Aerospace Engineering Commons^™

Adaptive, Neural And Robust Control Of Wing-Rock And Aeroelastic System, Prince Ghorawat

UNLV Theses, Dissertations, Professional Papers, and Capstones

Modern aircraft exhibit wing-rock phenomenon and aeroelastic instability. Wingrock (roll single degree of freedom motion) and aeroelastic systems' (two degrees of freedom) behavior are described by complex nonlinear differential equations. The nonlinearities in the dynamics of these systems give rise to limit cycle oscillations beyond critical speed of aircraft. The onset of wing-rock and aeroelastic instability limits the performance of aircraft and can even lead to catastrophic consequences. Therefore, control of wing-rock motion and stabilization of aeroelastic systems are important. In the past, several studies have been made and experimental and analytical results have been obtained to explain the wing-rock …

Modeling And Simulation Of Radiation From Electronic Transitions In Hypersonic Atmospheric Reentry Flow, Curtis Scholz

Doctoral Dissertations and Master's Theses

A capability for higher accuracy heat transfer modeling in CFD for hypersonic re-entry flows, via inclusion of thermal radiation, is sought. With temperatures reaching tens of thousands of degrees, radiation is known to be significant to chemical reaction rates and thermal boundary layer development, hence surface heat transfer and thermal ablation both to the heat shield and the backshell region of re-entry vehicles. Two current NASA solicitations seek such an improved capability relative to the Mars and Earth entry problems, as uncertainty typically leads to overdesign and excess weight. The present research develops a first physics-based “building block,” which computes …

Supersonic Retro-Propulsion Computational Fluid Dynamics Analysis Applied To Future Mars Mission, Margarita Nataly Brandt

Doctoral Dissertations and Master's Theses

Supersonic Retro-Propulsion is one of the most promising emerging technologies being considered by NASA for use in future Mars missions. This new form of Entry Descent Landing has the potential to help increase the allowable payload mass currently constraining many science instruments and operations. Computational Fluid Dynamics was used to show the feasibility of supersonic retro - propulsion in Mars atmospheric conditions. The results presented show the SRP will be able to perform satisfactory using the same conditions that the Curiosity Rover was exposed to during its landing sequence. The plume expansion was analyzed for various cases, moving from free …

Attitude Determination & Control System Design And Implementation For A 6u Cubesat Proximity Operations Mission, Francisco J. Franquiz

Doctoral Dissertations and Master's Theses

The purpose of this work is to discuss the attitude determination and control system (ADCS) design process and implementation for a 12 kg, 6U (36.6 cm x 23.9 cm x 27.97 cm) CubeSat class nano-satellite. The design is based on the requirements and capabilities of the Application for Resident Space Object Proximity Analysis and IMAging (ARAPAIMA) proximity operations mission. The satellite is equipped with a cold gas propulsion system capable of exerting 2.5 mN m torques in both directions about each body axis. The attitude sensors include an angular rate gyro and star tracker (STR), supplemented by the payload optical …

Phased Array Beamsteering In Composite Laminates For Guided Wave Structural Health Monitoring, Peter Osterc

Doctoral Dissertations and Master's Theses

In this study a guided wave phased array beamsteering approach is applied to composite laminates. Current beamsteering algorithms derived for isotropic materials assume omnidirectional wave propagation. Due to inherent anisotropy in composites, guided wave propagation varies with direction and wavefronts no longer have perfect circular shapes.

By examining slowness, velocity and wave curves, as well as amplitude variation with direction for a given composite laminate, the wavefront from a single source can be described as a function of the angle of propagation and distance from origin. Using this approach, a more general delay and sum beamforming algorithm for composite laminates …

Surface Structure And Its Effect On Reducing Drag, Ragini Ramachandran

Doctoral Dissertations and Master's Theses

A miniature subsonic open return wind tunnel was designed and fabricated to measure drag on small test models at low Reynolds numbers. The wind tunnel featured a sensitive strain gauge type load cell. The average drag coefficient of sphere and cube test models were used to validate the miniature wind tunnel, and the values obtained were consistent with published results over the range of Reynolds numbers tested. These initial results gave confidence that the tunnel could be used to study the effects of surface finish on the drag of various models. Several fabrics with differing ribbed surface structures, including a …

Techno-Economic Feasibility And Life Cycle Assessment Of Dairy Effluent To Biofuel Via Hydrothermal Liquefaction, Hailey M. Summers

