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Air Force Institute of Technology

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Full-Text Articles in Engineering

Alternate Materials For High-Speed Projectile Casing, Andrew W. Beard Mar 2020

Alternate Materials For High-Speed Projectile Casing, Andrew W. Beard

Theses and Dissertations

A high-speed projectile impact is a highly complex dynamic problem that can be simplified with the use of finite element analysis solvers. Abaqus/Explicit was used to evaluate the impact of various projectiles using a plane strain setup. Using a baseline stainless steel projectile, the proposed sandwich construction design was analyzed and compared to the baseline projectile. The overall goal was to see if a new composite casing could perform similarly to the simple baseline projectile. The sandwich construction used stainless steel, tungsten, and silicon-carbide reinforce aluminum as outer and inner shell materials. The core material was created using additive manufacturing …

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Investigation Of Ultem 9085 For Use In Printed Orbital Structures, William R. Gallagher Mar 2020

Investigation Of Ultem 9085 For Use In Printed Orbital Structures, William R. Gallagher

Theses and Dissertations

Additive manufacturing is revolutionizing industries ranging from medicine to space. However, the structural characteristics of plastic parts created by these methods are not as well understood as their more established counterparts. This research explored two relevant areas: how the structural characteristics of ULTEM 9085 plastic behaved after exposure to orbital conditions and the design of the cross-sectional area of a beam to be 3-D printed in microgravity based on the expected loads from the printer. To study orbital effects, ULTEM 9085 was printed into 1/4th scale ASTM D638- 14 dogbones using a Stratasys 450mc printer. These dogbones were placed in …

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Timely Near-Optimal Path Generation For An Unmanned Aerial System In A Highly Constrained Environment, Kyle J. Matissek Mar 2020

Timely Near-Optimal Path Generation For An Unmanned Aerial System In A Highly Constrained Environment, Kyle J. Matissek

Theses and Dissertations

A current challenge in path planning is the ability to efficiently calculate a near-optimum path solution through a highly-constrained environment in near-real time. In addition, computing performance on a small unmanned aerial vehicle is typically limited due to size and weight restrictions. The proposed method determines a solution quickly by first mapping a highly constrained three-dimensional environment to a two-dimensional weighted node surface in which the weighting accounts for both the terrain gradient and the vehicle's performance. The 2D surface is then discretized into triangles which are sized based upon the vehicle maneuverability and terrain gradient. The shortest feasible path …

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Signal Quality Monitoring Of Gnss Signals Using A Chip Shape Deformation Metric, Nicholas C. Echeverry Mar 2020

Signal Quality Monitoring Of Gnss Signals Using A Chip Shape Deformation Metric, Nicholas C. Echeverry

Theses and Dissertations

The Global Navigation Satellite System continues to become deeply em-bedded within modern civilization, and is depended on for confident, accurate navigation information. High precision position and timing accuracy is typically achieved using differential processing, however these systems provide limited compensation for distortions caused by multi-path or faulty satellite hardware. Signal Quality Monitoring (SQM) aims to provide confidence in a receivers Position, Navigation, and Timing solution and to offer timely warnings in the event that signal conditions degrade to unsafe levels. The methods presented in this document focus on implementing effective SQM using low-cost Commercial Off-the-Shelf equipment, a Software Defined Radio, …

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Mismatched Filter Effects On Synthetic Aperture Radar Image Quality Metrics, Jerrod M. Kempf Mar 2020

Mismatched Filter Effects On Synthetic Aperture Radar Image Quality Metrics, Jerrod M. Kempf

Theses and Dissertations

Detection of targets across a wide dynamic range is an enduring challenge in radar. This work formulates a modified least-squares mismatched filter that greatly reduces these sidelobes in order to enable the detection of small radar cross section targets in the presence of considerably larger scatterers, increasing the dynamic range. Unlike previous mismatched filters, the proposed filter is applicable to noisy, oversampled signals with no requirements on signal structure. Range profiles and images are presented to demonstrate the superior sidelobe suppression of the modified least-squares mismatched filter in comparison to the commonly employed matched filter. Various weighting vectors are introduced …

