Aerospace Engineering Commons^™

The Effects Of Supersonic Reacting Flow Over A Wedge, Taylor R. Brown

Honors Undergraduate Theses

There is a growing need for a fundamental understanding of how detonations are formed and sustained as propulsion technology advances toward the use of detonation-based engines. The deflagration-to-detonation transition (DDT) phenomenon is studied to better understand both the fundamentals of detonation physics and the conditions surrounding how detonations are formed and sustained. This research aims to study the effects of a wedge on DDT and detonation formation. A hydrogen-air mixture is pumped into a chamber and ignited by a spark plug. Turbulence-driven flame acceleration is induced by turbulators in the chamber through which the flame propagates. The flame then flows …

Thrust Augmentation Of Rotating Detonation Rocket Engines, Alexander G. Rodriguez

Honors Undergraduate Theses

This thesis aims to perform a detailed analysis on a 5th Order Polynomial Nozzle, verifying its effectiveness in improving the thrust performance of a Rotating Detonation Rocket Engine. Rotating detonation engines are a promising engine type that uses detonations as a means of combustion rather than traditional conflagration. Through this method, these engines can produce significant amounts of energy while burning less fuel in the process. However, exhaust flow instabilities and swirl limit the engine's potential for use as a means of propulsion. The 5th Order Polynomial Nozzle was previously demonstrated to reduce and control this swirl; however, analysis was …

Vibrations Of Rotationally Periodic Structures: A Metric For Mistuning Characterization And Vibration Localization, Andres Rodriguez

Electronic Theses and Dissertations, 2020-2023

Blisk components are an integral part of jet engines and power generation systems. Composed of a single monolithic structure, integral blisks combine the blade-and-disk portion of primary components such as the fan, compressor stage, or turbine stage. This design modification increases the aerodynamic performance while decreasing the cost and eliminating time of assembly. However, these benefits come with the loss of blade-disk connection interfaces, which greatly reduces the structure's damping and its ability to attenuate unwanted structural vibrations. Blisk dynamics are impacted by mistuning, which is a disruption of the periodic symmetry of otherwise identical bladed sections. This disruption degrades …

Generic Behavior Framework Of Sx And Ds Nickel-Base Superalloys With Applications To Constitutive And Life Prediction Modeling, Firat Irmak

Electronic Theses and Dissertations, 2020-2023

Selection of materials to be used for components experiencing extreme conditions is a critical process in the design phase. Nickel-base superalloys have been frequently used for hot gas path components in the turbomachinery industry. These components are required to withstand both fatigue and creep at extreme temperatures during their service time. In general, the extreme temperature materials mostly embody polycrystalline, directionally solidified, and single crystal superalloys. It is essential for design engineers to predict accurate damage behavior and lifespan for these components to prevent catastrophic failures. This dissertation presents a new framework to represent mechanical behavior of Nickel-base superalloys under …

The State Of The Art Of Information Integration In Space Applications, Zhuming Bi, K. L. Yung, Andrew W.H. Ip., Yuk Ming Tang, Chris W.J. Zhang, Li Da Xu

Information Technology & Decision Sciences Faculty Publications

This paper aims to present a comprehensive survey on information integration (II) in space informatics. With an ever-increasing scale and dynamics of complex space systems, II has become essential in dealing with the complexity, changes, dynamics, and uncertainties of space systems. The applications of space II (SII) require addressing some distinctive functional requirements (FRs) of heterogeneity, networking, communication, security, latency, and resilience; while limited works are available to examine recent advances of SII thoroughly. This survey helps to gain the understanding of the state of the art of SII in sense that (1) technical drivers for SII are discussed and …

Drone Cage Design And Implementation To Enable Small Drone Architecture Testing, Marco Fagetti, Emily M. Suh

Undergraduate Student Works

Geometric mechanics is a dynamical formalism that allows for simultaneous treatment of rotational and translational motion without the drawbacks of attitude parameterization sets. While geometric mechanics is well suited to deal with full six degree-of-freedom motion or significant position-attitude coupling, this formalism has yet to be extensively applied to hardware systems. The broader research goals of this work aim to prove the practical viability of this theoretical framework by applying it to a class of Crazyflie drones, which are frequently used to assess Guidance, Navigation, and Control schemes. To efficiently achieve these goals, a reliable, collapsible drone cage is required …

Evaluation Of Onboard Detect-And-Avoid System For Suas Bvlos Operations, Jon M. Loffi, Samuel M. Vance, Jamey Jacob, Luke Spaulding, Jared C. Dunlap

International Journal of Aviation, Aeronautics, and Aerospace

No abstract provided.