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Delactosed whey permeate (delac) is a low valued by-product in the dairy industry with 90 million tons annually disposed of worldwide. Upgrading delac to bioproducts, specifically biofuel, has been demonstrated at laboratory scale through yeast fermentation. However, the large-scale environmental impact and economic feasibility of this process is yet to be quantified. Further research, focused on evaluating the sustainability, scalability and economic feasibility of the fermentation pathway, directs research and development to move the technology towards commercialization. The enclosed research incorporates biological experimentation with engineering systems modeling to evaluate the large-scale environmental impacts and economic feasibility of generating bioproducts from …

Methods Of Processing Kenaf Chopped Strand Mats For Manufacturing Test Specimens And Composite Structures, Joshua W. Heil

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Every year in the United States, 10 to 11 million vehicles reach the end of their life cycle. Nearly all of these go to a recycling facility. After the recycling process is complete an average of 25% of each vehicle, by weight, goes to waste. This demonstrates the need to use natural fibers in parts that could be recycled, like parts that can be made from kenaf. There are many reasons to consider using natural/bio-fiber composites (bio-composites). These reasons include human health and environmental factors as well as advantages that natural fibers have over fiberglass, such as: lower costs and …

High Regression Rate Hybrid Rocket Fuel Grains With Helical Port Structures, Sean D. Walker

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Hybrid Rockets are popular in the aerospace industry due to their storage safety, simplicity, and controllability during rocket motor burn. However, they produce fuel regression rates typically 25% lower than solid fuel motors of the same thrust level. These lowered regression rates produce unacceptably high oxidizer-to-fuel (O/F) ratios that produce a potential for motor instability, nozzle erosion, and reduced motor duty cycles. To achieve O/F ratios that produce acceptable combustion charactersitics, traditional cylindrical fuel ports are fabricated with very long length-to-diameter ratios to increase the total burning area. these high aspect ratios produce further reduced fuel regression rate and trust …

Parameterized Least-Squares Attitude History Estimation And Magnetic Field Observations Of The Auroral Spatial Structures Probe, Ryan J. Martineau

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

As charged particles from the Sun enter the Earth’s atmosphere and create the aurora borealis (Northern lights) and aurora australis (Southern lights), energy is transferred to the atmosphere. In order to better understand the energy transfer processes, the Auroral Spatial Structures Probe rocket was launched to make measurements in the active aurora. Several payloads were deployed by the rocket, each with sensors to measure the magnetic field and the electric field so that the way they change over time and in different positions could be observed. The measurements require accurate knowledge of the spacecraft orientation, and to that end this …

Computational Fluid Dynamics Simulations Of Oscillating Wings And Comparison To Lifting-Line Theory, Megan Keddington

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Computational fluid dynamics (CFD) analysis was performed in order to compare the solutions of oscillating wings with Prandtl’s lifting-line theory. Quasi-steady and steady-periodic simulations were completed using the CFD software Star-CCM+. Quasi-steady simulations were completed for both twodimensional and three-dimensional setups. The steady-periodic simulations were only performed using a three-dimensional setup. The simulations were performed for nine separate frequencies in a pure plunging setup. An additional four simulations were then completed using a setup of combined pitching and plunging at four separate frequencies. Results from the CFD simulations were compared to the quasi-steady lifting-line solution in the form of the …

Direct Electrical Arc Ignition Of Hybrid Rocket Motors, Michael I. Judson Jr.

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Hybrid rockets motors provide distinct safety advantages when compared to traditional liquid or solid propellant systems, due to the inherent stability and relative inertness of the propellants prior to established combustion. As a result of this inherent propellant stability, hybrid motors have historically proven difficult to ignite. State of the art hybrid igniter designs continue to require solid or liquid reactants distinct from the main propellants. These ignition methods however, reintroduce to the hybrid propulsion system the safety and complexity disadvantages associated with traditional liquid or solid propellants. The results of this study demonstrate the feasibility of a novel direct …

A Neural Network Approach To Fault Detection In Spacecraft Attitude Determination And Control Systems, John N. Schreiner

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

CubeSats are employed in a variety of missions as scientific platforms, low-cost technology demonstrators, and in the future, they will conduct service missions as part of larger satellite constellations. CubeSat ADCS designers today are being tasked with designing to ever increasing accuracy requirements. The ability to hold those requirements rests with the attitude control system being robust enough and able to sufficiently respond to changes in the control environment. The need for greater control autonomy is then evident in the need for these systems to be able to react independently to changes in the system dynamics and to identify and …