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Comparison Of Visual Simultaneous Localization And Mapping Methods For Fixed-Wing Aircraft Using Slambench2, Patrick R. Latcham Mar 2020

Comparison Of Visual Simultaneous Localization And Mapping Methods For Fixed-Wing Aircraft Using Slambench2, Patrick R. Latcham

Theses and Dissertations

Visual Simultaneous Localization and Mapping (VSLAM) algorithms have evolved rapidly in the last few years, however there has been little research evaluating current algorithm's effectiveness and limitations when applied to tracking the position of a fixed-wing aerial vehicle. This research looks to evaluate current monocular VSLAM algorithms' performance on aerial vehicle datasets using the SLAMBench2 benchmarking suite. The algorithms tested are MonoSLAM, PTAM, OKVIS, LSDSLAM, ORB-SLAM2, and SVO, all of which are built into the SLAMBench2 software. The algorithms' performance is evaluated using simulated datasets generated in the AftrBurner Engine. The datasets were designed to test the quality of each …

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A Study Of Execution Performance For Rust-Based Object Vs Data Oriented Architectures, Joseph A. Vagedes Mar 2020

A Study Of Execution Performance For Rust-Based Object Vs Data Oriented Architectures, Joseph A. Vagedes

Theses and Dissertations

To investigate the Data-Oriented Design (DOD) paradigm, in particular, an architecture built off its principles: the Entity-Component-System (ECS). ECS is commonly used by video game engines due to its ability to store data in a way that is optimal for the cache to access. Additionally, the structure of this paradigm produces a code-base that is simple to parallelize as the workload can be distributed across a thread-pool based on the data used with little to no need for data safety measures such as mutexes and locks. A final benefit, although not easily measured, is that the DOD paradigm produces a …

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Database Analysis To Improve U.S. Transportation Command Forecasting Processes, Maxwell C. Thompson Mar 2020

Database Analysis To Improve U.S. Transportation Command Forecasting Processes, Maxwell C. Thompson

Theses and Dissertations

The United States Transportation Command (USTRANSCOM) facilitates air, land, and sea transportation for the DOD. On a periodic basis, a myriad of different agencies within USTRANSCOM project future workload to facilitate resource planning, budgeting, and reimbursable rate identification. Within USTRANSCOM, there are a variety of databases and metrics utilized for workload forecasts; neither a standard nor a preferred technique is prescribed. Currently, USTRANSCOM faces challenges in producing accurate workload forecasts [1]. These challenges can lead to unreliable budget requests and, ultimately, hinder the effectiveness and efficiency of USTRANSCOM [1]. For the purpose of routine aircraft movements of cargo and personnel, …

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Using A Field Mill Climatology To Assess All Lightning Launch Commit Criteria, Shane C. Gardner Mar 2020

Using A Field Mill Climatology To Assess All Lightning Launch Commit Criteria, Shane C. Gardner

Theses and Dissertations

Due to the danger and cost of lightning striking a space vehicle, the Cape Canaveral Air Force Station (CCAFS) balances between the mission of launching and cessation thereof to minimize the risk of a lightning strike. This process is mediated through a set of rules called the Lightning Launch Commit Criteria (LLCC). To date, no empirical modeling of these rules has been established. To alleviate this shortcoming, this thesis uses the voltage readings of the surrounding CCAFS surface field mills to establish the viability of modeling the entirety of the LLCC rules statistically. Converting approximately 312,000,000 field mill voltage readings …

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Object Detection With Deep Learning To Accelerate Pose Estimation For Automated Aerial Refueling, Andrew T. Lee Mar 2020

Object Detection With Deep Learning To Accelerate Pose Estimation For Automated Aerial Refueling, Andrew T. Lee

Theses and Dissertations

Remotely piloted aircraft (RPAs) cannot currently refuel during flight because the latency between the pilot and the aircraft is too great to safely perform aerial refueling maneuvers. However, an AAR system removes this limitation by allowing the tanker to directly control the RP A. The tanker quickly finding the relative position and orientation (pose) of the approaching aircraft is the first step to create an AAR system. Previous work at AFIT demonstrates that stereo camera systems provide robust pose estimation capability. This thesis first extends that work by examining the effects of the cameras' resolution on the quality of pose …

