Kentucky Re-Entry Universal Payload System (Krups): Hypersonic Re-Entry Flight,
2022
University of Kentucky
Kentucky Re-Entry Universal Payload System (Krups): Hypersonic Re-Entry Flight, John Daniel Schmidt
Theses and Dissertations--Mechanical and Aerospace Engineering
The Kentucky Re-entry Universal Payload System (KRUPS) is a small capsule designed as a technology testbed for re-entry experiments. For its first incarnation, KRUPS has been designed to test Thermal Protection Systems (TPS) and instruments in re-entry flights. Because of the unique environment a vehicle undergoes during re-entry, there is a high-demand for experimental data from re-entry experiments. KRUPS has been developed at the University of Kentucky (UK) over the past seven years to meet this demand. After completing sub-orbital campaigns, the first KRUPS hypersonic re-entry mission was attempted. The mission involved building three 11-inch diameter capsules each outfitted with …
Numerical And Scaling Study On Application Of Inkjet Technology To Automotive Coating,
2022
University of Kentucky
Numerical And Scaling Study On Application Of Inkjet Technology To Automotive Coating, Masoud Arabghahestani Dr.
Theses and Dissertations--Mechanical and Aerospace Engineering
A thorough literature review identified lack of precision control over quality of droplets generated by the currently available industrial sprayers and a growing need for higher quality droplets in the coating industry. Particularly, lack of knowledge and understanding in continuous inkjets (CIJ) and drop-on-demand (DOD) technologies is identified as significant. Motivated by these needs, this dissertation is dedicated to computational fluid dynamics (CFD) and scaling studies to improve existing inkjet technologies and develop new designs of efficient coating with single and/or multiple piezoelectric sensors to produce on-demand droplets. This dissertation study aims at developing a new DOD type coating technology, …
In-Situ Characterization Of Burr Formation In Finish Machining Of Inconel 718,
2022
University of Kentucky
In-Situ Characterization Of Burr Formation In Finish Machining Of Inconel 718, Hamzah M. Zannoun
Theses and Dissertations--Mechanical and Aerospace Engineering
One of the undesirable byproducts that occur during the machining process is the development of burrs, which are defined as rough excess material that forms around the geometric discontinuities of a part. Burrs are especially problematic because they have negative impacts across the triple bottom line: economic, environmental, societal. For one, they are expensive to remove because the deburring process is entirely manual and requires skill. Further, burr material is typically discarded which is adding to the already mounting waste generated from machining such as in coolant and chip disposal. Lastly, there are many societal implications, such as operator injury …
Experimental Investigation Of Roughness And Blowing Effects Over Ablator-Like Surfaces,
2022
University of Kentucky
Experimental Investigation Of Roughness And Blowing Effects Over Ablator-Like Surfaces, Colby Borchetta
Theses and Dissertations--Mechanical and Aerospace Engineering
Two separate experiments using PIV were carried out to investigate the effects of
roughness and blowing over surfaces geometrically similar to ablation materials used for atmospheric re-entry. The first, water tunnel experiments, employed a dimpled surface similar to AVCOAT, while the second set was completed in a wind tunnel with a material similar to PICA. For the first set, the flow with blowing becomes destabilized, and more disorganized. The blowing disrupts the relatively simple vorticity shedding process and significantly modifies momentum transport via interaction of detached structures. Flow structure and their modifications were examined with a sPOD analysis. The focus …
Formation Control With Collision Avoidance For Fixed-Wing Unmanned Air Vehicles With Speed Constraints,
2022
University of Kentucky
Formation Control With Collision Avoidance For Fixed-Wing Unmanned Air Vehicles With Speed Constraints, Christopher Heintz
Theses and Dissertations--Mechanical and Aerospace Engineering
Advances in the miniaturization of powerful electronic components and motors, the democratization of global navigation satellite systems (GNSS), and improvements in the performance, safety, and cost in lithium batteries has led to the proliferation of small and relatively inexpensive unmanned aerial vehicles (UAVs). Many of these UAVs are of the multi-rotor design, however, fixed-wing designs are often more efficient than rotary-wing aircraft, leading to a reduction in the power required for a UAV of a given mass to stay airborne. Autonomous cooperation between multiple UAVs would enable them to complete objectives that would be difficult or impossible for a single …
Quantification Of The Aerodynamic Drivers Of A Deployable Propeller,
2022
University of Central Florida
Quantification Of The Aerodynamic Drivers Of A Deployable Propeller, David Malyszek
Electronic Theses and Dissertations, 2020-2023
