Engineering Commons^™

Investigation And Control Of Görtler Vortices In High-Speed Flows, Omar Es-Sahli

Theses and Dissertations

High-amplitude freestream turbulence and surface roughness elements can excite a laminar boundary-layer flow sufficiently enough to cause streamwise-oriented vortices to develop. These vortices resemble elongated streaks having alternate spanwise variations of the streamwise velocity. Following the transient growth phase, the fully developed vortex structures downstream undergo an inviscid secondary instability mechanism and, ultimately, transition to turbulence. This mechanism becomes much more complicated in high-speed boundary layer flows due to compressibility and thermal effects, which become more significant for higher Mach numbers. In this research, we formulate and test an optimal control algorithm to suppress the growth rate of the aforementioned …

Experiments And Simulations Of Liquid Mass Gauging And Slosh Dynamics In Microgravity, Jedediah Morse Storey

Theses and Dissertations

Advancements in liquid propellant management science and technologies are key to increasing safety, decreasing cost, and increasing payload mass of space missions. Propellant usually comprises a large portion of the total mass of launch vehicles and spacecraft, so liquid propellant sensing, as well as predicting and controlling the motion of it, are important. Electrical Capacitance Tomography (ECT) is an emerging sensing technology that is capable of measuring the distribution of liquid anywhere inside of a tank, potentially making it useful for measuring slosh and gauging mass. An ECT-instrumented tank was successfully tested in microgravity for the first time. Basics of …

Optimization Of High-Order Statistical Moment Combinations To Best Represent Spray Flow Particle Probability Density Functions, Amanda Lynn Myers

Theses and Dissertations

Characterizing spray flows has been an issue of interest for years, particularly in regards to fuel injection in engines. Droplet velocity and diameter, among other characteristics, are crucial to understanding spray flows. One approach for determining these quantities in a spray is using a statistical approach that solves for the moments of droplet characteristics as they evolve in space and time. A theoretical probability density function (PDF) can be formulated using various combinations of moments which evolve according to derived moment transport equations (thus evolving the PDF), using the principle of maximum entropy as closure to the system. Building upon …

Stability And Control Flight Testing Of A Modified Cessna 172, Tatiana Dirrigl Forbes

Theses and Dissertations

The Cessna 172N is a small, fixed-wing, single-engine aircraft. The modified Cessna 172N included a swapped engine to a Lycoming O-360-A4M, tuned exhaust, and variable timing ignition installed. Test flights on this aircraft were performed order to evaluate the stability and control characteristics of the Cessna 172N, and compare them with the regulations in the Title 14 CFR Part 23 Airworthiness Standards for Normal, Utility, Acrobatic, and Commuter Category Airplanes. The flight test consisted of four separate tests performed during a single flight, departing from and returning to Melbourne Orlando International airport (KMLB). The data was collected through static and …

Accelerating Machine Learning Inference For Satellite Component Feature Extraction Using Fpgas., Andrew Ekblad

Theses and Dissertations

Running computer vision algorithms requires complex devices with lots of computing power, these types of devices are not well suited for space deployment. The harsh radiation environment and limited power budgets have hindered the ability of running advanced computer vision algorithms in space. This problem makes running an on-orbit servicing detection algorithm very difficult. This work proposes using a low powered FPGA to accelerate the computer vision algorithms that enable satellite component feature extraction. This work uses AMD/Xilinx’s Zynq SoC and DPU IP to run model inference. Experiments in this work centered around improving model post processing by creating implementations …

Task Optimization Utilizing Digital Transformation Concepts - Automation Project Execution Via Agile Methodology, Anthony Steven Maiello

Theses and Dissertations

Task Optimization via the use of automated process improvements is becoming more widespread as more industries lean into the concepts surrounding digital transformation. This shift also necessitates a complementary adaptation in project management methodologies to support the rapid and ever-changing environment, requirements, and innovations. This thesis examines the effectiveness of Agile methodology in managing digital automation projects, with a specific focus placed on process improvements with systems engineering. It accomplished this by contrasting the original model, designed and derived utilizing traditional project management techniques, with the proposed model which is a direct result of the application of Agile project practices. …