Effect Of The Extended Rigid Flapping Trailing Edge Fringe On An S833 Airfoil, Hongtao Yu, Zifeng Yang

Mechanical and Materials Engineering Faculty Publications

A 2D numerical simulation was conducted to investigate the effect of an extended rigid trailing edge fringe with a flapping motion on the S833 airfoil and its wake flow field, as an analogy of an owl’s wing. This study aims to characterize the influence of the extended flapping fringe on the aerodynamic performance and the wake flow characteristics downstream of the airfoil. The length (Le) and flapping frequencies (fe) of the fringe are the key parameters that dominate the impact on the airfoil and the flow field, given that the oscillation angular amplitude is fixed at 5◦. The simulation results …

Influence Of Nonlinear Multiaxial Matrix Viscoelasticity On Piezoresistivity Of Carbon Nanotube Polymer Composites, Wolfgang Klimm

Electronic Theses and Dissertations, 2020-2023

Nanocomposites are prominent candidates to extend the capabilities in areas of established fiber reinforced composites. Carbon nanotubes (CNT) with their outstanding mechanical, electrical, and thermal properties are of particular interest. Especially polymers profit from the addition of CNTs, and can be rendered significantly stiffer, stronger, and even electrically conductive. The resulting electrical conductance is deformation-sensitive, known as piezoresistivity, and is utilized in strain sensing applications. However, the polymer matrix introduces time- and temperature-dependency into the mechanical behavior, known as viscoelasticity, and thus affects the relationship between deformation and electrical conductivity over time. Although piezoresistivity and polymer viscoelasticity have been studied …

Sensitivity Of Combustion Liner Contour To Sand Ingestion Clogging, Nelson Padilla

Electronic Theses and Dissertations, 2020-2023

This currently presented work is an evaluation of the characteristics of different cooling hole geometries to particulate ingestion clogging. Experimentation was conducted using a premixed bluff body flame combustor facility to generate high temperature combustor flow conditions. Sand ingestion along the cooling path of the combustion liner was reproduced using an air-assisted seeder providing consistent sand ingestion. Mass flow rate of cooling air was controlled using a sonic orifice downstream of a pressure regulator so that the mass flow rate of the air and sand mixture is independent of the clogging state. Pressure data upstream of a small section of …

Design And Mechanical Characterization Of Functionally Graded Sandwich Beams Fabricated Via Additive Manufacturing, Timothy Grondin

Electronic Theses and Dissertations, 2020-2023

Lightweight aerospace structures have been sought after since humans took flight in 1903, making major strides in NASA's pursuit of the moon with the development of sandwich panel composites. Sandwich structures typically consist of two stiff phases (i.e., face sheets) separated by a lightweight phase (i.e., core), which are stacked together through adhesive layers. Such a structural arrangement provides a high stiffness-to-weight ratio and is often used in applications where weight saving is critical. Functionally Graded Materials (FGMs), refer to multifunctional materials, which contain a spatial variation of composition and/or microstructure for the specific purpose of altering thermal and structural …

On Liquid Rotating Detonation Rocket Engines Characterization And Performance, Vidhan Malik

Electronic Theses and Dissertations, 2020-2023

The current research investigates a next-generation method of combustion called detonations for propulsive applications which has support from the Combustion Services Branch at the Air Force Research Laboratory (AFRL) of the Rocket Propulsion Division. The overall initiative seeks to explore the viability of detonation-based systems to augment or replace current rocket propulsion methods in the coming five years. The present work progresses this vision by providing proof of a liquid RP-2 based Rotating Detonation Rocket Engine (RDRE) as well as the fundamentals associated with the physics involved to further the understanding of the phenomenon and its potential uses. Phase one …

A Unified Tool For Adaptive Collocation Techniques Applied To Solving Optimal Control Problems, Bethany Kelly