With the use deployable drones becoming more common research into their improvement is necessary. Deployable drones that are launched from tubes have size limits on the diameter of the propeller during launch and storage. The purpose of this research is to develop deployable propeller blades for practical uses, such as tube launched propeller driven drones and easier to transport wind turbine blades. A deployable propeller will allow for the utilization of larger propellers when a large non-deployable blade isn't an option. Because deployable propellers need to fold, the deployable propeller blades were designed to be hollow and with a slit …
A Study Of Microgravity On Fluid Transport Through Porous Structures In Microfluidic Devices,
2022
University of Central Florida
A Study Of Microgravity On Fluid Transport Through Porous Structures In Microfluidic Devices, Sylvain Le Henaff
Electronic Theses and Dissertations, 2020-2023
The objective of this study is to refine the understanding of micro-fluidics subject to micro-gravity in an attempt to support future space exploration efforts. A combination of experimental and numerical approaches were utilized to build a validated assessment approach. A quasi-pore geometry, inspired by CT scans of rat bones, was used in lieu of human bone structures. A quasi-1D assessment of the conservation of momentum was used to identify the dominant forces acting on the fluid at the operating length-scales. The dominant forces were surface tension, gravity, and shear stress. Experiments were conducted to visualize the flow moving through the …
Interactions Of Aerosol Droplets With Ventilated Airflows In The Context Of Airborne Pathogen Transmission,
2022
University of Central Florida
Interactions Of Aerosol Droplets With Ventilated Airflows In The Context Of Airborne Pathogen Transmission, Steven Schroeder
Electronic Theses and Dissertations, 2020-2023
This multidisciplinary study provides a comprehensive visualization of airborne aerosols and droplets coming into contact with a crossflow of moving air utilizing both experimental particle measuring methods and multiphase computational fluids dynamics (CFD). The aim of this research is to provide a Eulerian visualization of how ventilation can alter the position and density of an aerosol cloud, with the goal of applying this information to our understanding of social distancing ranges within outdoor settings and ventilated rooms. The results indicate that even minor perpendicular crossflows across the trajectory of an aerosol cloud can greatly reduce both the linear displacement and …
Effects Of Wheel Rotation On Long-Period Wake Dynamics Of The Drivaer Fastback Model,
2022
Missouri Unviersity of Science and Technology
Effects Of Wheel Rotation On Long-Period Wake Dynamics Of The Drivaer Fastback Model, Matthew Aultman, Rodrigo Auza-Gutierrez, Kevin Disotell, Lian Duan
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Lattice Boltzmann method (LBM) simulations were performed to capture the long-period dynamics within the wake of a realistic DrivAer fastback model with stationary and rotating wheels. The simulations showed that the wake developed as a low-pressure torus regardless of whether the wheels were rotating. This torus shrank in size on the base in the case of rotating wheels, leading to a reduction in the low-pressure footprint on the base, and consequently a 7% decrease in the total vehicle drag in comparison to the stationary wheels case. Furthermore, the lateral vortex shedding experienced a long-period switching associated with the bi-stability in …
Juggling A Devil-Stick: Hybrid Orbit Stabilization Using The Impulse Controlled Poincaré Map,
2022
Missouri University of Science and Technology
Juggling A Devil-Stick: Hybrid Orbit Stabilization Using The Impulse Controlled Poincaré Map, Nilay Kant, Ranjan Mukherjee
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The control design for juggling a devil-stick between two symmetric configurations is proposed. Impulsive forces are applied to the devil-stick at the two configurations; and impulse of the force and its point of application are modeled as the control inputs. The dynamics of the devil-stick is described by a single return Poincaré map, and it is shown that the control objective of juggling can be achieved by stabilizing a hybrid orbit. The impulse controlled Poincaré map (ICPM) approach, recently proposed for stabilization of continuous-time orbits of underactuated systems, is extended to achieve asymptotic stabilization of the hybrid orbit. The applicability …
Additive Manufacturing Of Continuous Carbon Fiber-Reinforced Sic Ceramic Composite With Multiple Fiber Bundles By An Extrusion-Based Technique,
2022
Missouri University of Science and Technology
Additive Manufacturing Of Continuous Carbon Fiber-Reinforced Sic Ceramic Composite With Multiple Fiber Bundles By An Extrusion-Based Technique, Ruoyu Chen, Adam Bratten, Joshua Rittenhouse, Ming-Chuan Leu, Haiming Wen