Gpu Based Monte Carlo Estimation Of Eddy Current Losses In Electromagnetic Coil-Core System, Adwaith Ravichandran

Theses and Dissertations

A novel parallelizable probabilistic approach to model eddy currents in AC electromagnets is presented in this research. Consequently, power loss associated with the formation of these eddy currents is estimated and validated using experimental data. Furthermore, predicting the effect of ferromagnetic alternating field enhancement on power loss in the source excitation winding has been an active area of research. Unlike a stationary field, an alternating sinusoidal field diffuses partially into the ferromagnetic material leading to a predictably sub-optimal field enhancement. To model these physics, finite element techniques employ nonlinear iterative solvers which are time consuming. A novel method is developed …

A New Algorithm For Encounter Generation: Encounters From Actual Trajectories (Enact), James Anthony Ritchie Iii

Theses and Dissertations

There is ongoing research at the Federal Aviation Administration (FAA) and other private industries to examine a concept for delegated separation in multiple classes of airspace to allow unmanned aircraft systems (UAS) to remain well clear of other aircraft. Detect and Avoid (DAA) capabilities are one potential technology being examined to maintain separation. To evaluate these DAA capabilities, input traffic scenarios are needed, but current approaches are limited by the breadth of the traffic recordings available. This thesis derives a new mathematical algorithm that uses great circle navigation equations in an Earth spherical model and an accurate aircraft performance model …

Design Of A Test Frame And Its Corresponding Test Methods For A Deployable Composite Boom, William Luther Montgomery

Theses and Dissertations

Deployable composite booms (DCB) are an advanced class of support beams growing in applications including solar collectors and solar sails. DCBs can be coiled or folded into a compact footprint and the ability to be deployed, and in some design, concepts redeployed, making them optimal components for aerospace where weight and volume are finite resources. DCBs are a cutting-edge technology that has yet to be perfected with a need for longer booms with increased stiffnesses to accommodate the latest proposed designs. Atomic-6 has proposed a 16-foot boom manufactured using an autoclave process which aims to reach the goal of producing …

Uav-Deployable Sensing Network For Rapid Structural Health Monitoring, Joud Satme

Theses and Dissertations

Natural disasters and extreme weather events pose significant threats to the structural integrity and safety of civil and environmental infrastructure. In this context, Structural Health Monitoring (SHM) emerges as a pivotal discipline, intersecting engineering, technology, and disaster resilience. SHM's mission is to provide real-time, data-driven insights into the condition of critical infrastructure, encompassing bridges, buildings, dams, and transportation networks. These systems not only expedite assessment, but also wield substantial influence in mitigating catastrophic disasters. As the frequency and intensity of extreme weather conditions escalate due to climate change, the need for robust and proactive SHM strategies becomes increasingly apparent. Moreover, …

Uncertainty Quantification And Constraint Of Chemical Kinetic Mechanisms Based On Flow Reactor Experiments, Ana Victoria Kock

Theses and Dissertations

The chemical kinetic model is one of key sub-models for computational fluid dynamics (CFD) simulation for optimizing and designing various combustors/engines. Detailed chemical kinetic models can consist of hundreds of species and thousands of elementary reaction steps. Considering the complexity in these detailed chemical kinetic models, it is important to quantify and minimize the uncertainties in the kinetic parameters. The uncertainties in the kinetic models can then be compared to uncertainties tied to experimental measurements. This approach has been frequently applied for relatively simple combustion parameters (e.g., laminar flame speed, ignition delay time), however it has not been well utilized …

Application Of An Adaptive Controller On An Air-Bearing Vehicle-Manipulator System, Samuel Thomas Lovelace

Theses and Dissertations

The growing demand for on-orbit servicing and assembly as well as orbital debris capture and removal poses many engineering challenges. One primary challenge is that of position and attitude control of a spacecraft-manipulator system while performing these operations. Standard control approaches may be used for cases where the dynamics of the objects that the spacecraft-manipulator system interacts with are known are still plausible. However, there will likely be some uncertainty and lack of knowledge of the dynamic properties of orbital debris and parts required for servicing. Therefore, many have proposed the use of adaptive control schemes which can recalculate the …