Mapping Regional Inundation With Spaceborne L-Band Sar, Bruce Chapman, Kyle Macdonald, Masanobu Shimada, Ake Rosenqvist, Ronny Schroeder, Laura Hess

Publications and Research

Shortly after the launch of ALOS PALSAR L-band SAR by the Japan Space Exploration Agency (JAXA), a program to develop an Earth Science Data Record (ESDR) for inundated wetlands was funded by NASA. Using established methodologies, extensive multi-temporal L-band ALOS ScanSAR data acquired bi-monthly by the PALSAR instrument onboard ALOS were used to classify the inundation state for South America for delivery as a component of this Inundated Wetlands ESDR (IW-ESDR) and in collaboration with JAXA’s ALOS Kyoto and Carbon Initiative science programme. We describe these methodologies and the final classification of the inundation state, then compared this with results …

Investigations Of Synthetic Fuels: S8 And Sasol Ipk To Determine The Possibility Of Alternate Fuels In The Aerospace Industry, Scott M. Dyke

GS4 Student Scholars Symposium

Investigations of Synthetic Fuels: S8 and Sasol IPK to Determine the Possibility of Operation as Alternate Fuels in the Aerospace Industry

Name: Scott Dyke

Co-Authors: Martin Muinos, Julia Heimberger, Dr. Valentin Soloiu,

An ever-growing society that becomes more and more dependent on a finite energy source will eventually exceed its supply. Fossil fuel quantities are continuously decreasing and new solutions are needed. According to the United States Department of Transportation, over 10 billion gallons of airline fuels have been consumed in each of the past 15 years with some years over 13 billion gallons. In the meantime, fuel costs have …

Design And Analysis Of A Labview And Arduino-Based Automatic Solar Tracking System, Caiwen Ding

Morehead State Theses and Dissertations

A Thesis Presented to the Faculty of the College of Science and Technology Morehead State University in Partial Fulfillment of the requirements for the Degree Master of Science by Caiwen Ding April 24, 2015

Simulation Of Complex Ionic Liquid Ionization Process, Forrest Grady Kidd Iii

Research and Creative Activities Poster Day

The future of satellites will require dual-mode propulsion to obtain dynamic orbits. One set of propellants capable of dual-mode propulsion are ionic liquids. These energy-dense liquids have similar thrust characteristics to SOTA monopropellants and low vapor pressures making them safer to handle. That low vapor pressure makes ionization more difficult as it requires the propellant to be in a gaseous state. This requires experiments to determine how to efficently vaporize and ionize this propellant. Computational modelling is needed to guide these experiments and to develop simulations that can extrapolate the data to more complex geometries.

Unstandard Cubesat/Pocketqube/Tubesat Deployers, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created by Professor Bob Twiggs titled "Unstandard CubeSat/PocketQube/TubeSat Deployers" from April 23, 2015.

A Radio Frequency Beacon Receiver For Detection Of Ionospheric Scintillation, Tim Neilsen, Don Thompson, Steve Higley, Todd Parris, Jake Gunther

Space Dynamics Laboratory Publications

Radio Frequency Beacon Receiver

• What is RFBR?
• A low-cost, ground-based beacon receiver
• Producing ionospheric parameters:
• Total Electron Content (TEC) 
• Amplitude scintillation (S4)
• Phase scintillation (σ_φ)
• Using COTS RF hardware and Software Defined Radios (SDRs) 
• Advanced algorithms and software

Flying The X-15 And Space Shuttle, Joe H. Engle

ERAU Prescott Aviation History Program

Hear what it was like for Joe H. Engle, USAF/ANG, Ret. to fly both the X-15 and the Space Shuttle. In 1965 Capt. Engle flew the X-15 to 280,600 feet, to become the youngest pilot to qualify as an astronaut and would go on to fly it 15 more times. Selected for NASA space missions, he flew the Space Shuttle “Enterprise” off the top of a modified 747 on glide flight tests. He commanded the orbital test flight of “Columbia” and became the first and only pilot to manually fly an aerospace vehicle from Mach 25 to landing. A remarkable …

Cdtx: Cool Drop Test Experiment, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint presentation created by Professor Bob Twiggs titled "CDTX: Cool Drop Test Experiment" from April 7, 2015.

