using The Kalman Filter, Randall B. Howard Mar 1992

Confidence Interval Estimation For Output Of Discrete-Event Simulations Using The Kalman Filter, Randall B. Howard

Theses and Dissertations

Discrete-event simulation is computer modeling of stochastic, dynamic systems. The Kalman filter is a Bayesian stochastic estimation algorithm. Because of the correlated nature of simulation output, it is difficult to apply the methods of classical statistics directly when constructing confidence intervals of discrete-event simulation parameters. Through the determination of a dynamics equation and application of the Kalman filter to simulation output data, three new confidence interval construction techniques have been developed. One technique obtains an estimate of the mean value and its associated variance from an estimated Kalman filter. The second technique utilizes Multiple Model Adaptive Estimation (MMAE) techniques to …

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Developing Cmmca Flight Profiles For Cruise Missile Tracking, Andrew C. Hachman Mar 1992

Developing Cmmca Flight Profiles For Cruise Missile Tracking, Andrew C. Hachman

Theses and Dissertations

The Air Force has recently acquired two aircraft dedicated for cruise missile tracking. These aircraft, known as the Cruise Missile Mission Control Aircraft (CMMCA), are responsible for collecting data from the missile and United States. Due to tracking and positively controlling the missile during live fire testing over the western the limited tracking radar range and the flight characteristics of the CMMCA, tracking cruise missiles through complex maneuvers is not always possible. A FORTRAN optimization, based on flight simulation and optimal control theory, was written in a prior thesis effort in order to determine optimal CMMCA flight profiles for tracking …

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Hardware-Verification Through Logic Extraction, Michael A. Dukes Mar 1992

Hardware-Verification Through Logic Extraction, Michael A. Dukes

Theses and Dissertations

A Prolog-based system is described which employs logic-extraction to perform hardware-verification. The extraction rules are built automatically from hierarchical structural VHDL models, enabling the equivalence of a structural VHDL description and a layout specification to be verified. Pin-to-pin critical- path analysis is performed within the logic-extraction process; many noncritical paths are pruned early, making pin-to-pin critical path analysis of large circuits feasible. It is demonstrated that a design methodology based on logic extraction, VHDL, and a layout tool can provide a fabricated functionally- correct IC design without circuit-level or switch-level simulation. This methodology is shown to be practical for VLSI …

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Experimental Feedback Of Fractional Order States Of A Lightly Damped Structure, Robert C. Mccall Mar 1992

Experimental Feedback Of Fractional Order States Of A Lightly Damped Structure, Robert C. Mccall

Theses and Dissertations

The purpose of this study was to investigate the effectiveness of using fractional order time derivatives of position feedback signals in the active control of vibration. To that end, circuitry was built and evaluated that finds the half order derivative of an input signal. The magnitude responses of the fractional derivative circuits is very good, but there are large phase shifts present that may degrade the performance of the controllers. Two methods of incorporating the fractional derivative signals into the controller were examined. One method involved developing a similarity transformation that transforms an integer order state controller into an equivalent …

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Design And Analysis Of Electrical Circuits That Produce Fractional-Order Differentiation, Richard N. Hughes Mar 1992

Design And Analysis Of Electrical Circuits That Produce Fractional-Order Differentiation, Richard N. Hughes

Theses and Dissertations

Two half-order differentiator circuit designs were investigated and their electrical performance evaluated (Oldham and Oldfield). Initially, each circuit design was computer modelled and simulated using the HSPICE computer analysis program. Then, each circuit design (Oldham and Oldfield) was fabricated with two different component technologies. This resulted in four circuits, realized on printed circuit boards, to be evaluated--Oldham discrete component; Oldham hybrid component; Oldfield discrete component; and Oldfield surface mount component. The characterizations of each circuit's electrical performance is documented with time, phase, gain, noise and spectrum responses. A comparison of each circuit's performance versus the design criteria and computer model …

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Gamma-Ray Effects Testing In Lawrence Livermore National Laboratory's Nova Upgrade Facility, David H. Marchant Mar 1992

Gamma-Ray Effects Testing In Lawrence Livermore National Laboratory's Nova Upgrade Facility, David H. Marchant

Theses and Dissertations

Gamma ray effects testing in Lawrence Livermore National Laboratory's (LLNL) planned Nova Upgrade facility is examined. Emphasis is placed on converting neutron energy from inertial confinement fusion in to gamma rays while shielding the test objects from neutrons and debris. Although predicted gamma doses in the Nova Upgrade facility are an order of magnitude less than those produced in some current facilities, dose uniformity, the ratio of minimum to maximum gamma dose is predicted to be greater than 0.75 across a larger, 13, 000 cm2, test bed. Peak gamma dose rates are predicted to be on the order …

