Engineering Commons^™

Comparison Of Rans Modeling To Dual-Plane Piv Measurements Of The Turbulent Tip Vortex Trailed From A Hovering Rotor, Zachary Lietzau

Doctoral Dissertations and Master's Theses

Numerical simulations using the Reynolds-Averaged Navier-Stokes (RANS) equations were conducted to study the development and turbulent decay of the tip vortices in the wake produced by a hovering rotor. The computational results were compared to detailed, dual plane Particle Image Velocimetry (PIV) measurements of a turbulent tip vortex trailed from a single-bladed rotor. The work investigated both the required mesh resolution and most suitable turbulence closure models with rotational/curvature corrections by assessing their predictions of the tip vortex properties and the overall physical nature of the rotor wake. It was found that even when using a higher-order accurate central differencing …

Supervisory Controls Strategy To Reduce Utility Factor Weighted Criteria Emissions For A Plug-In Hybrid Electric Vehicle, Thomas Francis Gorgia Iii

Doctoral Dissertations and Master's Theses

Criteria emission reduction techniques are being more sought out in the automotive industry due to current government regulation for light duty vehicles. Parallel-series plug in hybrid electric vehicles can have multiple strategies to balance emissions and fuel consumption. Common controls strategies in industry target fuel economy by using a large electric vehicle range, known as charge depletion, followed by maintaining a state of charge after a specific vehicle threshold, or charge sustaining. A charge preserve strategy works by running an engine at an optimal loading condition, the engine will burn the fuel more complete reducing criteria emissions. Charge preserve will …

Numerical Investigation Of A Phase-Change Material Based Photovoltaic Panel Temperature Regulation System, Rohit Gulati

Doctoral Dissertations and Master's Theses

As the production of clean electricity has gained importance, photovoltaic (PV) panels have become a widely used technology. But, during operation, PV panels heat up due to the solar insolation and suffer a drop in electrical output. The goal of this investigation is to use phase-change materials (PCM) to passively cool PV panels. The PCM is inside an aluminum container attached to the back surface of the PV panel. Four configurations of the container are investigated. The first configuration is a container with bulk PCM occupying its entire interior volume. The depth of this container is varied. The second configuration …

Electrical Optimization Of A Plug-In Hybrid Electric Vehicle, Andre J. Napier

Doctoral Dissertations and Master's Theses

Hybrid electric vehicles electrification and optimization is a prominent part of today’s automotive industry. GM and the Department of Energy challenge 16 universities across North America to redesign a Chevrolet Camaro into a hybrid electric vehicle. This thesis will address how Embry Riddle Aeronautical University’s EcoCAR team electrified and optimized the vehicle. The objective of the thesis is to optimize the electric portion of the vehicle, particularly the low voltage circuitry. Prior work is discussed in detail on the vehicle communication bus, building the power distribution unit and the approach the electrical team took when building the electric portion of …

Battery Centric Serial Hybrid Aircraft Performance And Design Space, Lenny Gartenberg

Doctoral Dissertations and Master's Theses

The design space and flight envelope of a battery centric serial hybrid aircraft has been analytically derived. The formulation assumes cruising flight only and all energy available is used. The flight envelope can be generated for any conventional propeller driven serial hybrid aircraft. The advantageous combination of an electric motor and controllable-pitch electric propeller was also explored. The results are used to be able to control efficiency and noise at constant thrust and therefore constant airspeed. Manufacturer provided electric motor and propeller data is used for efficiency purposes. Since the electric motor is virtually silent compared to the propeller, published …

Structural Design Of A Business Jet Winglet, Jaime Gutierrez

Doctoral Dissertations and Master's Theses

Structural sizing of a winglet for the Falcon 10 was performed and is presented here. The aerodynamic profile of the winglet was taken from a previous study, which predicted an increase in range of 3.3% with an estimated weight increase of 52 kg. An investigation of the current structure layouts and materials used in the industry was conducted. Six loading cases were analyzed to identify the most critical for the winglet, found to be negative and positive sideslip and gust. A finite element model was developed and used to size the structure. A fabrication process and assembly is described and …

Development Of An Emulated Free-Floating Environment For On-Earth Testing Of Space Robots, Narendran Muraleedharan

Doctoral Dissertations and Master's Theses

The ability to perform experiments on space robotic systems within a laboratory setting is crucial to development and testing of satellites and space robots prior to launch. One of the most widely used techniques which recreate the on-orbit motion of space robots and targets is hardware-in-the-loop simulation. This method requires extensive knowledge of the space robot model dynamic parameters. This research proposes a method which uses force feedback to control a robotic platform on which the space robot is mounted. The robotic platform is driven in such a way that the gravity-compensated forces and torques at the mounting interface are …

Ab Initio Computation Of Radiative Properties Of Monatomic Hydrogen, Fanny Thomas

Doctoral Dissertations and Master's Theses

With renewed interest in planetary atmospheric entry, descent, and landing, NASA has noted a need for improved physics modeling in computational fluid dynamics. Uncertainty in experimental data used in radiation heat transfer computations leads to “over-engineering” of entry body heat shields, at large weight and cost penalties. There is interest in developing hypersonic thermophysics models from the known “first principles” of physics.