Electronic Theses and Dissertations, 2020-2023

In this work, a user-friendly MATLAB tool is introduced to solve nonlinear optimal control problems by applying collocation techniques using Coupled Radial Basis Functions (CRBFs). CRBFs are a new class of Radial Basis Functions combined with a conical spline r^5, which provides the advantage of insensitivity to the shape parameter while maintaining accuracy and robustness. To solve optimal control problems, software tools are often employed to implement numerical methods and apply advanced techniques to solving differential equations. Although several commercial software tools exist for solving optimal control problems, such as ICLOCS2, GPOPS, and DIDO, there are no options available that …

The Breakup Of Rp-2 Liquid Fuel Droplets In A Detonation Field, Daniel Dyson

Electronic Theses and Dissertations, 2020-2023

Experimentally obtained droplet breakup patterns are presented for RP-2 liquid fuel droplets in the environment behind a detonation wave. To the best of our knowledge, this data is the first of its kind to examine the fundamental interactions between detonation waves and an individual fuel droplet. The experiments presented here are expected to support the ongoing effort of creating accurate models of droplet breakup in a variety of environments, which in turn will lead to enhanced predictions of rotating detonation engine performance, improved safety considerations for facilities operating in hazardous conditions, and new knowledge in energetics, hypersonics, and explosion dynamics …

Integrating Experimental Parameter Space For Granular Flow Within Polygon Tumblers, Michaela Mcmahon

Graduate Research Theses & Dissertations

Granular flows are complex phenomena bridging both fluid and solid mechanics and observed frequently in the natural world. The transitional dynamics of acceleration from solid body motion to rapid flow can affect many aspects including volume flow rates and mixing behaviors. In order to study the combination of both variables together within polygon-shaped tumblers, control systems are necessary with a corresponding user interface. This thesis reports an interface for changing variable inputs to the system. Predictions of rotation rates with corresponding interfaces with hardware connections are described. Results of image analysis verify output performance that incorporates the following variable changes: …

Experimental Analysis Of Flowing Layer Characteristics In Equilateral Triangular Tumblers For Quasi-2d Macro-Particle Flow, Jason Quinn Ostenburg

Graduate Research Theses & Dissertations

Rotating tumblers are used in a wide variety of industrial applications from mixing anddeburring to flow regulation and storage. Almost all model tumblers previously analyzed, both theoretically and experimentally, had circular cross sections that produced consistent flowing layer dimensions and steady state flow. In contrast, tumblers with triangular cross sections produced unsteady flow as a direct result of the dynamic dimensions of the flowing surface. Although unsteady, the flow produced in triangular tumblers is periodic every 120◦ of rotation after an initial mixing period. The mechanisms by which the flow characteristics vary as a triangular tumbler rotates and the number …

Design, Development, And Testing Of Near-Optimal Satellite Attitude Control Strategies, Giovanni Lavezzi

Electronic Theses and Dissertations

Advances in space technology and interest toward remote sensing mission have grown in the recent years, requiring the attitude control subsystems of observation satellites to increase their performances in terms of pointing accuracy and on-board implementability. Moreover, an increased interest in small satellite missions and the recent technological developments related to the CubeSats standard have drastically reduced the cost of producing and flying a satellite mission. In this context, the proposed research aims to improve the state of the art for satellite attitude control methodologies by proposing a near-optimal attitude control strategy, simulated in a high-fidelity environment. Two strategies are …

Microscale Transverse Compression Modeling: A Comparative Study Of The Analytical Mac/Gmc Methods To Experimental Results, Emily Zeitunian

Dissertations, Master's Theses and Master's Reports

Composite materials require a multi-scale approach to fully understand its behavior. At the micro level, material behavior analysis is conducted most often using numerical or analytical approaches. These models, however, require validation from experimental data to ensure material predictions are accurate. This study compares a semi-analytical micromechanical analysis tool, MAC/GMC, to experimental results of in-situ microscale transverse compression testing conducted at AFRL facilities. Effective properties, stress-strain curves, stress and strain fields, and damage predictions are compared with experimental outputs. Both generalized method of cells (GMC) and high-fidelity generalized method of cells (HFGMC) theories implemented within MAC/GMC show results that agree …

