Engineering Commons^™

Overview Of Ablation Test-Cases, Alexandre Martin, Jean Lachaud, Tom Van Eekelen, Ioana Cozmuta, Michael Wright, Nagi N. Mansour, Daniele Bianchi

Ablation Workshop

No abstract provided.

Microscale Modeling Of Ablative Thermal Protection System Materials, Eric Stern, Graham Candler, Tom Schwartzentruber, Ioannis Nompelis, Michael Barnhardt

Ablation Workshop

No abstract provided.

Material Response Characterization Of New-Class Ablators In View Of Numerical Model Calibration, Bernd Helber, Alessandro Turchi, T. E. Magin

Ablation Workshop

No abstract provided.

Uncertainty Analysis Of Carbon Ablation In The Vki Plasmatron, Alessandro Turchi, P. M. Congedo, Bernd Helber, T. E. Magin

Ablation Workshop

No abstract provided.

Investigation Of Surface Radiation In Earth Re-Entry Flows With Graphite Ablation, Christopher Alba

Ablation Workshop

No abstract provided.

Surface Effects And Phenomena On Ablative Materials, Alexandre Martin

Ablation Workshop

No abstract provided.

Ablamod: Advanced Ablation Characterization And Modelling European Project Description, Gregory Pinaud, A. Guelhan

Ablation Workshop

No abstract provided.

Overview Of Stmd’S Investments In Advanced Entry, Descent And Landing (Edl), Michael Wright

Ablation Workshop

No abstract provided.

Spacecraft Thermal Design, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs on "Spacecraft Thermal Design" from April 7, 2014.

Power Storage & Control, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs on "Power Storage & Storage" on April 3, 2014.

Multi-Injector Modeling Of Transverse Combustion Instability Experiments, Kevin "James " Shipley

Open Access Theses

Concurrent simulations and experiments are used to study combustion instabilities in a multiple injector element combustion chamber. The experiments employ a linear array of seven coaxial injector elements positioned atop a rectangular chamber. Different levels of instability are driven in the combustor by varying the operating and geometry parameters of the outer driving injector elements located near the chamber end-walls. The objectives of the study are to apply a reduced three-injector model to generate a computational test bed for the evaluation of injector response to transverse instability, to apply a full seven-injector model to investigate the inter-element coupling between injectors …

Experimental Investigation Of A Forced Response Condition In A Multistage Compressor, William Louis Murray

Open Access Theses

The objective of this research is twofold. Firstly, the design, development, and construction of a test facility for a Honeywell APU-style centrifugal compressor was implemented, as well as the design and construction of an inlet flow experiment. Secondly, the aeromechanical response of an embedded stage in the Purdue 3-Stage axial research compressor was analyzed through a suite of different measurement techniques in the fulfillment of the end of the GUIde IV Consortium contract. ^ The purpose of the first phase of Honeywell work was to comprehensively measure the flow field of an APU-style centrifugal compressor inlet through the use of …

Unsteady Forces On A Spherical Particle Accelerating Or Decelerating In An Initially Stagnant Fluid, Yashas Mudlapur Phaneesh Keshav

Open Access Theses

Flows with particles play an important role in a number of engineering applications. These include trajectories of droplets in sprays in fuel-injected-reciprocating-piston and gas-turbine engines, erosion of materials due to particle impact on a surface, and deposition of materials on surfaces by impinging droplets or particles that could solidify or bond on impact. For these applications, it is important to understand the forces that act on the particles so that their trajectories could be predicted.

Considerable work has been done on understanding the forces acting on spherical particles, where the Reynolds numbers (Rep ) based on the particle …

Investigating Surface Performance Trade-Offs Of Unimpeded Taxiways, Tiffany T. Le

Open Access Theses

Optimizing usage of unimpeded taxiways is a near-term operational change to mitigate emission impact on aviation and increase efficiency at airports. An unimpeded taxiway is a path for an aircraft to taxi around an active runway. Unimpeded taxiways provide benefits such as increased departure throughput, increased safety, reduced surface congestion, more efficient taxi-in procedures, and thereby also yield environmental benefits. The goals of this work are to investigate the use of current taxiways, examine surface performance and fuel burn trade-offs, and to develop a decision-support model based on potential fuel savings of unimpeded taxiways. This study analyzes unimpeded taxiway use …

Detecting Air Traffic Controller Interventions In Recorded Air Transportation System Data, Yul Kwon

Open Access Theses

In this study, I propose a systematic method of detecting aircraft deviation due to air traffic controller (ATC) intervention. The aircraft deviations associated with ATC interventions are detected using a heuristic algorithm developed from analyzing the actual positions of an aircraft to its filed flight plan when the aircraft trajectories were identified as having an encounter in a loss-of-separation incident. An actual (closed-loop) flight trajectory of the Cleveland Air Route Traffic Control Center (ZOB ARTCC) was collected from the FlightAware database. This was compared with the corresponding planned (open-loop) trajectory dataset generated by the Microsoft© Flight Simulator X (FSX). I …

Experimental And Numerical Study Of The Air Distribution In An Airliner Cabin, Wei Liu

