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 …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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 …

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, …

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 …

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 …

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 …

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

Theses and Dissertations

Copyright held by author

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 …

Additively Manufactured Lenses For Modulating Guided Waves In Laminated Composites, Hajar Righi

Theses and Dissertations

Composite materials have increasingly been used as an alternative to metals and other isotropic materials for primary structural components in aerospace industries. Unlike traditional isotropic materials, composite materials are known to have complex internal microstructures. Therefore, it is essential to develop methods for the inspection, evaluation, and monitoring of composite materials. Ultrasonic-guided waves and, more precisely, Lamb waves have proven to be an efficient and accurate technique for the non-destructive testing. Since guided waves are dispersive and multimodal, it is important to develop a practical method to manipulate Lamb waves to achieve better structural health monitoring and non-destructive inspection results. …

Quasi 1d Modelling Of A Scramjet Engine Cycle Using Heiser-Pratt Approach, Asmaa Chakir

Theses and Dissertations

Scramjet engines are key for sustained hypersonic flights. Analytic models play a critical role in the preliminary design of a scramjet engine configuration. The objective of this research is to develop and validate a quasi-1D model for the scramjet engine encompassing inlet, isolator and combustor, to evaluate the impact of flight conditions and design parameters on the engine functionality. The model is developed assuming isentropic flow in the inlet with a single turn; modified Fanno-flow equations in the isolator that account for the area change of the core flow; and the combustor is modeled using Heiser-Pratt equations accounting for the …

Analysis Of Proposed Active Radiation Shielding Design Concept For Spacecraft, Claire Mechmann

Theses and Dissertations

A need exists to protect the crew of interplanetary spacecraft from lethal doses of Galactic Cosmic Radiation (GCR) and Solar Energetic Particles (SEPs). As plans progress to send humans beyond lower Earth orbit (LEO) and outside of Earth’s protective magnetosphere, agencies involved in this endeavor find themselves confronted with the obstacle of shielding the crew from this harmful radiation. A proposed active shielding concept design has been suggested, utilizing charged dielectric capacitors to deflect incoming charged particles. This analysis will examine the feasibility of the proposed design and offer potential materials useful for application. The results should prove informative for …

Comparison Of Stability And Control Characteristics Of The Pipistrel Virus Sw And Pipistrel Velis Electro, Sean Gregory Gunther

Theses and Dissertations

This document finds the stability and control affects of electric powerplant conversion on a pre-existing internal combustion powered Pipistrel Virus SW through comparison with the Pipistrel Velis Electro. Testing included analysis of both static and dynamic stability on the longitudinal and lateral-directional axes of the airplane. Due to the light sport airplane being used in testing, some of the intedended tests were unable to be performed, however, conclusions were still capable of being made. The primary conclusion is that electric conversion of an airframe has no significant negative consequences, with the airplane still exhibiting positive stability on all three axes. …

Stress-Based Topology Optimization Of Pi Preform-Bonded Composite Laminate Structure, Iwan Broodryk

Theses and Dissertations

The purpose of this work is to explore the stress-based topology optimization of structure that utilizes laminated composites and 3D woven Pi preform joints. Simple geometry, loading, and boundary conditions are considered. At a finite element level, an aggregate stress ratio is developed for Pi joint and acreage laminate elements. A basic descent method of moving asymptotes (BDMMA) algorithm is created to solve all optimization problems. Topology results for two different stress-based formulations and a compliance minimization problem are compared, followed by an in-depth analysis at a Pi joint and laminate level.

Characterizing Climb And Propeller Performance For A Fixed Pitch, Single-Engine, Electric Aircraft, Austin Lawrence Andwan

Theses and Dissertations

Electric aircraft are on the horizon. Both industry and regulators have an abundance of flight tests ahead to ensure safe operation of these new aircraft. Conventional performance standards regaurding edurance, climb performance and cruise conditions are largely not applicable to assessing an electrically propulsed aircraft. While battery technologies are the current barrier for electric aircraft, there also hasn’t been much flight testing to reveal their unique performance trends. This experiment focus’s on characterizing some of these performance trends obtained through a level flight and climb test in the Pipistrel Velis Electro. The rate-of-climb did not exhibit a decrease when the …

Piper Pa-28-181 Archer Iii Tail #931ec Flight Test Stability, Control And Performance, Steven Allan Sutton

Theses and Dissertations

The following flight test was conducted as part of the culmination requirement for the Master of Science, Flight Test Engineer degree program from Florida Institute of Technology. The flight was conducted to gather data and produce a flight test report on the data gathered. The flight test plan consisted of a series of both Stability and Handling test point as well as basic aircraft performance points. The testing was planned to be accomplished over a single flight, for reasons discussed later in this report. The flight departed on the morning of 26 September, 2022 out of Bob Sikes Airport, KCEW, …

Accelerated Aging Of Adhesively Bonded Composite Joints For Use In Material Screening And Selection During Development: A Review And Case Study, Marie Danielle Flanigan

Theses and Dissertations

Adhesively bonded structures are used in many high-tech industries such as aerospace, automotive, and defense. The application of these joints using composite adherends has increased in recent years because of improved strength-to-weight ratio, design flexibility, and lower concern for corrosion. Quality acceptance of these structures largely depends on reliability and durability which includes influence of environmental service conditions on long-term behavior. Characterization of long-term behavior presents a difficult challenge to those involved in material selection and design due to the long service life of the joint compared to the development time available and complexity of the degradation mechanisms. Therefore, different …