Aerospace Engineering Commons^™

J-85 Model Development For Performance Optimization, Austin Childers

Theses and Dissertations

Larsen Motorsports is a local jet racing facility in Melbourne, Florida. Larsen Motorsports is a key partner with Florida Tech. Larsen Motorsports has a highly skilled manufacturing team along with a robust manufacturing capability. Through their team’s many years of racing Larsen Motorsports has tuned and developed engineering for both the J-60 and J-85 jet engines. These modifications vary from small design changes to production of components to entire system redesigns. One of the most extensive redesigns their team has developed is the afterburner section of the General Electric J-85 jet engine. Their team has designed and tuned the entire …

A Quantitative Analysis Of The Robinson R44 Performance Characteristics, Jon Carroll Holzman

Theses and Dissertations

The Robinson R44 is the most prolific civil helicopter in the world with over 6,000 delivered to customers since 1992. Approved for normal category flight by the FAA through 14 CFR Parts 21 and 27, the accompanying Pilot's Operating Handbook includes all performance material required under the same. Practical planning materials, such as cruise charts and accompanying fuel flow rates for various operational weights and density altitudes, however, are absent. This leaves a large gap in flight planning resources needed for an airframe which is currently being used in a broad range of demanding civil capacities to include offshore oil …

Accumulation Of Polar Vorticity On Giant Planets: Towards A Three-Dimensional Theory, Shawn R. Brueshaber

Dissertations

My research investigates the polar atmospheric dynamics of the giant planets: Jupiter and Saturn (gas giants), and Uranus and Neptune (ice giants). I conduct my research modifying and applying the Explicit Planetary Isentropic Coordinate global circulation code to model the polar regions of the four giant planets.

The motivation behind my research is to uncover the reason why giant planet polar atmospheric dynamics differ. Jupiter features multiple circumpolar cyclones arranged in geometrical configurations, whereas Saturn features a single pole-centered cyclone. Uranus and Neptune also appear to have single pole-centered cyclones, albeit, larger than those on Saturn. …

Investigating Newly Discovered Oscillation Modes In Magnetically Shielded Hall Effect Thrusters Utilizing High Speed Diagnostics, Matthew Joseph Baird

Dissertations

Magnetically shielded Hall effect thrusters (MSHETs) are a variant of Hall effect thrusters (HET) that provide the favorable thrust-to-power ratio and high specific impulse of traditional stationary plasma type (STP) HETs but with an extremely long lifetime. MSHETs exhibit unique discharge plasma oscillations compared to traditional unshielded HETs. In this study, measurements of plasma oscillations in the state-of-the-art 12.5 kW Hall Effect Rocket with Magnetic Shielding (HERMeS) were obtained at various discharge voltages while holding other operation parameters constant. Data were collected using high-speed imaging, voltage, current, and plasma probes. The thruster exhibits two dominant oscillation modes within the discharge …

Dynamic Effects Of Inertial Particles On The Wake Recovery Of A Model Wind Turbine, Sarah E. Smith

Dissertations and Theses

Impacting particles such as rain, dust, and other debris can have devastating structural effects on wind turbines, but little is known about the interaction of such debris within turbine wakes. This study aims to characterize behavior of inertial particles within the turbulent wake of a wind turbine and relative effects on wake recovery. Here a model wind turbine is subjected to varied two-phase inflow conditions, with wind as the carrier fluid (Re_λ = 49 - 88) and polydisperse water droplets (26 to 45µm in diameter) at varied concentrations (Φ_v=0.24 x 10^-5 - 1.3 …

Droplet Ejections During Wet Lab Operations Aboard Spacecraft, Caleb Cushman Turner

Dissertations and Theses

The breakup and rupture of liquid bridges, thin films, bubbles, droplets, rivulets, and jets can produce satellite droplets that are subsequently ejected into their surrounding environment. For example, when any solid object is withdrawn from a liquid bath, the formation of an ever-thinning columnar liquid bridge eventually ruptures along the axis of the bridge. When rupture occurs under typical pipetting conditions the dynamics governing the rupture almost always produce at a minimum a satellite droplet. When these droplets occur they are often too small and too fast to be observed by the human eye. In a terrestrial environment they are …

Coupled Inflow And Structural Dynamics Of Rotors With Time Delays And Adjoint Variables, Cory Andrew Seidel

McKelvey School of Engineering Graduate Student Theses & Dissertations

In this work, the finite-state models of Morillo-Duffy and Fei (including the Adjoint Theorem) are expanded to calculate the coupled inflow and rotor dynamics of a multi-rotor systems. Because the Adjoint Theorem involves coupling of rotor and inflow states with adjoint rotor states (including pure time delays in both types of variables), the resultant coupled dynamics experiences characteristics heretofore not studied in a dynamic system. It is the purpose of this work to study these new and interesting dynamic behaviors that can occur in the physically meaningful context of a coaxial rotor. The work is also interested in how this …