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Exponential Characteristic Spatial Quadrature For Discrete Ordinates Neutral Particle Transport In Slab Geometry, Glenn E. Sjoden Mar 1992

Exponential Characteristic Spatial Quadrature For Discrete Ordinates Neutral Particle Transport In Slab Geometry, Glenn E. Sjoden

Theses and Dissertations

A new discrete ordinates spatial quadrature scheme is presented for solving neutral particle transport problems. This new scheme, called the exponential characteristic method, is developed here in slab geometry with isotropic scattering. This method uses a characteristic integration of the Boltzmann transport equation with an exponential function as the assumed from of the source distribution, continuous across each spatial cell. The exponential source function is constructed to globally conserve zeroth and first spatial source moments and is non-negative. Characteristic integration ensures non- negative fluxes and flux moments. Numerical testing indicates that convergence of the exponential characteristic scheme is fourth order …

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An Outline For A Manufacturing Planning And Control System For A Repair/ Overhaul/Rebuilding Environment, Peter H. Miyares Mar 1992

An Outline For A Manufacturing Planning And Control System For A Repair/ Overhaul/Rebuilding Environment, Peter H. Miyares

Theses and Dissertations

This study outlines a structure for a manufacturing planning and control (MPC) system for a repair/overhaul/rebuilding environment. Included an examination of the organizational components that must be incorporated into the system and the planning functions for which the system can be used. The study compares and contrasts the differences between an MPC system for a maintenance organization and a manufacturing organization and concludes that the MPC system for a maintenance organization must account for the greater degree of variability that occurs within the process. The proposed system is composed of an information system which collects data from throughout an organization …

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Causal Univariate Spatial-Temporal Autoregressive Moving Averages (Starma) Modelling Of Target Information To Generate Tasking Of A World-Wide Sensor System, Kelly A. Greene Mar 1992

Causal Univariate Spatial-Temporal Autoregressive Moving Averages (Starma) Modelling Of Target Information To Generate Tasking Of A World-Wide Sensor System, Kelly A. Greene

Theses and Dissertations

The Department of Defense employs a resource limited world-wide sensor system to detect certain events of interest. The purpose of this research was to establish a methodology using a univariate causal STARMA model for forecasting the relative probability of an event occurring in a geographical location during a time block of the day. These relative probabilities are used as input for a tasking model that assigns the scarce sensor resources so as to optimize the detection of these events. The STARMA model is appropriate for forecasting the relative probabilities because a definite temporal relationship and a definite spatial relationship exists …

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Spartan: An Instructional High Resolution Land Combat Model, David K. Cox Mar 1992

Spartan: An Instructional High Resolution Land Combat Model, David K. Cox

Theses and Dissertations

This project developed an instructional high resolution land combat simulation model. The purpose of this model is to demonstrate common techniques of modeling used in the present generation of US Army land combat models. This model is stochastic and uses an event scheduling type of discrete event time algorithm. The model represents a maximum of two six-man infantry squads in direct fire combat. The individual soldiers move, search for targets, engage targets, and react to hostile encounters. The data values provided will the model are all. generic and hypothetical. The model is only intended as a demonstration tool and has …

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Saber: Airland Combat Training Model Credibility Assessment And Methodology, David L. Scagliola Mar 1992

Saber: Airland Combat Training Model Credibility Assessment And Methodology, David L. Scagliola

Theses and Dissertations

Saber is a theater-level, airland combat training model, designed by a number of computer science and engineering students and faculty at the Air Force Institute of Technology (AFIT). Saber is intended to replace the Agile model, which is currently used at the Air Force Wargaming Center, Maxwell AFB, Alabama for Theater Warfare Exercise (TWX) training purposes. This thesis focuses on the progress made towards generating the Saber training model, its ability to meet the objectives specified by the Wargaming Center, and its ability to represent actual combat. Specifically, this thesis is directed towards characterizing, establishing a credibility assessment, and developing …

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Gettysburg: An Analysis Of The Training Value Of Commercial Models, Jude C. Fernan Mar 1992

Gettysburg: An Analysis Of The Training Value Of Commercial Models, Jude C. Fernan

Theses and Dissertations

This study investigated the possibilities of using commercial combat models/war games dealing with the battle of Gettysburg as aids for the training of soldiers and leaders in the military. With the downsizing of the military and the high cost of training, there exists a need to reduce training costs while not affecting the quality of training. The military employs various military models to assist in training but has yet to fully tap the wealth of commercial combat models. One reason may be the lack of an investigative analysis into the soundness and applicability of commercial combat models to military training. …

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Boolean Reasoning And Informed Search In The Minimization Of Logic Circuits, James J. Kainec Mar 1992

