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Full-Text Articles in Engineering
Flow Induced Vibration In Corrugated Metal Flexhoses, Patrick Tran
Flow Induced Vibration In Corrugated Metal Flexhoses, Patrick Tran
Electronic Theses and Dissertations, 2020-
This study on flow-induced vibration provides valuable insights into the fundamental dynamics of fluid-structure interactions. The findings contribute to the development of predictive models and design guidelines for engineering systems susceptible to flow-induced vibration. By improving our understanding of this phenomenon, engineers can enhance the safety and reliability of various structures subjected to fluid flow, such as pipelines, flexhoses, and bellows. Flowinduced vibration is a phenomenon that occurs when fluid flow interacts with a structure, leading to oscillations and potentially causing mechanical damage. Understanding the underlying mechanisms and predicting the vibration characteristics is crucial for the design and safe operation …
A Study Of The Performance Of Wind Turbines Fitted With Sprayed Liquid Flaps, Alexander Spitzer
A Study Of The Performance Of Wind Turbines Fitted With Sprayed Liquid Flaps, Alexander Spitzer
Electronic Theses and Dissertations, 2020-
Lift generating technologies are often considered a potential solution to increased power generation and reliability within wind turbine design. The Sprayed Liquid Flap (SLF) is a novel active control method that has shown success in providing lift generation on aircraft wings, but its application in the context of rotating flows is unexplored. This research aims to understand the effects of the SLF on a wind turbine and provide a pathway for future exploration of its aerodynamic impacts on rotating flows. Computational Fluid Dynamics with an Euler-Euler multiphase approach is employed to assess the influence of the SLF on a wind …
Trajectory Design Optimization Using Coupled Radial Basis Functions (Crbfs), Kyler Roy
Trajectory Design Optimization Using Coupled Radial Basis Functions (Crbfs), Kyler Roy
Electronic Theses and Dissertations, 2020-
Optimal trajectory design has been extensively studied across multiple disciplines adopting different techniques for implementation and execution. It has been utilized in past space trajectory missions to either optimize the amount of fuel spent or minimize the time of flight to meet mission requirements. Coupled Radial Basis Functions (CRBFs) are a new way to solve these optimal control problems, and this thesis applies CRBFs to spacecraft trajectory optimization design problems. CRBFs are real-valued radial basis functions (RBFs) that utilize a conical spline while also not being affected by the value of the shape parameter. The CRBF approach is applied to …
A Study Of The Influence Of Heat Flux On Aerodynamics In Hypersonic Flow, Kristina Pionessa
A Study Of The Influence Of Heat Flux On Aerodynamics In Hypersonic Flow, Kristina Pionessa
Electronic Theses and Dissertations, 2020-
This study investigates the utilization of computational fluid dynamics (CFD) to simulate aerodynamic heating effects in support of research and design endeavors. The initial investigation demonstrates the effectiveness of a computational approach in analyzing different geometries and flow conditions. Specifically, CFD is employed to analyze the aerodynamics of a blunt cone, double cone, and hypersonic leading edge experiencing a changing heat source across the flow/body boundary. At the stagnation point, maximum thermal loading occurs as previously found; therefore, boundary layer thickness and shock standoff distance is measured at that position to compare the results of each case. Characteristics such as …
A High-Pressure Shock Tube Study Of Hydrogen And Ammonia Addition To Natural Gas For Reduced Carbon Emissions In Power Generation Gas Turbines, Michael Pierro
A High-Pressure Shock Tube Study Of Hydrogen And Ammonia Addition To Natural Gas For Reduced Carbon Emissions In Power Generation Gas Turbines, Michael Pierro
Electronic Theses and Dissertations, 2020-
Ignition delay times from undiluted mixtures of natural gas (NG)/H2/Air and NG/NH3/Air were measured using a high-pressure shock tube at the University of Central Florida. The combustion temperatures were experimentally tested between 1000-1500 K near a constant pressure of 25 bar. Mixtures were kept undiluted to replicate the same chemistry pathways seen in gas turbine combustion chambers. Recorded combustion pressures exceeded 200 bar due to the large energy release, hence why these were performed at the high-pressure shock tube facility. The data is compared to the predictions of the NUIGMech 1.1 mechanism for chemical kinetic model validation and refinement. An …
The Effects Of Microgravity On The Development Of Osteoporosis, Jackson Asiatico
The Effects Of Microgravity On The Development Of Osteoporosis, Jackson Asiatico
Electronic Theses and Dissertations, 2020-