A method for computing high temperature gas emissivity and absorptivity from quantum mechanics principles is developed. The Schroedinger wave equation is cast as a discretized matrix eigenvalue problem which is solved using the ERAU parallel supercomputer. The numerical …

Integration Of Macro-Fiber Composite Material On A Low Cost Unmanned Aerial System, May Chong Chan

Doctoral Dissertations and Master's Theses

The development, deployment, and operation of Unmanned Aerial Systems (UAS) have grown exponentially in recent years and have provided researchers with the opportunity to gain hands-on experience with aircraft in a manner that was previously limited to institutions and companies with large budgets. This allows the generation and testing of UAS advanced technologies using low cost systems. The scope of this thesis does not aim to make vast improvements to the control strategy itself, but to expand upon previous UAV work carried out at Embry-Riddle by designing, implementing, and demonstrating a simulation environment for mechanical and Macro-Fiber Composite (MFC) actuated …

Extended Surface Heat Transfer Coefficients Via Endwall Temperature Measurements, Yogesh Pai

Doctoral Dissertations and Master's Theses

Short pins are used for internal cooling of the trailing edge in a gas turbine blade. A novel method is described in this thesis which helps in simplifying the experimental process used to obtain average heat transfer data on the pin surface, at the expense of additional post processing complexity. The method is based on a unique, analytical solution of the longitudinal conduction equation with internal heat generation, allowing computation of heat transfer rates via pin base temperature measurements via Temperature Sensitive Paint, or similar non-intrusive methods. Verification of this method is done with comparisons to the solution of infinite …

The Effect Of Surface Materials And Morphology On Wingsuit Aerodynamics, Timothy Allen Sestak

Doctoral Dissertations and Master's Theses

This study examines the aerodynamic effects of the materials, textiles, and morphologies currently used in wingsuit design and construction. The experiment was a low-speed wind tunnel investigation using a rigid wing with an aspect ratio of 2, a NACA 4418 airfoil cross section and a smooth, polished painted surface as a baseline. The baseline wing was modified by covering the upper and lower surfaces with various textiles currently used in wingsuit construction. This study is the first step in continued research to design and build a wingsuit with superior glide performance compared to current designs. Surface textures and features on …

Applications Of The Technology Acceptance Model To Integration Of The Automatic Ground Collision Avoidance System In Fighter Aircraft Operations, Casey Richardson

Doctoral Dissertations and Master's Theses

The leading cause of F-16 fighter aircraft and fighter pilot losses is ground collisions. In an effort to curb this hazard, an automatic ground collision avoidance system (AGCAS) was formally fielded for use in routine U.S. Air Force active-duty F-16 operations in 2014. AGCAS uses a high-level automation design capable of altering the aircraft’s flight control system independent of pilot action.

This study explored an application of the Technology Acceptance Model (TAM) to integration of the AGCAS in fighter aircraft operations. Using data from a survey of active-duty U.S. Air Force F-16 operational fighter pilots (n=142), collected shortly after initial …

Application Of Neural Networks To Acoustic Localization, Stephen Cronin

Doctoral Dissertations and Master's Theses

The intent of the work conducted was to build a neural network for the purposes of acoustic localization. The target of this localization is a sound source underwater. For our purposes, it is an acoustic pinger, as it produces consistent sound at a fixed rate making it ideal for testing. The network was intended to ingest raw data streams and output location information based on the arrangement of sensors employed. To achieve an accurate network, a simulation factoring in the environment was to be created to produce a data set large and diverse enough to describe the unique parameters of …

Feasibility Of Neural Networks For Maritime Visual Detection On A Mobile Platform, Robert Goring

Doctoral Dissertations and Master's Theses

Object detection through computer vision has traditionally been difficult to reliably implement due to various lighting conditions caused by weather and time of day. Any changes in conditions can be detrimental to the detector’s ability to accurately identify objects. A modern approach implements deep learning techniques to classify and train a neural network. While highly effective, this approach can be cumbersome and computationally intensive. This project will investigate the feasibility of using deep learning to detect, classify, and track objects in near real-time while being processed on a mobile platform. I will investigate the feasibility of these processes on a …

The Extent Of Distraction Of Cell Phone Conversations For Passengers In Simulated Flight, Tianhua Li

Doctoral Dissertations and Master's Theses

Currently, passengers are forbidden from making cell phone calls during flights in the United States due to cellular electronic interference. However, some related research has demonstrated that the use of cell phones has little interference with avionics. Furthermore, any potential electronic interference can be eliminated by using new technology. Although talking on the cell phone does not cause electronic interference, the distraction of a passenger caused by a cell phone may negatively impact safety. The cell phone calls have been found to affect people’s attention and performance. In-flight announcements are popular methods to inform commercial airliner passengers of their situation …

Effects Of Graphical Weather Information Versus Textual Weather Information On Situation Awareness In Meteorology, Stefan Melendez