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Due to the high cost, complex preparation process and difficulty in structural design, the traditional methods for carbon fiber reinforced SiC ceramic composite preparation have great limitations. This paper presents a technique for the additive manufacturing multiple continuous carbon fiber bundle-reinforced SiC ceramic composite with core-shell structure using an extrusion-based technique. A conventional nozzle system was modified to print simultaneously a water based SiC paste with continuous carbon fibers. Different levels of binder contents were investigated to optimize the stickiness, viscosity, thixotropy and viscoelasticity of the paste. After sintering, SiC whiskers were generated on the surface of fiber, which is …
Passive Intermodulation Under Different Spring Contact Conditions,
2022
Missouri University of Science and Technology
Passive Intermodulation Under Different Spring Contact Conditions, Shengxuan Xia, Emmanuel Olugbade, Yuchu He, Yansheng Wang, Hanfeng Wang, Krishna Rao, Marco Poort, Haicheng Zhou, Warren Lee, Nicholas Mcdonnell, Jonghyun Park, Chulsoon Hwang
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Modularized designs have been widely used in today's consumer electronic devices and flexible RF springs are used for electrical connections between the modules. In the meantime, aluminum alloy material becomes a common chassis option. It is well known that the oxidized chassis surface introduces a certain level of nonlinearity when contacted by the springs, as known as passive intermodulation (PIM). PIM is one of the well-known root causes of the RF desensitization (desense). This paper is focused on investigating the relationship between PIM and contact conditions of the springs, especially contact area. The PIM level behavior is explained mathematically by …
Fuel-Rich Hetero-/Homogeneous Combustion Of C3h8/O2/N2 Mixtures Over Rhodium,
2022
Missouri University of Science and Technology
Fuel-Rich Hetero-/Homogeneous Combustion Of C3h8/O2/N2 Mixtures Over Rhodium, John Mantzaras, Ran Sui, Rolf Bombach
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The catalytic (heterogeneous) and gas-phase (homogeneous) combustion of C3H8/O2/N2 mixtures over rhodium was investigated experimentally and numerically at 5 bar and at fuel-rich equivalence ratios π = 2.0-3.5 relevant to propane Catalytic Partial Oxidation (CPO). In situ spatially-resolved Raman measurements of major gas-phase species concentrations and Planar Laser Induced Fluorescence (PLIF) of formaldehyde were applied in an optically accessible channel-flow reactor to monitor the catalytic and gas-phase processes, respectively, while accompanying 2D simulations were carried out with detailed hetero-/homogeneous chemical reaction mechanisms. Due to the high gas-phase reactivity of propane, homogeneous chemistry could not be ignored over most of the …
Regulation Of Dendrite-Free Li Plating Via Lithiophilic Sites On Lithium-Alloy Surface,
2022
Missouri University of Science and Technology
Regulation Of Dendrite-Free Li Plating Via Lithiophilic Sites On Lithium-Alloy Surface, Yufang He, Mengyun Zhang, Aiping Wang, Bo Zhang, Hiep Pham, Qiao Hu, Li Sheng, Hong Xu, Li Wang, Jonghyun Park, Xiangming He
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Lithium (Li) deposition behavior plays an important role in dendrite formation and the subsequent performance of lithium metal batteries. This work reveals the impact of the lithiophilic sites of lithium-alloy on the Li plating process via the first-principles calculations. We find that the Li deposition mechanisms on the Li metal and Li22Sn5 surface are different due to the lithiophilic sites. We first propose that Li plating on the Li metal surface goes through the "adsorption-reduction-desorption-heterogeneous nucleation-cluster drop "process, while it undergoes the "adsorption-reduction-growth "process on the Li22Sn5 surface. The lower adsorption energy contributes to the easy adsorption of Li on …
Direct Numerical Simulation Of Acoustic Disturbances In A Hypersonic Two-Dimensional Nozzle Configuration,
2022
Missouri University of Science and Technology
Direct Numerical Simulation Of Acoustic Disturbances In A Hypersonic Two-Dimensional Nozzle Configuration, Nathaniel Hildebrand, Meelan M. Choudhari, Cole P. Deegan, Junji Huang, Lian Duan
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Direct numerical simulations (DNS) are performed to study acoustic radiation in a quasi-two-dimensional nozzle with two independents spatially evolving turbulent boundary layers with an edge Mach number of 6. The emphasis of this work is to compare the radiated pressure fluctuations in a geometrically confined environment with those radiated from a single wall in an unconfined setting. The boundary-layer profile of the rms pressure fluctuation scaled by the mean shear stress at the wall is found to be in good agreement with prior flat-plate calculations at similar conditions. However, the normalized rms pressure fluctuation within the freestream p region is …
Neural Network Attitude Control System Design For The Wallops Arc-Second Pointer,
2022
Missouri University of Science and Technology
Neural Network Attitude Control System Design For The Wallops Arc-Second Pointer, Pavel Galchenko, Henry J. Pernicka
Mechanical and Aerospace Engineering Faculty Research & Creative Works
No abstract provided.