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Multi-Channel Security Through Data Fragmentation, Micah J. Hayden Mar 2020

Multi-Channel Security Through Data Fragmentation, Micah J. Hayden

Theses and Dissertations

This thesis presents a novel security system developed for a multi-channel communication architecture, which achieves security by distributing the message and its associated message authentication code across the available channels at the bit level, to support systems that require protection from confidentiality and integrity attacks without relying solely on traditional encryption. One contribution of the work is to establish some helpful terminology, present a basic theory for multi-channel communications, describe the services provided by an optimal system, and then implement a proof of concept system to demonstrate the concept's validity. This proof of concept, focused on the splitting and recombination …

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Characterization Of Reactive Ion Etch Chemistries Using Direct Write Lithography, Dylan T. Martin-Abood Mar 2020

Characterization Of Reactive Ion Etch Chemistries Using Direct Write Lithography, Dylan T. Martin-Abood

Theses and Dissertations

The DoD requires a variety of COTS and number of custom microelectronics to provide important functionality to critical military systems. Photolithography and DRIE are two techniques commonly used in the development of deep anisotropic features for the fabrication and modification of microelectronics and MEMS. However, standard photolithography techniques are ineffective for unique substrate geometries and DRIE processes require a chemical passivation step only applicable to Si substrates. This work confirmed the capability of RIE using DWL to perform deep, highly selective, anisotropic etching on elevated, non-circular substrates.

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Wideband Metasurface Antenna, Thomas A. Lepley Mar 2020

Wideband Metasurface Antenna, Thomas A. Lepley

Theses and Dissertations

This effort explored design of metasurface antennas and evaluated their suitability for ultra-wideband applications (2 to 18 GHz). Six unit cell types were characterized. Eigenmode simulations produced frequency vs. phase data for the unit cells, from which impedance vs. gap size data was computed. A holographic design equation was used to generate the metasurface antenna designs. The unit cell simulations revealed that the assumption of single mode operation is a constraint for wideband designs. An 8" by 8" metasurface antenna with a Rogers 3010 dielectric and a design frequency of 10 GHz was fabricated and tested. It had a 1.5:1 …

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Near Real-Time Zigbee Device Discrimination Using Cb-Dna Features, Yousuke Z. Matsui Mar 2020

Near Real-Time Zigbee Device Discrimination Using Cb-Dna Features, Yousuke Z. Matsui

Theses and Dissertations

Currently, Low-Rate Wireless Personal Area Networks (LR-WPAN) based on the Institute of Electrical and Electronics Engineers (IEEE) 802.15.4 standard are at risk due to open-source tools which allow bad actors to exploit unauthorized network access through various cyberattacks by falsifying bit-level credentials. This research investigates implementing a Radio Frequency (RF) air monitor to perform Near RealTime (NRT) discrimination of Zigbee devices using the IEEE 802.15.4 standard. The air monitor employed a Multiple Discriminant Analysis/Euclidean Distance classifier to discriminate Zigbee devices based upon Constellation-Based Distinct Native Attribute (CB-DNA) fingerprints. Through the use of CB-DNA fingerprints, Physical Layer (PHY) characteristics unique to …

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Focused Beam System Biaxial Material Characterization, Nicholas A. O'Gorman Mar 2020

Focused Beam System Biaxial Material Characterization, Nicholas A. O'Gorman

Theses and Dissertations

Electromagnetic material characterization is the process of determining the constitutive parameters (complex permittivity and permeability) of given a sample. Due to the large number of unknowns involved, multiple unique measurements are required for material property extraction. Many measurement methods, such as waveguides and striplines, possess a rigid internal structure that the sample being measured must adhere to. This rigidity limits these methods to samples that fit within the device and inhibits oblique sample orientations, limiting the number of independent measurements that can be obtained. A focus beam system, due to being an open system with greater freedom in sample size …