Previous research has identified a potential link between microgravity conditions and the onset of osteoporosis, a connection that stems from altered fluidic pathways crucial in nutrient dispersion and cell stimulation. Specifically, the absence of mechanical loading in space environments reduces fluid shear stress, thereby disrupting the normal flow of interstitial fluid in trabecular bone. This disruption greatly impacts the functionality of osteoblasts and osteoclasts, the vital cells responsible for maintaining healthy bones. The focus of this study aims to explore the impact of microgravity on bone loss in astronauts, establishing the connection between the lack of mechanical loading and the …
The Performance Of A Liquid-Fueled High Pressure Igniter For Scramjets, Gerardo Rodriguez
The Performance Of A Liquid-Fueled High Pressure Igniter For Scramjets, Gerardo Rodriguez
Electronic Theses and Dissertations, 2020-
Ignition systems within scramjet combust ors remain a trending topic of research because of the essential role they play in the engine's operation. An alternative to currently researched ignition systems is investigated in this study with the main goal of u tilizing the same liquid fuel as the mai n combustion chamber for the ignition system itself. In this case, JetA fuel was injected in a liquid jet in crossflow configuration with air to atomize the fuel. To characterize this ignition system, metrics such as combustion chamber pressure rise, pulse frequency, and jet penetration were used to validate possible utilization …
Heat Release And Flame Scale Effects On Turbulence Dynamics In Confined Premixed Flows, Max Fortin
Heat Release And Flame Scale Effects On Turbulence Dynamics In Confined Premixed Flows, Max Fortin
Electronic Theses and Dissertations, 2020-
As industry transitions to a net-zero carbon future, turbulent premixed combustion will remain an integral process for power generating gas turbines and are also desired for aviation engines due to their ability to minimize pollutant emissions. However, accurately predicting the behavior of a turbulent reacting flow field remains a challenge. To better understand the dynamics of premixed reacting flows, this study experimentally investigates the evolution of turbulence in a high-speed bluff-body combustor. The combustor is operated across a range of equivalence ratios from 0.7-1 to quantify the role of heat release and flame scales on the evolution of turbulence as …
Rotorcraft Lander Fixed To A Descending Capsule Backshell, Corey Zucker
Rotorcraft Lander Fixed To A Descending Capsule Backshell, Corey Zucker
Electronic Theses and Dissertations, 2020-
NASA is financing a mission to study the surface of Titan, Saturn's largest moon, to investigate the terrain, chemical compositions, and potential for existent life. This mission is an exciting advancement from Mars Ingenuity, because the quadrotor lander, Dragonfly, will be the first of its kind with four coaxial rotors. Upon entry into Titan, and at near surface atmospheric conditions, Dragonfly will exit a parachute supported backshell that has shed its protective heatshield. The aerodynamics of this state are significant in comprehending the dynamics of the overall system for successful deployment into powered flight. The studies presented here examine the …
Determination Of Damage Initiation Mechanisms In Aerospace Alloys Due To Stress Corrosion Cracking Via In-Situ Microscale Characterization Techniques, Remelisa Esteves
Determination Of Damage Initiation Mechanisms In Aerospace Alloys Due To Stress Corrosion Cracking Via In-Situ Microscale Characterization Techniques, Remelisa Esteves
Electronic Theses and Dissertations, 2020-
Aluminum alloys are used on aerospace vehicles due to their high strength-to-weight ratio, formability and machinability. However, they become vulnerable to stress corrosion cracking (SCC) during their service life. SCC is primarily caused by the material's stress condition, a suitable corrosive environment and material susceptibility. It is also influenced by a mixture of electrochemical, mechanical, and chemical factors. Due to the complexity of SCC, tools with better resolution and sensitivity are needed to better understand the impact and interaction of the contributing factors. A vast amount of research has been done to study SCC behavior, but the scale of characterization …
Characterizing Air Plasma Sprayed Aluminum Oxide Coatings For The Protection Of Structures In Lunar Environments, Perla Latorre Suarez
Characterizing Air Plasma Sprayed Aluminum Oxide Coatings For The Protection Of Structures In Lunar Environments, Perla Latorre Suarez
Electronic Theses and Dissertations, 2020-
Wear-resistant ceramic and ceramic composite coatings are significant to provide durability and support long-duration missions to the moon's surface for rovers, landers, robotic systems, habitats, and many other components. On the Lunar surface, structural components are continuously exposed to lunar dust projectiles that can cause protective coating delamination around the affected area, of protective coatings and this may not be physically visible. Ceramic coatings, composed of alumina, present excellent resistance to different types of wear due to their high strength and hardness as well as the ability to protect structural components from regolith impacts, wear, and abrasive damage. Air Plasma …