Improving Thermal Conduction Across Cathode/Electrolyte Interfaces In Solid-State Lithium-Ion Batteries By Hierarchical Hydrogen-Bond Network, Jinlong He, Lin Zhang, Ling Liu

Mechanical and Aerospace Engineering Student Publications and Presentations

Effective thermal management is an important issue to ensure safety and performance of lithium-ion batteries. Fast heat removal is highly desired but has been obstructed by the high thermal resistance across cathode/electrolyte interface. In this study, self-assembled monolayers (SAMs) are used as the vibrational mediator to tune interfacial thermal conductance between an electrode, lithium cobalt oxide (LCO), and a solid state electrolyte, polyethylene oxide (PEO). Embedded at the LCO/PEO interface, SAMs are specially designed to form hierarchical hydrogen-bond (H-bond) network with PEO. Molecular dynamics simulations demonstrate that all SAM-decorated interfaces show enhanced thermal conductance and dominated by H-bonds types. The …

Secondary Uses Of Ballutes After Aerocapture, Josiah Shelton

Master's Theses

Aerocapture is a method for spacecraft orbital insertion that is currently being assessed for use in interplanetary missions. This method would use a low periapsis hyperbolic entry orbit to induce drag allowing the spacecraft to slow down without the use of a propulsion system. This is accomplished by using a ballute (balloon parachute), which is released after the appropriate change in velocity necessary to achieve the desired planetary orbit. Once released, the ballute could deploy a secondary mission vehicle. A MATLAB simulation was run to understand the environment a secondary payload would undergo, such as heating and deceleration, as well …

Distributed Adaptive State Estimation And Tracking Scheme For Nonlinear Systems Using Active Passive Sensor Networks, Akhilesh Raj, S. Jagannathan, Tansel Yucelen

Electrical and Computer Engineering Faculty Research & Creative Works

This paper proposes a novel adaptive neural network (NN) based distributed state estimation scheme for a heterogeneous sensor network (HSN), to estimate the state vector of an unknown nonlinear process/target by using sensed output when the target input remains unknown. The active nodes in the HSN can sense the target output based on the detection range. By using a connected graph, the active nodes will communicate their estimated state vector from their adaptive NN observer to other passive nodes in the neighborhood that cannot sense the target, so that they can estimate the target state vector. Next, a subset of …

Improving Mode Ii Fracture Toughness Of Secondary Bonded Joints Using Laser Patterning Of Adherends, A. Wagih, R. Tao, A. Yudhanto, G. Lubineau

Mechanical and Aerospace Engineering Faculty Research & Creative Works

We improve mode II fracture toughness of secondary bonded joints based on the laser treatment of adherend surfaces. We applied CO₂ Laser treatment to adherend surface alternatively with low and high energy, resulting in a repeated pattern of rough and smooth surfaces. We used ENF test to characterize mode II fracture toughness, GII, of the bonded CFRP substrates. The results demonstrated that our proposed pattern arrested the crack propagation and triggered new damage mechanisms, such as adhesive cracking, adhesive failure and crack migration to the other interface. These additional mechanisms, some of them were non-local in nature, resulted in …

How The Spatial Correlation In Adhesion Properties Influences The Performance Of Secondary Bonding Of Laminated Composites, Xiaole Li, Ran Tao, Arief Yudhanto, Gilles Lubineau

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Spatial heterogeneity of adhesion properties is known to result in bridging during debonding of secondary bonded composite joints. The ligaments that bridge both substrates have crack-arrest features and thus significantly enhance the fracture resistance of joints. We have investigated the effect of randomly distributed adhesion properties between the adhesive layer and each composite substrate in previous works; however, the spatial correlation of adhesion heterogeneity within or between the substrates and how it effects the failure of secondary bonded composites is still poorly understood. In this current work, we assume that the spatial heterogeneity of adhesion follows a log-normal distribution. The …

Piezoresistive Hybrid Nanocomposites For Strain And Damage Sensing: Experimental And Numerical Analysis, Audrey Jean-Miche Gbaguidi

Doctoral Dissertations and Master's Theses

Carbon nanomaterials such as carbon nanotubes (CNTs) and graphite nanoplatelets (GNPs) demonstrate remarkable electrical and mechanical properties, which suggest promising structural and functional applications as fillers for polymer nanocomposites.

The piezoresistive behavior of these nanocomposites makes them ideal for sensing applications. Besides, hybrid nanocomposites with multiple fillers like carbon nanotubes (CNTs) and graphite nanoplatelets (GNPs) are known to exhibit improved electrical and mechanical performance when compared to mono-filler composites.