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Mc80: Quantifying Effect Of Fleet Health On Sortie Execution In F-16 Fleet, Kyle R. Gladney Mar 2020

Mc80: Quantifying Effect Of Fleet Health On Sortie Execution In F-16 Fleet, Kyle R. Gladney

Theses and Dissertations

By order of the Secretary of Defense, all of the US Air Force's F-16 units were tasked to improve their fleet health to a Mission Capability (MC) rate of 80 percent, as part of a Department of Defense-wide push to make its Critical Aviation Platforms, and the units that employ them, more ready and lethal. This study uses historical fleet health and sortie execution data captured from LIMS-EV (Weapon System Viewer, 2020) to create a multiple regression model that quantifies the value of increased fleet health, defined as either MC rate or Aircraft Availability (AA) rate, in terms of increasing …

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Resilient Aircraft Sustainment: Quantifying Resilience Through Asset And Capacity Allocation, Zachary B. Shannon Mar 2020

Resilient Aircraft Sustainment: Quantifying Resilience Through Asset And Capacity Allocation, Zachary B. Shannon

Theses and Dissertations

Decision makers lack a clear, generalizable method to quantify how additional investment in inventory and capacity equates to additional levels of resilience. This research facilitates a deeper understanding of the intricacies and complex interconnectedness of organizational supply chains by monetarily quantifying changes in network resilience. The developed Area under the Curve metric (AUC) is used to quantify the level of demand that each asset allocation can meet during a disruptive event. Due to its applicability across multiple domains, the USAF F-16 repair network in the Pacific theater (PACAF) is modeled utilizing discrete event simulation and used as the illustrating example. …

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Ground Weather Radar Signal Characterization Through Application Of Convolutional Neural Networks, Stephen M. Lee Mar 2020

Ground Weather Radar Signal Characterization Through Application Of Convolutional Neural Networks, Stephen M. Lee

Theses and Dissertations

The 45th Weather Squadron supports the space launch efforts out of the Kennedy Space Center and Cape Canaveral Air Force Station for the Department of Defense, NASA, and commercial customers through weather assessments. Their assessment of the Lightning Launch Commit Criteria (LLCC) for avoidance of natural and rocket triggered lightning to launch vehicles is critical in approving space shuttle and rocket launches. The LLCC includes standards for cloud formations, which requires proper cloud identification and characterization methods. Accurate reflectivity measurements for ground weather radar are important to meet the LLCC for rocket triggered lightning. Current linear interpolation methods for ground …

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Flight Characteristic Verification Of The Variable Camber Compliant Wing, Sharee B. Acosta Mar 2020

Flight Characteristic Verification Of The Variable Camber Compliant Wing, Sharee B. Acosta

Theses and Dissertations

Morphing wing technology gives aircraft the ability to change wing shape to control the aircraft and flight performance characteristics. AFIT, AFRL and USU Aero Lab have collaborated to design and test a variable camber compliant wing (VCCW) on a small unmanned aerial vehicle (UAV). Flight tests demonstrated the wing performance and provided data to refine a VCCW flight simulator. Work was completed with the USU AeroLab-generated MachUp and the actual flight data to improve the simulator to provide results close to those of the actual flight test. The research provides a tool to reduce time and cost for future flight …

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A Comparative Evaluation Of The Detection And Tracking Capability Between Novel Event-Based And Conventional Frame-Based Sensors, James P. Boettiger Mar 2020

A Comparative Evaluation Of The Detection And Tracking Capability Between Novel Event-Based And Conventional Frame-Based Sensors, James P. Boettiger

Theses and Dissertations

Traditional frame-based technology continues to suffer from motion blur, low dynamic range, speed limitations and high data storage requirements. Event-based sensors offer a potential solution to these challenges. This research centers around a comparative assessment of frame and event-based object detection and tracking. A basic frame-based algorithm is used to compare against two different event-based algorithms. First event-based pseudo-frames were parsed through standard frame-based algorithms and secondly, target tracks were constructed directly from filtered events. The findings show there is significant value in pursuing the technology further.