The Effect Of Wing Shape And Ground Proximity On Unsteady Fluid Dynamics During The Perching Maneuver., Dibya Raj Adhikari
The Effect Of Wing Shape And Ground Proximity On Unsteady Fluid Dynamics During The Perching Maneuver., Dibya Raj Adhikari
Electronic Theses and Dissertations, 2020-
While landing, birds often perform a perching maneuver, which involves pitching their wings upwards while decelerating to a complete stop. By performing this perching maneuver, the birds can continue generating higher lift and drag force while slowing down, resulting in a smooth landing. The present study is motivated by the perching maneuver and aims to investigate two critical aspects of it. First, we want to explore how the proximity of the ground affects the unsteady forces and the flow field during the perching flight; and second, we want to analyze how a wing sweep influences a perching maneuver. To explore …
An Evaluation Of Thermocouple Reconstruction Techniques, Derek Brauneis
An Evaluation Of Thermocouple Reconstruction Techniques, Derek Brauneis
Electronic Theses and Dissertations, 2020-
Temperature measurements can be difficult to obtain across many different harsh environments such as engine combustion chambers, engine exhaust temperatures, and explosion fireballs. While there are alternate methods to measure fluid temperature such as laser measurements, acoustic measurements, and camera imaging techniques, these methods can often be expensive, difficult to implement, and not able to see within the environment. Thermocouples are popular sensors because they are cheap and easy to implement across a wide range of applications and can measure temperature in areas where other methods cannot reach or see. However, while these sensors are very popular and versatile, they …
The Development Of Computational Models For Melting-Solidification Applications Using The Volume-Of-Fluid Method, Brendon Cavainolo
The Development Of Computational Models For Melting-Solidification Applications Using The Volume-Of-Fluid Method, Brendon Cavainolo
Electronic Theses and Dissertations, 2020-
Fluids-related issues in the Aerospace industry are often multiphase in scope. Numerical modeling, such as computational fluid dynamics, is used to describe these problems, as they are difficult or impossible to describe analytically. This research uses computational fluid dynamics to describe multiphase problems related to melting-solidification and particle impingement. Firstly, a numerical model was established that uses the Volume-of-Fluid method to resolve a melting/solidifying particle. This model was verified against experiments and simplified analytical models, and a mesh independence study was done to ensure the results were independent of the mesh sizing. Next, the model was applied to two separate …
Design Considerations And Imaging Setup For Liquid Fuel Droplet Detonation Wave Experiments, Nicolas Berube
Design Considerations And Imaging Setup For Liquid Fuel Droplet Detonation Wave Experiments, Nicolas Berube
Electronic Theses and Dissertations, 2020-
Initial results, design considerations, and experimental validation of a new detonation tube are presented to further improve detonation wave interaction research. The new structure consists of four independent portions: the deflagration to detonation initiation section, transition expansion section, operating test section, and dump section. The initiation, transition, and test sections are designed to operate within a temperature limit of 150°C and a maximum detonation pressure of 100 bar. The test section is comprised of interchangeable 155 cm stainless steel 316 plates assembled to create a 10x10 cm square hollow structure, sealed with longitudinal O-rings between plates and lateral O-rings between …
Detonability Of A Rotating Detonation Combustor Seeded With Carbon/Hydrocarbon Particles At Fringe Operating Conditions, Matthew Hopwood
Detonability Of A Rotating Detonation Combustor Seeded With Carbon/Hydrocarbon Particles At Fringe Operating Conditions, Matthew Hopwood
Electronic Theses and Dissertations, 2020-
The Rotating Detonation Combustor (RDC) has, in recent years, been a subject of great interest in the pressure-gain combustion research community. Researchers have been investigating the RDC as a potential improvement over current combustors in today's turbomachinery-based power generation systems. With the theoretical efficiency boost that detonations provide over deflagrating combustors, RDCs have the promise to be a next step in fuel/cost savings in the power generation industry. One mode of research to push an RDCs capabilities is the potential use of combustible carbon/hydrocarbon solid particles in addition to liquid or gaseous fuels. These particles are a source of high …