Analysis Of The Performance, Recertification, And Sustainability Of A Cessna 172n Modified With An O-360-A4m Powerplant, Variable Timing Electronic Ignition, And Tuned Exhaust, Kelsey Lee Kaht

Theses and Dissertations

The purpose of this thesis is to discuss the performance, modification, and recertification of the test aircraft, a Cessna 172N that has been equipped with an O-360-A4M power plant, tuned exhaust, and variable timing electronic ignition, and to compare the aircraft to a stock aircraft and other high-performance aircraft to determine the feasibility of the modifications. 65 knot, 80 knot, and 95 knot steady state climb and 2000 ft and 5000 ft level acceleration tests were performed with the test aircraft at the Melbourne Orlando International Airport. The weather was clear with calm wind, and there was only one issue …

Evaluation Of Early Maturing Cultivars, Optimal Harvest Timing, And Canopy Reflectance Of Peanut To Maximize Grade And Yield, Joseph Bryan Whittenton

Theses and Dissertations

Peanut digging timing is difficult to predict due to indeterminate growth and peanut pods maturing underground, resulting in the need to research methods that provide consistent measurements, while reducing time and effort for farmers and researchers. Experiments were conducted to evaluate the accuracy of the Maturity Index 1 and Maturity Index 2 in predicting peanut grade, the accuracy of the North Carolina 2 degree day method in predicting peanut yield, and remote sensing vegetative indices sensitivity equivalence (SEq) to peanut Maturity Index 2 and harvest grade (TSMK) for cultivars IPG-914 and Georgia-06G in Mississippi.

Maturity Index 1 and …

Climb Performance Testing Of The Pa-28-180 Utilizing Saw-Tooth Method And Level Acceleration Method, Paige Elizabeth Christensen

Theses and Dissertations

This thesis details the test methods, data reduction methods, and flight data analysis conducted in the climb performance evaluation of the PA-28-180 “Piper Arrow.” The main objective of this thesis was to quantitatively compare the climb performance requirements detailed in the former regulation, CAR 3.85a to the current regulation, 14 CFR 23.2120, utilizing Saw-Tooth steady climb method conducted at various airspeeds. The report also evaluates the Level Acceleration method at reciprocating headings, and qualitatively assesses the usefulness of testing multiple headings on a general aviation aircraft at multiple altitudes. The Saw-Tooth Climb and Level Acceleration flights were conducted on January …

Modeling Of Turbulent Flow In Pipe Systems With Compound Bends, Stella Smithe

Theses and Dissertations

A practical CFD k-epsilon realizable model is applied to four pipe systems with various 90° bend configurations to examine velocity profile evolution and total pressure losses within the pipe systems. The pipe systems compared are a configuration with a single 90° L-bend, as well as three additional pipe configurations composed of dual 90° bends, all with total length x/D=16.7. The dual bend configurations studied are: a 180° turning U-bend, a 0° total turning S-bend, and a dual 90° out-of-plane, compound C-bend. The CFD model was benchmarked against experimental data from a straight pipe and a pipe configuration with a single …

Flight Test Evaluation Of The B-1b Lancer For The Heavy Bomber Mission, Robert William Gates

Theses and Dissertations

Copyright held by author

Smartphone Video Guidance Sensor In High-Altitude Uav Precision Landing, Joao Leonardo Silva Cotta

Theses and Dissertations

The Smartphone Video Guidance Sensor (SVGS) is an emerging technology developed by NASA Marshall Space Flight Center that uses a vision-based approach to accurately estimate the six-state position and orientation vectors of an illuminated target of known dimensions with respect to a coordinate frame fixed to the camera. SVGS is a software-based sensor that can be deployed using a host platform’s resources (CPU and camera) for proximity operations and formation flight of drones or spacecraft. The SVGS output is calculated based on photogrammetric analysis of the light blobs in each image; its accuracy in linear and angular motion at different …