Boolean Reasoning And Informed Search In The Minimization Of Logic Circuits, James J. Kainec

Theses and Dissertations

The minimization of logic circuits has been an important area of research for more than a half century. The approaches taken in this field, however, have for the most part been ad hoc. Boolean techniques have been employed to manipulate formulas, but not to perform symbolic reasoning. Boolean equations are employed principally as icons; they are never solved. The first objective of this dissertation is to apply Boolean reasoning systematically and uniformly to the minimization problem. Boolean reasoning entails the reduction of systems of Boolean equations to a single equation; the single equation is an abstraction, independent of the form …

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An Examination Of Wing Rock For The F-15, Michael T. Davison Feb 1992

An Examination Of Wing Rock For The F-15, Michael T. Davison

Theses and Dissertations

Wing rock in the F-15 was examined both analytically and experimentally. Using a previously developed model for the F-15, bifurcation analysis and continuation techniques were used to map out the periodic wing rock solutions and the equilibrium solutions leading up to wing rock. this was done for four maneuvers; a 1 g stall, rudder sweeps, constant bank turns and a symmetric pullup. To supplement this research, time history simulations were used to examine. the time history of wing rock. A study of stability derivatives was also done, to determine the critical parameters in wing rock. Bifurcation was also used to …

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A Computer Based Educational Aid For The Instruction Of Combat Modeling, Richard S. Moore Feb 1992

A Computer Based Educational Aid For The Instruction Of Combat Modeling, Richard S. Moore

Theses and Dissertations

The Air Force Institute of Technology is one of few institutions that teaches combat modeling. Combat models are typically dynamic computer simulations of specialized dynamic processes. Great difficulty exists in portraying these dynamic and recurrent processes with conventional static diagrams. This thesis produced a computer-based instructional aid which presents animated examples of processes common to combat models, demonstrates a simple few-on-few aerial combat model, and encourages student exploration and interaction with these presentations. This aid provides dynamic examples of random number generation, detection processes, target selection, and target destruction. A complete combat model demonstrating a few-on-few air duel is animated …

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Method For Gaseous Component Indentification With #3 Polymeric Film, Edward S. Kolesar Jr. Dec 1991

Method For Gaseous Component Indentification With #3 Polymeric Film, Edward S. Kolesar Jr.

AFIT Patents

A sensor having an interdigitated gate electrode field effect transistor (IGEFET) coupled to an electron beam evaporated copper phthalocyanine thin film is used to selectively detect parts-per-billion concentration levels of atmosphere contaminants such as nitrogen dioxide (NO2) and diisopropyl methylphosphonate (DIMP). The sensor is excited with a voltage pulse, and its time- and frequency-domain response are examined. The envelopes of the magnitude of the normalized difference frequency spectrums reveal features which unambiguously distinguish the NO2 and DIMP exposures.

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Migrating A C-Based Cad Tool To An Object-Oriented Database/C++ Environment: Conversion Costs And Performance Analysis, Mark A. Roth, Timothy M. Jacobs Dec 1991

Migrating A C-Based Cad Tool To An Object-Oriented Database/C++ Environment: Conversion Costs And Performance Analysis, Mark A. Roth, Timothy M. Jacobs

AFIT Documents

his paper examines the potential of object-oriented databases to support complex design applications. To do this we migrated the Magic very large scale integrated (VLSI) circuit design tool written in the C language to a new environment in which Magic's existing file management code is replaced with a C++ language interface to the commercial object-oriented database management system (OODBMS) product Object Store. In our initial implementation we found the performance of this tool as implemented on the OODBMS to be marginally faster than the tool as currently implemented with a flat file system in several critical areas. Increased functionality, including …

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High-Resolution Tvd Schemes For The Analysis Of 1. Inviscid Supersonic And Transonic Flows. 2. Viscous Flows With Shock-Induced Separation And Heat Transfer, Mark A. Driver Dec 1991

High-Resolution Tvd Schemes For The Analysis Of 1. Inviscid Supersonic And Transonic Flows. 2. Viscous Flows With Shock-Induced Separation And Heat Transfer, Mark A. Driver

Theses and Dissertations

Application of TVD schemes to both inviscid and viscous flows is considered. The mathematical and physical bases of TVD schemes are discussed. First and second-order accurate TVD schemes and a second-order accurate Lax- Wendroff scheme are used to compute solutions to the Riemann problem in order to investigate the capability of each to resolve shocks, rarefactions, and contact surfaces. Second-order finite-volume and finite-difference TVD schemes are used to obtain solutions to inviscid supersonic and transonic cascade flow problems. TVD schemes are shown to be superior to the Lax-Wendroff family of schemes for both transient and steady-state computations. TVD methodology is …

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