To comprehensively understand the mechanisms of electrical percolation, conductivity, and piezoresistivity in hybrid nanocomposites, the author develops a two-dimensional (2D) and a three-dimensional (3D) computational Monte Carlo percolation network models for …

Three-Dimensional, Vision-Based Proportional Navigation For Uav Collision Avoidance, Guanhong Gao

Doctoral Dissertations and Master's Theses

As the number of potential applications for Unmanned Aerial Vehicles (UAVs) keeps rising steadily, the chances that these devices will operate in close proximity to static or dynamic obstacles also increases. Therefore, collision avoidance is an important challenge to overcome for Unmanned Aerial Vehicle operations. Electro-optical devices have several advantages such as light weight, low cost, low algorithm requirements with respect to computational power and possibly night vision capabilities. Therefore, vision-based Unmanned Aerial Vehicle collision avoidance has received considerable attention. Although much progress has been made in collision avoidance systems (CAS), most approaches are focused on two-dimensional environments. In order …

An Open Source, Autonomous, Vision-Based Algorithm For Hazard Detection And Avoidance For Celestial Body Landing, Daniel Posada

Doctoral Dissertations and Master's Theses

Planetary exploration is one of the main goals that humankind has established as a must for space exploration in order to be prepared for colonizing new places and provide scientific data for a better understanding of the formation of our solar system. In order to provide a safe approach, several safety measures must be undertaken to guarantee not only the success of the mission but also the safety of the crew. One of these safety measures is the Autonomous Hazard, Detection, and Avoidance (HDA) sub-system for celestial body landers that will enable different spacecraft to complete solar system exploration. The …

Contributions To The Understanding Of Ship Airwakes Using Advanced Flow Diagnostic Techniques, Dhuree Seth

Doctoral Dissertations and Master's Theses

The objective of this research was to better characterize the complex, three dimensional, unsteady aerodynamic flows produced by the superstructure of a ship, which is referred to as an airwake. This problem is relevant and important because the turbulent airwake significantly and adversely affects the ability for rotorcraft to operate safely from the decks of Navy ships. To this end, a series of wind tunnel measurements were performed on the SFS2 simplified frigate shape, which has a flight deck at its stern. The measurements were performed with and without a simulated atmospheric boundary layer (ABL), which included the aerodynamic scaling …

Optimization Of Spacecraft Formations About Lagrange Points For The Next Generation Space Weather Prediction Mission, Roberto Cuéllar Rangel

Doctoral Dissertations and Master's Theses

This thesis’s work serves as proof of concept for the Next Generation Space Weather Prediction Mission, a multi-spacecraft mission at various libration points whose objective is to forecast Space Weather hazards with a 12day warning time. This thesis deals with the design and control of orbits of spacecraft formations at different libration points. The systems studied are SunEarth, SunVenus, SunMercury, and SunMars. The orbit design and formation keeping control of the spacecraft are solved simultaneously using an optimization software called DIDO. Initial conditions are obtained through two different strategies. The first one, by placing the spacecraft in a tetrahedral formation …

Python Implementation Of Batch Least-Squares Filter For Satellite Orbit Determination, Austin Ogle

Doctoral Dissertations and Master's Theses

Accurate orbit determination techniques are fundamental to the maintenance and execution of any ongoing space-based mission. This project serves as a guide and demonstration of a batch sequential least-squares filter for Earth-orbiting satellites using exclusively open-source technologies. The target audience for this project was an academic institution aiming to keep track of an irregularly documented satellite. The observation function mimics a telescope, accepting right ascension and declination as measured values.

State propagation was handled using the Poliastro library. This package boasts FORTRANlevel speed by utilizing the DOPRI8 integrator, explicitly calling FORTRAN code. Matrix inversion was solved using the SciPy banded …

Limitations Of Initial Orbit Determination Methods For Low Earth Orbit Cubesats With Short Arc Orbital Passes, James P. Johnson

Master's Theses

This thesis will focus on the performance of angles only initial orbit determi- nation (IOD) methods on observational data of low Earth orbit (LEO) CubeSats. Using data obtained by Lockheed Martin’s Space Object Tracking (SpOT) facil- ity, four methods: Gauss, Double-R, Gooding and Assumed Circular, will use different amounts of orbital arc to determine which methods perform the best in the short arc regime of less than 10 degrees of orbital arc. Once the best method for estimating the orbit is determined, there will be analysis on whether these IOD methods are accurate enough to predict a secondary observation session. …

Power-Over-Tether Uas Leveraged For Nearly-Indefinite Meteorological Data Acquisition, Daniel Rico, Carrick Detweiler, Francisco Muñoz-Arriola

School of Computing: Dissertations, Theses, and Student Research

Use of unmanned aerial systems (UASs) in agriculture has risen in the past decade. These systems are key to modernizing agriculture. UASs collect and elucidate data previously difficult to obtain and used to help increase agricultural efficiency and production. Typical commercial off-the-shelf (COTS) UASs are limited by small payloads and short flight times. Such limits inhibit their ability to provide abundant data at multiple spatiotemporal scales. In this paper, we describe the design and construction of the tethered aircraft unmanned system (TAUS), which is a novel power-over-tether UAS leveraging the physical presence of the tether to launch multiple sensors along …