Broadband Investigation Of The Pyrolysis Of Propane Using A Mir Optical Parametric Oscillator, Robert Greene

Electronic Theses and Dissertations, 2020-2023

The chemistry of propane continues to play a pivotal role in today's power production technologies. As reliance on natural gas expands as greener cleaner fuels are sought throughout the world, especially as countries are attempting to transition away from traditional coal and crude-oil fired plants towards solar, wind, and hydro-electric sources. Natural gas, often seen as a bridge fuel between these two competing ends, has been in the recent past and for the foreseeable future will continue to play an important role in the energy sector. Among the components of natural gas, propane plays a key role in the chemistry …

Shape Parameter & Nodal Distribution Insensitive Radial Basis Functions For Nonlinear Optimal Control Problems, Ahmed Elsadek Ahmed Elshafee Seleit

Electronic Theses and Dissertations, 2020-2023

Computational optimal control relies mainly on pseudospectral methods. The use of Chebyshev and Legendre polynomials is ubiquitous in the literature. This family of methods has good accuracy characteristics but constraints the nodal distribution to a certain grid that is denser at the boundaries. In this work, a set of novel Coupled Radial Basis Functions (CRBFs) is introduced as an approximation means for the nonlinear optimal control problem. CRBFs are real-valued Radial Basis Functions (RBFs) augmented with a conical spline. They do not require a specific nodal distribution. A plethora of research articles were published on the optimization of the shape …

Model-Based Systems Engineering For A Small-Lift Launch Facility, Walter Mcgee Taraila, Sharanabasaweshwara Asundi

Mechanical & Aerospace Engineering Faculty Publications

A study of model‐based systems engineering (MBSE) applied to a small‐lift launch facility is presented. The research uses Systems Modeling Language (SysML) products and functional diagrams to document the ground systems on a launch pad servicing a small class payload (0–2 tons). With the projected growth in launch cadence of small‐lift rockets in the coming decade, there is a need to design increasingly complex launch systems with greater efficiency. The potential improvements in project communication, quality, and productivity are explored by developing a model following the ISO/IEC 15288 technical process framework and the International Council on Systems Engineering (INCOSE) Object‐Oriented …

Recent Analytic Development Of The Dynamic Q-Tensor Theory For Nematic Liquid Crystals, Xiang Xu

Mathematics & Statistics Faculty Publications

Liquid crystals are a typical type of soft matter that are intermediate between conventional crystalline solids and isotropic fluids. The nematic phase is the simplest liquid crystal phase, and has been studied the most in the mathematical community. There are various continuum models to describe liquid crystals of nematic type, and Q-tensor theory is one among them. The aim of this paper is to give a brief review of recent PDE results regarding the Q-tensor theory in dynamic configurations.

High-Pressure Kinetic Interactions Between Co And H2 During Syngas Catalytic Combustion On Pdo, Ran Sui, John Mantzaras, Rolf Bombach, Meysam Khatoonabadi

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The catalytic combustion of H2/CO/O2/N2 mixtures over PdO was investigated at pressures 3 to 10 bar, H2:CO volumetric ratios 1:5 to 3:1, and global equivalence ratios ψ = 0.13 and 0.23. The catalyst surface temperatures were controlled to 540-690 K, a range especially important for hybrid hetero-/homogeneous combustion approaches with large gas turbines at idle or part-load operation and for microreactors with recuperative small-scale turbines. In situ Raman measurements determined the major gas-phase species concentrations over the catalyst boundary layers in a channel-flow reactor, thermocouples monitored the surface temperatures, and surface characterization identified the catalyst oxidation state (PdO) and surface …

Jointly-Learnt Networks For Future Action Anticipation Via Self-Knowledge Distillation And Cycle Consistency, Md Moniruzzaman, Zhaozheng Yin, Zhihai He, Ming-Chuan Leu, Ruwen Qin

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Future action anticipation aims to infer future actions from the observation of a small set of past video frames. In this paper, we propose a novel Jointly learnt Action Anticipation Network (J-AAN) via Self-Knowledge Distillation (Self-KD) and cycle consistency for future action anticipation. In contrast to the current state-of-the-art methods which anticipate the future actions either directly or recursively, our proposed J-AAN anticipates the future actions jointly in both direct and recursive ways. However, when dealing with future action anticipation, one important challenge to address is the future's uncertainty since multiple action sequences may come from or be followed by …