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One-Dimensional Multi-Frame Blind Deconvolution Using Astronomical Data For Spatially Separable Objects, Marc R. Brown Mar 2020

One-Dimensional Multi-Frame Blind Deconvolution Using Astronomical Data For Spatially Separable Objects, Marc R. Brown

Theses and Dissertations

Blind deconvolution is used to complete missions to detect adversary assets in space and to defend the nation's assets. A new algorithm was developed to perform blind deconvolution for objects that are spatially separable using multiple frames of data. This new one-dimensional approach uses the expectation-maximization algorithm to blindly deconvolve spatially separable objects. This object separation reduces the size of the object matrix from an NxN matrix to two singular vectors of length N. With limited knowledge of the object and point spread function the one-dimensional algorithm successfully deconvolved the objects in both simulated and laboratory data.

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Developing A Serious Game To Explore Joint All Domain Command And Control, Nathaniel W. Flack Mar 2020

Developing A Serious Game To Explore Joint All Domain Command And Control, Nathaniel W. Flack

Theses and Dissertations

Changes in the geopolitical landscape and increasing technological complexity have prompted the U.S. Military to coin Multi-Domain Operations (MDO) and Joint All-Domain Command and Control as terms to describe an over-arching strategy that frames the complexity of warfare across both traditional and emerging warfighting domains. Teaching new and advanced concepts associated with these terms requires both innovation as well as distinct education and training tools in order to realize the cultural change advocated by senior military leaders. BSN, a Collectible Card Game, was developed to teach concepts integral to MDO and initiate discussion on military strategy.

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Maximizing Accuracy Through Stereo Vision Camera Positioning For Automated Aerial Refueling, Kirill A. Sarantsev Mar 2020

Maximizing Accuracy Through Stereo Vision Camera Positioning For Automated Aerial Refueling, Kirill A. Sarantsev

Theses and Dissertations

Aerial refueling is a key component of the U.S. Air Force strategic arsenal. When two aircraft interact in an aerial refueling operation, the accuracy of relative navigation estimates are critical for the safety, accuracy and success of the mission. Automated Aerial Refueling (AAR) looks to improve the refueling process by creating a more effective system and allowing for Unmanned Aerial Vehicle(s) (UAV) support. This paper considers a cooperative aerial refueling scenario where stereo cameras are used on the tanker to direct a \boom" (a large, long structure through which the fuel will ow) into a port on the receiver aircraft. …

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Magslam: Aerial Simultaneous Localization And Mapping Using Earth's Magnetic Anomaly Field, Taylor N. Lee, Aaron J. Canciani Mar 2020

Magslam: Aerial Simultaneous Localization And Mapping Using Earth's Magnetic Anomaly Field, Taylor N. Lee, Aaron J. Canciani

Faculty Publications

Instances of spoofing and jamming of global navigation satellite systems (GNSSs) have emphasized the need for alternative navigation methods. Aerial navigation by magnetic map matching has been demonstrated as a viable GNSS‐alternative navigation technique. Flight test demonstrations have achieved accuracies of tens of meters over hour‐long flights, but these flights required accurate magnetic maps which are not always available. Magnetic map availability and resolution vary widely around the globe. Removing the dependency on prior survey maps extends the benefits of aerial magnetic navigation methods to small unmanned aerial systems (sUAS) at lower altitudes where magnetic maps are especially undersampled or …

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Explaining Weapon System Sustainment's Impact To Aircraft Availability, Michael D. Ingram Mar 2020

Explaining Weapon System Sustainment's Impact To Aircraft Availability, Michael D. Ingram

Theses and Dissertations

This research focused on understanding the phenomena behind the cost growth of Weapon System Sustainment (WSS) and the simultaneous degradation in USAF aircraft system availability. The primary modelling technique used was Ordinary Least Squares (OLS) while incorporating temporal effect. Other studies have looked at cost factors related to the Flying Hour Program, flying conditions and age. This study found empirical relationships between each of the four WSS business processes and the lead time in months it takes to realize improvements in system aircraft availability.