Open Access Theses

Nowadays, more people, including those with impaired health or who are otherwise potentially sensitive to the cabin environment, are traveling by air than ever before. The flying public demands a higher comfort level and a cleaner environment because they encounter a combination of environmental factors including low humidity, low air pressure, and sometimes, exposure to air contaminants such as ozone, carbon monoxide, various organic chemicals, and biological agents. Moreover, international air travel has increased the potential risks associated with airborne disease transmission and the release, whether accidentally or intentionally, of noxious substances during flight. Many studies suggest that the risk …

Effects Of Crossflow In An Internal-Cooling Channel On Film Cooling Of A Flat Plate Through Compound-Angle Holes, Zachary Taylor Stratton

Open Access Theses

The film-cooling holes in turbine blades are fed from an internal cooling channel. This channel imposes a crossflow at the entrance of the holes that can significantly affect the performance of the cooling jets that emanate from those holes. In this study, CFD simulations based on steady RANS with the shear-stress transport (SST) and the realizable k -ε turbulence models were performed to study film cooling of a flat plate with cooling jets issuing from eight round holes with a compound angle of 45 degrees, where the coolant channel that fed the cooling jets was oriented perpendicular to the direction …

Biaxial Shear/Tension Failure Criteria Of Spectra Single Fibers, Jianzhuo Sun

Open Access Theses

An experimental study was conducted to develop the biaxial failure surface criteria of single Spectra 130d and 100d filaments in a torsion-tension environment. The cross-sectional profiles of single Spectra fibers were investigated using scanning electron microscopy and X-ray computed tomography. A pin-gripping method to fix the ends of a polyethylene single fiber was developed. Effects of pin diameter on failure stress for both Spectra 130d and 100d were characterized. It was found that the perturbed stress field effect can be neglected when the pin diameter is larger than 0.8 mm. Additionally, the effect of the sample's gage length on fiber …

Feasibility Analysis Of Large Length-Scale Thermocapillary Flow Experiment For The International Space Station, Samantha Jean Alberts

Open Access Theses

The investigation of microgravity fluid dynamics emerged out of necessity with the advent of space exploration. In particular, capillary research took a leap forward in the 1960s with regards to liquid settling and interfacial dynamics. Due to inherent temperature variations in large spacecraft liquid systems, such as fuel tanks, forces develop on gas-liquid interfaces which induce thermocapillary flows. To date, thermocapillary flows have been studied in small, idealized research geometries usually under terrestrial conditions. The 1 to 3m lengths in current and future large tanks and hardware are designed based on hardware rather than research, which leaves spaceflight systems designers …

Blast Energy Mitigation In Porous Rocks, Brittany Corinne Essink

Open Access Theses

Geo-materials are commonly used and sought after for blast mitigation applications due to their wide availability and low cost compared to industry trademarked materials. Characterization of these natural geo-materials such as volcanic rocks is of paramount importance in determining their blast mitigation capabilities. While there is a large amount of information available for materials such as concrete or sand blasts, information on the properties of volcanic rocks is far more scarce. This lack of data is due to the wide range of existing natural volcanic rocks and the variation in the minerals and pore structures of the rocks.

In this …

Eps Power Supply Tech, Jeffrey Kruth

Robert "Bob" Twiggs STEM Education Collection

A technology report by Jeff Kurth on "EPS Power Supply Tech" from April 1, 2014.

Design And Implementation Of An Aircraft Human-In-The-Loop Engineering Simulator, Joshua Reed

Mechanical & Aerospace Engineering Theses & Dissertations

Simulation is a powerful tool for examining a dynamic system or process, but ensuring the model represents the real world sufficiently well for a given objective is difficult. This thesis will present and explain the methodology used to design a Human-In-The-Loop Engineering Aircraft Simulator. For aircraft simulation, numerical methods must be employed to perform the calculations required. The number of required calculations per second is computationally and resource expensive. Some existing aircraft simulations trade off mathematical accuracy of the model so available computing power can be used to run a human interface. Conversely, another simulator may have a very poor …

Design And Construction Of A Reconfigurable Pilot-In-The-Loop Aircraft Simulation Workstation, John J. Miller

Mechanical & Aerospace Engineering Theses & Dissertations

This thesis presents and explains the methodology used to design and construct an aircraft dynamics simulation workstation. Beginning from an outdated Navy T-34 training simulator, a gift to the school by the Naval Aerospace Medical Research Laboratory via a previous student, a new system was created to allow an engineer and/or pilot to manually control and evaluate vehicle characteristics for the purposes of research, development, and testing. Retaining only the superstructure of the original T-34 trainer, the entire system was re-engineered to provide a functional, immersive, and expandable simulation environment, complete with a five-screen visual system covering 97.5 deg of …

Fluid-Structure Interaction Modeling Of A F/A-18 Twin-Tail Buffet Using Non-Linear Eddy Viscosity Models, Ahmed M. Nagib M. Elmekawy

Mechanical & Aerospace Engineering Theses & Dissertations

When turbulent flow generates unsteady differential pressure over an aircraft's structure, this may generate buffeting, a random oscillation of the structure. The buffet phenomenon is observed on a wide range of fighter aircraft, especially fighters with twin-tail. More research is needed to better understand the physics behind the vortical flow over a delta wing and the subsequent tail buffet.