Guiding A Human Follower With Interaction Forces: Implications On Physical Human-Robot Interaction, George L. Holmes, Keyri Moreno Bonnett, Amy Costa, Devin Michael Burns, Yun Seong Song

Psychological Science Faculty Research & Creative Works

This work challenges the common assumption in physical human-robot interaction (pHRI) that the movement intention of a human user can be simply modeled with dynamic equations relating forces to movements, regardless of the user. Studies in physical human-human interaction (pHHI) suggest that interaction forces carry sophisticated information that reveals motor skills and roles in the partnership and even promotes adaptation and motor learning. In this view, simple force-displacement equations often used in pHRI studies may not be sufficient. To test this, this work measured and analyzed the interaction forces (F) between two humans as the leader guided the blindfolded follower …

Developing Reactive Distributed Aerial Robotics Platforms For Real-Time Contaminant Mapping, Joshua Ashley

Theses and Dissertations--Electrical and Computer Engineering

The focus of this research is to design a sensor data aggregation system and centralized sensor-driven trajectory planning algorithm for fixed-wing aircraft to optimally assist atmospheric simulators in mapping the local environment in real-time. The proposed application of this work is to be used in the event of a hazardous contaminant leak into the atmosphere as a fleet of sensing unmanned aerial vehicles (UAVs) could provide valuable information for evacuation measures. The data aggregation system was designed using a state-of-the-art networking protocol and radio with DigiMesh and a process/data management system in the ROS2 DDS. This system was tested to …

Editorial For The Special Issue On Micromachines For Non-Newtonian Microfluidics, Lanju Mei, Shizhi Qian

Mechanical & Aerospace Engineering Faculty Publications

In lieu of an abstract, this is an excerpt from the first page.

Microfluidics has seen a remarkable growth over the past few decades, with its extensive applications in engineering, medicine, biology, chemistry, etc [...]

On The Implementation And Further Validation Of A Time Domain Boundary Element Method Broadband Impedance Boundary Condition, Fang Q. Hu, Douglas M. Nark

Mathematics & Statistics Faculty Publications

A time domain boundary integral equation with Burton-Miller reformulation is presented for acoustic scattering by surfaces with liners in a uniform mean flow. The Ingard-Myers impedance boundary condition is implemented using a broadband multipole impedance model and converted into time domain differential equations to augment the boundary integral equation. The coupled integral-differential equations are solved numerically by a March-On-in-Time (MOT) scheme. While the Ingard-Myers condition is known to support Kelvin-Helmholtz instability due to its use of a vortex sheet interface between the flow and the liner surface, it is found that by neglecting a second derivative term in the current …

Investigating Ground Interactions Of A Rotocraft Landing Vehicle On Titan, Adam Rozman

Honors Undergraduate Theses

The exploration of celestial bodies has recently advanced from rovers to rotorcraft. This includes the recent flights of Mars Ingenuity and the upcoming Dragonfly mission to explore the terrain of Saturn’s moon Titan as part of NASA’s New Frontiers Program. Flight-based landers can travel quickly to sites kilometers apart and land in complex terrain. Although cruise conditions for these rotorcrafts are well understood, studies are necessary to understand take-off and landing. In ground effect conditions, a rotor wake impinges and reflects off the ground, creating changes in aerodynamics such as increased lift. Additionally, operating over loose surfaces, the rotors can …

Investigation Of Pitching And Plunging Motions On A Tandem Wing Configuration, Riley M. Capiro

Honors Undergraduate Theses

From the beginning of the history of flight, inspiration has been drawn from nature. Evolution has spent millions of years optimizing creatures that rely on flight as their means of locomotion. Today, aerial vehicles are very different to those from the time of the Wright brothers. One kind of vehicle that stands to benefit in mimicking nature is the drone, particularly smaller drones. Commonly used today by militaries, industry and civilians, drones are increasingly affordable while also decreasing in size thanks to advancements in electronics and manufacturing methods. The purpose of this thesis is to investigate how pitching and rolling …