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Use Of Lidar In Automated Aerial Refueling To Improve Stereo Vision Systems, Michael R. Crowl Mar 2020

Use Of Lidar In Automated Aerial Refueling To Improve Stereo Vision Systems, Michael R. Crowl

Theses and Dissertations

The United States Air Force (USAF) executes five Core Missions, four of which depend on increased aircraft range. To better achieve global strike and reconnaissance, unmanned aerial vehicles (UAVs) require aerial refueling for extended missions. However, current aerial refueling capabilities are limited to manned aircraft due to technical difficulties to refuel UAVs mid-flight. The latency between a UAV operator and the UAV is too large to adequately respond for such an operation. To overcome this limitation, the USAF wants to create a capability to guide the refueling boom into the refueling receptacle. This research explores the use of light detection …

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Wireless Sensor Network Optimization For Radio Tomographic Imaging, Grant T. Nafziger Mar 2020

Wireless Sensor Network Optimization For Radio Tomographic Imaging, Grant T. Nafziger

Theses and Dissertations

Radio tomographic imaging (RTI) is a form of device-free, passive localization (DFPL) that uses a wireless sensor network (WSN) typically made up of affordable, low-power transceivers. The intent for RTI is to have the ability to monitor a given area, localizing and tracking obstructions within. The specific advantages rendered by RTI include the ability to provide imaging, localization, and tracking where other well developed methods like optical surveillance fall short. RTI can function through optical obstructions such as smoke and even physical obstructions like walls. This provides a tool that is particularly valuable for tactical operations like emergency response and …

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Design, Development, And Testing Of A Low Cost, Additively-Manufactured, Centrifugal Compressor, Aaron P. Bauer Mar 2020

Design, Development, And Testing Of A Low Cost, Additively-Manufactured, Centrifugal Compressor, Aaron P. Bauer

Theses and Dissertations

The three objectives of this research were to: 1.) design, build, and test AM compressors to substitute into COTS micro-gas turbine engines, 2.) provide initial correlations between FEA and compressor failure speed, and 3.) characterize the effects of AM on compressor performance. These goals improved the design cycle cost and the design-validation time cycle. ULTEM 9085, 300-AMB, and Onyx-Kevlar temperature-dependent tensile properties were measured. FEA-predicted failure speeds of stock compressor designs led design improvements, potentially fulfilling the original compressor requirements. Physical testing of the stock and ULTEM 9085 compressors occurred. Comparing these compressors' performances demonstrated that low cost, AM materials …

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The Effect Of Passive And Active Boundary-Layer Fences On Delta Wing Performance At Low Reynolds Number, Anna C. Demoret Mar 2020

The Effect Of Passive And Active Boundary-Layer Fences On Delta Wing Performance At Low Reynolds Number, Anna C. Demoret

Theses and Dissertations

The effect of passive and active boundary-layer fences (BLFs) on performance is evaluated on a NACA 0012 delta wing (croot = 14in, ctip = 2.8in, Λ = 45°, b = 23.5in) at a Reynolds number (Re) of 5.0 x 105 based on the root chord. The performance improvements of a passive BLF are replicated and improved upon using an active flow control (AFC) fluidic fence created by a wall-normal steady-blowing jet from a slot. The application of a passive BLF at a spanwise location of 70% z/b resulted in an 8.7% increase in CLmax compared to …

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Effects Of High Freestream Turbulence And Conduction On Film Cooling Effectiveness Of Shaped Holes, Richard A. Macias Jr. Mar 2020

Effects Of High Freestream Turbulence And Conduction On Film Cooling Effectiveness Of Shaped Holes, Richard A. Macias Jr.

Theses and Dissertations

With technological advancements allowing higher turbine temperatures, film cooling continues to be an important research area. The Film Cooling Rig (FCR) was fitted with a turbulence generator to vary freestream turbulence intensity and length scale, enabling the effects of high freestream turbulence on overall effectiveness to be studied. A cylindrical hole and laidback fan-shaped hole were investigated over a range of Advective Capacity Ratio (ACR) for freestream turbulence intensities of 2%, 10%, and 15%. For a given ACR, increasing the turbulence intensity resulted in lower overall effectiveness values due to the larger heat transfer coefficient that comes from turbulent ow. …

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