Rendezvous And Proximity Operations In Cis-Lunar Space, Khalid Jebari

Theses and Dissertations

As interest in Moon exploration grows and efforts to establish an orbiting outpost intensify, accurate modeling of spacecraft dynamics in cis-lunar space is becoming increasingly important. Contrary to satellites in Low Earth Orbit (LEO) where it takes around 5 ms to communicate back and forth with a ground station, in the Moon’s orbit it can take up to 2.4 seconds to do so. This delay in communication can make the difference between a successful docking and a catastrophic collision for a remotely controlled satellite. Moreover, due to the unstable nature of trajectories in cis-lunar space, it is necessary to design …

Determining Performance Characteristics From The Mississippi Cowling - Piper Warrior Vs. Piper Archer, Soufiane Ait Yahia

Theses and Dissertations

Today, Piper is one of the most used aircraft in the general aviation sector. The history of Piper Aircraft has been the subject of numerous books and research projects with over 80 years of aviation industry leadership. For aviation fanatics, the Cherokee is synonymous with Piper Aircraft Corporation. The Piper PA-28 Cherokee is a family of two-seat or four-seat light aircraft built for air taxi, flight training, and personal use. The original Piper Cherokees PA-28- 150 and PA-28-160 received their type certificate from the Federal Aviation Administration back in 1960 and the series remains in production to this day. Multiple …

A Study To Determine Performance Characteristics Of The Mississippi Cowling - Piper Archer Vs. Piper Warrior, Zilvinas Visockas

Theses and Dissertations

Today, aviation is one of the most technologically advanced and innovative sectors in the world. With fast-depleting natural resources, increasing environmental pollution, and continuous growth in fuel cost, efficiency has become industry’s top priority. Engineers are making gradual improvements that offer overall increase in aircraft’s performance. Drag is critical factor in aviation as it directly impacts aircraft’s fuel efficiency, range, and speed. During the design phase, engineers invest significant effort and expense in attempting to minimize the drag profile by implementing aerodynamic shapes and constantly reducing component weights. One of the real-life examples of such engineering attempts is Piper Archer, …

The Effect Of Biodiesel Blend Composition On Jet Aircraft Airframe Fuel System Components & Materials, Elise Aurora Medhus

Theses and Dissertations

In the aviation industry, biodiesel is a clean-burning alternative to petroleum-based jet fuel and has been shown to reduce particle emissions from aircraft engines. This thesis studies the impact of biodiesel on aircraft airframe fuel system components & materials with corrosion-resistant surface treatments. The goal is to identify areas for optimization to increase the use of higher blends in jet aircraft engines to further reduce emissions. The work performed involved testing the corrosion resistance of several aluminum samples, steel samples, and non-metallic materials in numerous biodiesel blends ranging from B05 to B100. The testing method used was the Assessment of …

Trajectory Energy Management For Ectol: Examination Of Battery Discharge Under Two Flight Profiles, Denner Campos Cunha

Theses and Dissertations

The expanding industry of electric airplanes presents a significant regulatory challenge for aviation authorities worldwide. The first step towards achieving a precise Trajectory Energy Management (TEM) is to understand how the powertrain behaves during the operation. Therefore, this work examined the battery performance of an eCTOL, the Pipistrel Velis Electro, under two different prescribed flight profiles and take-off weights. Flight 1, a destination trip profile, was conducted with a gross weight of 1146 lbs and a constant power setting of 22 kW during the cruise segment, while Flight 2, a local training flight profile, was conducted with a gross weight …

Accident Investigation On In-Flight Loss Of Control Due To Configuration Change On Piper Arrow, Basilio Caruso

Theses and Dissertations

Between 2012 and 2021, NTSB has identified over 2200 accidents due to loss of control. The majority of which happened while flying in the pattern. The most challenging phase of a flight is the take-off and landing. During these phases, the pilot initiates a change of configuration of the airplane by lowering or retracting the flaps. Lowering the flaps slows down the plane and increases the lift of the wing but also changes the longitudinal free response of the aircraft. The pitch changes of the plane require the pilot to promptly compensate to keep straight and level flight and avoid …