High Powered Composite Payload Fairing Rocket For Deployable Robotics, Markus R. Murdy

Research Horizons Day Posters

No abstract provided.

Comparison Of Radiation Dosage For Human Piloted Mars Missions Using Chemical, Nuclear Thermal, And Fusion Propulsion Systems, Steven Doyle

Research Horizons Day Posters

No abstract provided.

Flow Induced Vibration On Piezoelectric Structures: Prediction, Experiment And Applications, Felix Ewere

Research Horizons Day Posters

No abstract provided.

Particulate Matter Emission Estimates From Agricultural Spring Tillage Operations Using Lidar And Inverse Modeling, Kori D. Moore, Michael D. Wojcik, Randal S. Martin, Christian C. Marchant, Derek S. Jones, William J. Bradford, Gail E. Bingham, Richard L. Pfeiffer, John H. Prueger, Jerry L. Hatfield

Space Dynamics Laboratory Publications

Particulate matter (PM) emissions from a typical spring agricultural tillage sequence and a strip-till conservation tillage sequence in California’s San Joaquin Valley were estimated to calculate the emissions control efficiency (η) of the strip-till conservation management practice (CMP). Filter-based PM samplers, PM-calibrated optical particle counters (OPCs), and a PM-calibrated light detection and ranging (lidar) system were used to monitored upwind and downwind PM concentrations. Emission rates were estimated through inverse modeling coupled with the filter and OPC measurements and through applying a mass balance to the PM concentrations derived from lidar data. Sampling irregularities and errors prevented the estimation of …

Slip Length Crossover On A Graphene Surface, Zhi Liang, Pawel Keblinski

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Using Equilibrium and Non-Equilibrium Molecular Dynamics Simulations, We Study the Flow of Argon Fluid above the Critical Temperature in a Planar Nanochannel Delimited by Graphene Walls. We Observe that, as a Function of Pressure, the Slip Length First Decreases Due to the Decreasing Mean Free Path of Gas Molecules, Reaches the Minimum Value When the Pressure is Close to the Critical Pressure, and Then Increases with Further Increase in Pressure. We Demonstrate that the Slip Length Increase at High Pressures is Due to the Fact that the Viscosity of Fluid Increases Much Faster with Pressure Than the Friction Coefficient between …

Morris Leroy Spearman

Virginia Journal of Science

Obituary for Morris Leroy Spearman

Delamination Of C/Pekk I-Beam Using Virtual Crack Closure Technique And Cohesive Zone Method, Greeshma Ramakrishna

Open Access Theses

A damage study is conducted on a carbon epoxy/PEKK (poly-ether-ketone-ketone) thermoplastic composite I-Beam, with a pre crack of 100 mm modeled between the top flange and the filler (butt joint between filler and web). This project is in collaboration with Fokker Aerostructures, Netherlands and is part of the Thermoplastic Primary Aircraft Structure innovation program (TAPAS). The C/PEKK I-Beam is modeled after a section of the Gulfstream G650 aircraft's centre beam, which was previously a carbon fiber/epoxy hat-stiffened skin construction. The objective of the thesis is to identify if the crack propagates in the I-Beam within the load range that act …

An Experimental Study On The Effects Of Blade Row Interactions On Aerodynamic Loss Mechanisms In A Multistage Compressor, Natalie Rochelle Smith

Open Access Dissertations

While the gas turbine engine has existed for nearly 80 years, much of the complex aerodynamics which governs compressor performance is still not well understood. The unsteady flow field consists of periodic blade row interactions from the wakes and potential fields of each blade and vane. Vane clocking is the relative circumferential indexing of adjacent vane rows with the same vane count, and it is one method to change blade row interactions. Though the potential of performance benefits with vane clocking is known, the driving flow physics have yet to be identified. ^ This research examines the effects of blade …

The Panther: 2015 Aiaa Design Build Fly, Bryce Milnes, Chris Crawford

Publications

The ERAU Prescott chapter of AIAA participated in the 2015 AIAA Design Build Fly competition at Raytheon Missile Systems in Tucson from April 10-12. A remote controlled aircraft meeting and exceeding all competition performance requirements was designed and fabricated by the 30+ students of the team. Additionally, a 60 page report was submitted detailing the project starting from initial considerations and advancing through flight test verification of aircraft capabilities. The success of this project was enabled by the E-Prize and SGA funding received to support our efforts throughout the year. The lessons learned regarding management and planning, engineering design approaches, …