Doctoral Dissertations and Master's Theses

Prior to a flight, pilots gather meteorological information to assess the weather conditions pertaining to their flight and to make decisions based on it. This information can come in various formats, such as text and graphical weather information. Research has shown that people have varying learning preferences and that most people prefer visual learning to verbal learning (i.e., graphical over text). It is hypothesized that this difference in learning preference can affect the way pilots interpret and apply the information they obtain prior to their flight. The researcher hypothesizes that graphical weather information has a greater, more positive impact on …

Dynamic Understeer Control Using Active Rear Toe, Mark Oliver Dixon Kaufman

Doctoral Dissertations and Master's Theses

This thesis was conducted to show the ability of Active Rear Toe to control the understeer characteristics of a vehicle. Active rear toe is the ability to control the angle of the rear wheels around the vertical axis, allowing the car’s turning radius to change. By changing this radius, the lateral acceleration can be controlled, therefore the understeer of the vehicle can be controlled. The controls scheme is a sliding mode control, specifically a hyperbolic tangent boundary layer and a type 1 zeno controller. The system shows effectiveness to control the understeer of the vehicle up until limit grip on …

Multi-Agent Path Planning For Locating A Radiating Source In An Unknown Environment, Stephanie M. Schwartz

Doctoral Dissertations and Master's Theses

A situation is addressed in which multiple autonomous agents are used to search an unknown environment for a target, the position and orientation of which is known with respect to each agent. A controlling framework is proposed to inform and coordinate the agents’ movements in order to reduce the time required to locate the target. Four primary variables are considered: the cost function used to select the agents’ paths, the number of agents in a given scenario, the distance over which the agents are assumed to communicate, and the size of the environment in which the agents are operating. It …

Collision Avoidance And Navigation Of Uas Using Vision-Based Proportional Navigation, Matthew J. Clark

Doctoral Dissertations and Master's Theses

Electro-optical devices have received considerable interest due to their light weight, low cost, and low algorithm requirements with respect to computational power. In this thesis, vision-based guidance laws are developed to provide sense and avoid capabilities for unmanned aerial vehicles (UAVs) operating in complex environments with multiple static and dynamic collision threats. These collision avoidance guidance laws are based on the principle of proportional navigation (Pro-Nav), which states that a UAV is on a collision course with another vehicle or object if the line-of-sight (LOS) angles to the object remain constant. The guidance laws are designed for use with monocular …

Computational Modeling Of Thoracic Injury Response Due To Impact Of A Small Unmanned Aerial System (Suas), Alexander Fumiyoshi Dori

Doctoral Dissertations and Master's Theses

This study aims to establish a computational model that will predict the injury response after a sUAS impacts the thorax. A rotary and fixed winged sUAS were chosen for analysis. A vast number of numerical simulations were carried out with varying masses, impact velocities, and impact angles. From the simulation results, the maximum viscous criterion was then calculated. A nonlinear surrogate model was established by setting the impact parameters as independent variables and the viscous criterion as the dependent variable. A correlation analysis showed the impact velocity and angle to significantly influence the results more, when compared to the mass. …

Bio-Mimicry Of A Leopard Tortoise’ Shoulder Girdle In Space Frame Design Of An Ambulance Body, Sarah A. Matiko

Doctoral Dissertations and Master's Theses

It appears that there is a need for affordable, functional and safe emergency medical support service vehicles in rural Sub-Saharan Africa (SSA). It is inferred that the road conditions have an influence on the availability, durability and affordability of motorized and non-motorized vehicles in rural areas. Also, it is deduced that locally modified bicycle and motorcycle ambulances are not conducive to maternal patients during emergencies. This study investigates the feasibility of modelling an ergonomically and crashworthy patient compartment for road conditions in rural SSA. The patient compartment is modelled by establishing geometrical requirements via a design standard for emergency medical …

An Archival Analysis Of Stall Warning System Effectiveness During Airborne Icing Encounters, John Michael Maris

Doctoral Dissertations and Master's Theses

An archival study was conducted to determine the influence of stall warning system performance on aircrew decision-making outcomes during airborne icing encounters. A Conservative Icing Response Bias (CIRB) model was developed to explain the historical variability in aircrew performance in the face of airframe icing. The model combined Bayes’ Theorem with Signal Detection Theory (SDT) concepts to yield testable predictions that were evaluated using a Binary Logistic Regression (BLR) multivariate technique applied to two archives: the NASA Aviation Safety Reporting System (ASRS) incident database, and the National Transportation Safety Board (NTSB) accident databases, both covering the period January 1, 1988 …

Variable Structure Feedback Control With Application To Spacecraft With Small Thrust Propulsion Systems, Samuel J. Kitchen-Mckinley

Doctoral Dissertations and Master's Theses

Small spacecrafts requiring small propulsion systems are becoming more popular for low Earth orbit. It is important for these research satellites to have accurate guidance and control systems. Small propulsion systems will also be beneficial for multiple small spacecrafts used future exploration expeditions beyond low Earth orbit. These small spacecrafts benefit from the simplicity of low thrust cold gas propulsion systems. Additionally, large spacecrafts using low thrust, high specific impulse propellants for main propulsion systems, such as ion engines, allow longer and more flexible missions, including Earth orbiting spacecraft and interplanetary spacecraft.

In order to extend the life of future …