This dissertation reports the modeling and simulation of a steady-state one-way fluid-structure interaction for the tail buffet problem observed on a F/A-18 fighter. The time-averaged computational results are compared to available experimental data. Next, computations are extended to simulate an unsteady …

The Relationship Among Hfacs Levels And Analysis Of Human Factors In Unmanned And Manned Air Vehicles, Veysel Yesilbas

Engineering Management & Systems Engineering Theses & Dissertations

This dissertation analyzes the structural relationships among the Human Factors Accident Classification System levels for unmanned air vehicle and manned air vehicle accidents and the common relationships between unmanned air vehicle and manned air vehicle accident causes. The study acquired DOD HFACS accident classification data from 347 United States Air Force Class A accident reports for the years between 2000 and 2013.

The dissertation utilized a set of analysis that is considered to contribute substantially to the respective domain of the study. The correlations found among categorical levels were applied to HFACS taxonomy based on the Reason Model via path …

State Variable Model For Unsteady Two Dimensional Axial Vortex Flow With Pressure Relaxation, Mazin Mohammed Elbakri Abuharaz

Mechanical & Aerospace Engineering Theses & Dissertations

This research has utilized a state variable model for unsteady two dimensional axial vortex flows experiencing non-equilibrium pressure gradient forces. The model was developed successfully using perturbed radial and azimuthal momentum equations and a pressure Poisson's equations. Three main regions of the axial vortex flow were highlighted in this study including: a laminar core region, a non-equilibrium pressure envelope, and an outer potential vortex.

Linear stability theory was utilized to formulate the model and the perturbation functions were assumed to be of the Fourier type. The flow parameters considered were the Reynolds numbers, ranging between 6,000 and 14,000, and a …

System Identification Of An Autonomous Surface Vehicle, Christopher John Cook

Mechanical & Aerospace Engineering Theses & Dissertations

The modeling and system identification of a small pontoon based marine craft, without rudder control, in a controlled environment. Old Dominion University's autonomous surface vehicle was modeled using the Observer/Kalman System Identification method. The experimental position data was collected using a laser positioning system along with Arduino based sensors on board the boat to collect the motor speeds of the dual outboard motors. The data was then compiled using the System/ Observer/Controller Identification Toolbox to derive a dynamic model that is capable of providing path estimation and prediction information to the autonomous robotic system.

Integrating Mammalian Hazards With Management At U.S. Civil Airports: A Case Study., Kristin M. Biondi, Jerrold L. Belant, James A. Martin, Travis L. Devault, Guiming Wang

United States Department of Agriculture Wildlife Services: Staff Publications

Wildlife incidents with U.S. civil aircraft cost an estimated $1.4 billion from 1990 to 2010, with mammals 5 times more likely to cause damage than other wildlife. We surveyed 2 general aviation (GA) airports and 6 Part-139 certificated (i.e., certified) airports to assess efficacy of management practices for mammalian species hazardous to aircraft. We obtained information on mammalian species present on airport grounds, types and estimated effectiveness of management techniques, and effort spent on wildlife management. We evaluated management techniques relative to aircraft–wildlife collisions (i.e., incident) frequencies taken from Federal Aviation Administration’s (FAA) National Wildlife Strike Database and species hazard …

3d Aerodynamic Optimization Of Nrel Vi Wind Turbine Blade For Increased Power Output And Visualization Of Flow Characteristics, Tsewang Rabga Shrestha

Doctoral Dissertations and Master's Theses

The thesis focuses on the aspect of optimization of NREL VI wind turbine blade for increased power output using commercial solver ANSYS 14.5. The power curve obtained from BEMT, Baseline NREL VI CFD Simulations and Optimized Blade Simulations are compared with experimental results. Over prediction is observed in the theoretical result while computational analysis under predicts power produced at post stall region. Parameter correlation and sensitivity analysis study relates the effectiveness of design parameters on the objective outcome. Scatter plots and Determination Matrix indicate the problem setup as non-linear quadratic. Adaptive Single Objective Optimization algorithm is used for the optimization …

Evaluation Of Mixing-Limited Quasi-Global Wind-Us Model For Hifire 2 Flowpath, Michael R. Borghi Jr.

Doctoral Dissertations and Master's Theses

A Reynolds-averaged Navier-Stokes computational model featuring a mixing-limited, quasi-global chemical kinetics approach for an ethylene-methane fuel mixture is described and used in a validation effort against the Hypersonic International Flight Research Experimentation (HIFiRE) Direct Connect Rig experimental data for flight Mach numbers of 5.84, 6.5, and 8.0. An average error level between the numerical predictions and corresponding experimental measurements for static pressure along the engine flowpath is found to be within approximately 10%, for the two lowest Mach number cases, without calibration. Key features of the numerical flowfield development are identified, including regions within the combustor found to be significantly …