Evaluation Of Preferential Vaporization Characteristics Of Isolated Single Droplet Combustion In A Converging Channel, Claire Elizabeth Dixon

Theses and Dissertations

Preferential vaporization of isolated single droplets was evaluated in this study. A previously verified lab-scale experiment using flow acceleration to counteract the effects of buoyancy in a converging channel with a decreasing cross section was utilized to investigate the single isolated droplet combustion. The previous experimentation revealed differences between results and values predicted by a one-dimensional numerical simulation. To investigate if the observed differences were the result of turbulent flow and the development of a boundary layer within the channel, a model was designed and analyzed in Ansys Fluent.

The developed Ansys simulation indicated that turbulent flow and growth of …

Actuation And Sensing Applications Of Piezoelectric Transducers, Connor Griffin

Theses and Dissertations

Piezoelectric materials, defined by their ability to display a charge across their surface in response to mechanical strain, are great for use in actuation and sensing applications. Actuation applications include acoustic devices, motors and vibration damping while sensing applications include pressure sensors, medical devices, energy harvesting and structural health monitoring (SHM). The use of piezoelectric actuation and sensing across the lifecycle of aerospace metals is currently an expanding field with use cases beginning with the manufacturing process and ending with SHM.

The research presented in this thesis had three goals: (i) to develop methods for implementation of piezoelectric actuation in …

Belief Space Planning For Alternative Navigation In Gnss-Denied Environments, Timothy I. Machin

Theses and Dissertations

Robust alternative navigation for autonomous agents becomes critical without reliable GNSS. Autonomous agents utilize measurement updates to constrain uncertainty. Belief space planning builds graph structures of beliefs within environments based on probable paths, agent and measurement models, and information of the environment. The Rapidly-exploring Random Alt-Nav Belief Graph (RRBANG) algorithm leverages stochastic filtering to implement a range of alt-nav measurement capabilities for robust navigation in GNSS-denied environments.

Estimation Of Optimal Flight Trajectory In A Total Power Loss Scenario Using Proximal Policy Optimization, Eidahn Eliash

Theses and Dissertations

Recent research has been conducted in using deep reinforcement learning algorithms to generate closed form optimal control laws for helicopters in power loss scenarios. The control laws could allow for design of various cockpit visual pilot aids if proven successful. Such pilot aids are predicted to reduce pilot workload during execution of an emergency powerless landing, and to overall increase the probability of landing safely in such an event. The proposed topic discusses the use of the PPO algorithm in order to find an optimal control policy for a helicopter in a total power loss emergency landing scenario. The task …

Experimental And Computational Bearing Strength Of Fiber Metal Laminate With And Without Film Adhesive, Christopher L. Bellanova Jr.

Theses and Dissertations

This research characterized the performance of a fiber metal laminate composed of carbon fiber and stainless steel without film adhesive and compared it to a similar, previously tested, fiber metal laminate including film adhesive. Removal of the adhesive layers reduced the localized thickness, simplified manufacturing, and allowed for a 20% increase in foil thickness. Quasi-static testing was conducted in double shear, single shear protruding, and single shear countersunk configurations. The results were compared to adhesive hybrid and control samples. To study the affects of bolt tension, samples at low torque in double shear were also tested. Progressive failure samples revealed …

Concept Of Operations Of Cislunar Mirror Satellites To Provide Augmented Lighting Of Dim Space-Based Objects, Alec E. Cook

Theses and Dissertations

The imaging and inspection of Resident Space Objects (RSOs) is an increasingly important mission as space-faring nations and commercial enterprises alike seek to develop means to repair and refuel spacecraft, as well as de-orbit RSOs to reduce orbital debris. Lighting conditions are not always advantageous for an imaging/inspection or repair/refuel spacecraft; therefore, the use of mirror spacecraft to reflect solar energy is proposed to illuminate dimly lit RSOs. The present research investigates the efficacy of space-based reflectors at examining spacecraft in the cislunar environment. Specific assessments include target spacecraft in geosynchronous Earth orbit and periodic orbits around selected Lagrange points, …