Nanobubble Capillary Force Between Parallel Plates,
2022
Missouri University of Science and Technology
Nanobubble Capillary Force Between Parallel Plates, Eric Bird, Zhi Liang
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The Aggregation of Fine or Ultrafine Particles in Liquid Due to the Nanobubble (NB) Bridging Capillary Force is a Key Process for Many Industrial Applications. the Magnitude and Direction of the NB Capillary Force (NBCF) Are Directly Affected by the Geometry of the NB Gas Bridge between Two Adjoining Particles. Although the NBCF Can Be Accurately Measured using Experimental Techniques, It is Very Challenging to Monitor the Images of a NB Capillary Bridge in Nanoscale Spatial Resolution in NBCF Measuring Experiments. as a Result, the Capillary Force Model that Predicts the Dependence of the NBCF on the Geometry of the …
Feature Learning For Optimal Control With B-Spline Representations,
2022
Missouri University of Science and Technology
Feature Learning For Optimal Control With B-Spline Representations, Vinay Kenny, Sixiong You, Chaoying Pei, Ran Dai
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The paper develops a feature learning-based method to solve optimal control problems using B-splines to approximate the optimal solutions. The feature learning-based optimal control method can quickly generate near-optimal trajectories for general optimal control problems subject to system dynamics and constraints. The steps in the proposed method are as follows: Firstly, by representing the state and control variables with B-spline functions, the optimal control problem is converted into an approximate nonlinear programming (NLP) problem, where parameters of the B-splines are identified as features of the optimal solution. Secondly, for a specific problem with designated inputs, a dataset of the optimal …
Calorimetric Measurements Of Lunar Regolith Simulant And Water. An Experimental Study Correlating Weight Percent Water And Temperature Change Through Periods Of Phase Change.,
2022
Michigan Technological University
Calorimetric Measurements Of Lunar Regolith Simulant And Water. An Experimental Study Correlating Weight Percent Water And Temperature Change Through Periods Of Phase Change., George B. Johnson
Dissertations, Master's Theses and Master's Reports
Permanently Shaded Regions (PSRs) are cold traps located around the lunar south pole that have been confirmed to contain possible interesting quantities or volatiles such as H2O, CO2, SO2, CH4, and others. [1] The identification of these volatiles on the lunar surface was a critical step in the development of NASA’s strategic goals for scientific discoveries, sustained space travel and exploration, and re-establishing a human presence on the moon. These volatiles are vital to the future of operating in and exploring space. The LCROSS impact revealed the existence of these resources in PSRs but more information is needed about the …
On The Use Of High-Frequency Surface Wave Oceanographic Research Radars As Bistatic Single-Frequency Oblique Ionospheric Sounders,
2022
Old Dominion University
On The Use Of High-Frequency Surface Wave Oceanographic Research Radars As Bistatic Single-Frequency Oblique Ionospheric Sounders, Stephen R. Kaeppler, Ethan S. Miller, Daniel Cole, Teresa Updyke
CCPO Publications
We demonstrate that bistatic reception of high-frequency oceanographic radars can be used as single-frequency oblique ionospheric sounders. We develop methods that are agnostic of the software-defined radio system to estimate the group range from the bistatic observations. The group range observations are used to estimate the virtual height and equivalent vertical frequency at the midpoint of the oblique propagation path. Uncertainty estimates of the virtual height and equivalent vertical frequency are presented. We apply this analysis to observations collected from two experiments run at two locations in different years, but utilizing similar software-defined radio data collection systems. In the first …
