Aerospace Engineering Commons^™

Effect Of Cellular Phone And Radar Forensics On Search And Rescue Duration For General Aviation Aircraft Accidents In The Contiguous United States, Ryan J. Wallace

Journal of Aviation Technology and Engineering

Emergency Locator Transmitters (ELT) are generally the primary tool for locating distressed aircrews following an aircraft accident. In 2009, the International COSPAS-SARSAT organization ordered the cessation of 121.5 MHz ELT satellite monitoring to alleviate systemic false alarms and encourage pilots to upgrade ELTs to modern 406 MHz models. While most nations acquiesced to the mandate, the United States encountered severe resistance from pilot groups. As a result, 121.5 MHz ELTs are still in use in the U.S. but remain unmonitored by satellite systems. This study sought to assess the impact of alternative search methods such as radar and cellular phone …

Fundamental Studies Of Vortices Induced By A Vortex-Generator For Automotive Applications, Asiful Islam, Graham Doig

Aerospace Engineering

For automotive applications, passive flow control devices can be used to reduce, delay or prevent flow separation. This study explores the nature of vortex generation and behaviour, numerically and experimentally, for a simple geometry at a Reynolds Number (Rex) of 5×105 and 1.945×106. The setup comprised a triangular vane vortex-generator mounted on a shallow ramp referenced from literature. Flow over the isolated ramp was validated with past experimental particle-image-velocimetry (PIV) data, which also highlighted the relative performance of various turbulence models. A parametric study was undertaken with the vane orientation defined by an angle-of-attack (β) and stream-wise location (xedge/xVG). These …

Application Of Kriging To Motorsport Aerodynamic Analysis, Matthew Cruickshank, Graham Doig

Aerospace Engineering

Aerodynamic analysis in motorsport is conducted using three methods, computational, scaled experimental and full-scale operational. However, the varying fidelity, different sampling resolutions and unavoidable errors of each technique make valid comparisons between datasets from each method difficult and time consuming. Kriging is a geostatistical method to estimate values within a data field by examining and applying the trends of the dataset. This research examines how such techniques can be used to aid comparison between aerodynamic measurements of a race car. It examines how kriging can be used to transform discrete measurements, of varying fidelity and sampling resolution, into semi-continuous measurements, …

Computational Simulation Of An Altitude Adaptive Nozzle Concept, K. Schomberg, G. Doig, J. Olsen

Aerospace Engineering

A computational analysis of an annular converging-diverging (CD) and an altitude adaptive expansion-deflection (ED) nozzle is presented. Numerical results were generated using a 2D axisymmetric, pressure-coupled solver in conjunction with the Spalart-Allmaras turbulence closure model and second order spatial discretisation schemes. Results were recorded over a theoretical altitude range and compared to experimental static pressure readings and schlieren images. The correlation between numerical and experimental static pressure values was high for all cases. Comparison of schlieren imagery outlined the large variety of flow regions within the ED nozzle flow field. The interactions between these regions were highly sensitive to turbulence …

The Aerodynamics Of A Cornering Inverted Wing In Ground Effect, James Keogh, Graham Doig, Tracie J. Barber, Sammy Diasinos

Aerospace Engineering

For racing car configurations an inverted wing produces negative lift that allows increased levels of acceleration to be maintained through corners. Routine aerodynamic analysis, however, will typically be in the straight-line condition. A numerical analysis of the inverted T026 wing geometry through the curved path of a constant radius corner was conducted. The asymmetrical properties of the oncoming flow resulted in the introduction of a rolling and yawing moment along the span, as well as side-force. Yaw angle, flow curvature and a velocity gradient resulted in changes to the pressure distribution over the wing surface. Primary vortex behaviour was observed …

Autonomous Close Formation Flight Of Small Uavs Using Vision-Based Localization, Michael B. Darling

Master's Theses

As Unmanned Aerial Vehicles (UAVs) are integrated into the national airspace to comply with the 2012 Federal Aviation Administration Reauthorization Act, new civilian uses for robotic aircraft will come about in addition to the more obvious military applications. One particular area of interest for UAV development is the autonomous cooperative control of multiple UAVs. In this thesis, a decentralized leader-follower control strategy is designed, implemented, and tested from the follower’s perspective using vision-based localization.

The tasks of localization and control were carried out with separate processing hardware dedicated to each task. First, software was written to estimate the relative state …

Effect Of Stitch Density On Fatigue Characteristics And Damage Mechanisms Of Stitched Carbon/Epoxy Composites, Arief Yudhanto, Naoyuki Watanabe, Yutaka Iwahori, Hikaru Hoshi

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The effect of stitch density (SD) on fatigue life, stiffness degradation and fatigue damage mechanisms in carbon/epoxy (T800SC/XNRH6813) stitched using Vectran thread is presented in this paper. Moderately stitched composite (SD = 0.028/mm²; 'stitched 6 x 6') and densely stitched composite (SD = 0.111/mm²; 'stitched 3 x 3') are tested and compared with composite without stitch thread (SD = 0.0; 'unstitched'). The experiments show that the fatigue life of stitched 3 x 3 is moderately better than that of unstitched and stitched 6 x 6. Stitched 3 x 3 pattern is also able to postpone the …

Optimum Path Planning For An Impaired Aircraft, Suzannah Bailey

Renée Crown University Honors Thesis Projects - All

Proportionally speaking, it is safer to travel by plane than any other form of transportation. However, in some parts of the world such as Africa, the lack of updated aircraft, instability within the region, and inexperience of flight crews contribute to a higher rate of aircraft incidents and accidents. This capstone combines elements from aerospace engineering, as well as international relations to create a program to mitigate these risks.

This new algorithm, the Bailey Algorithm, is very different from the commonly used Dijkstra Algorithm. Unlike Dijkstra, the Bailey Algorithm not only incorporates the distance traveled between cities, but it also …

Experimental And Numerical Investigations Of Microdroplet Evaporation With A Forced Pinned Contact Line, Kevin Gleason

HIM 1990-2015

Experimental and numerical investigations of water microdroplet evaporation on heated, laser patterned polymer substrates are reported. The study is focused on both (1) validating numerical models with experimental data, (2) identifying how changes in the contact line infuences evaporative heat transfer and (3) determining methods of controlling contact line dynamics during evaporation. Droplets are formed using a bottom-up methodology, where a computer-controlled syringe pump supplies water to a ~200[micro]m in diameter fluid channel within the heated substrate. This methodology facilitates precise control of the droplets growth rate, size, and inlet temperature. In addition to this microchannel supply line, the substrate …

The Thermodynamics Of Planetary Engineering On The Planet Mars, Christopher Barsoum

HIM 1990-2015

Mars is a potentially habitable planet given the appropriate planetary engineering efforts. In order to create a habitable environment, the planet must be terraformed, creating quasi-Earth conditions. Benchmarks for minimum acceptable survivable human conditions were set by observing atmospheric pressures and temperatures here on Earth that humans are known to exist in. By observing a positive feedback reaction, it is shown how the sublimation of the volatile southern polar ice cap on Mars can increase global temperatures and pressures to the benchmarks set for minimum acceptable survivable human conditions. Given the degree of uncertainty, utilization of pressure scale heights and …

Design Optimization Of A Composite Wing Box For High-Altitude Long-Endurance Aircraft, Philip T. Arévalo

Doctoral Dissertations and Master's Theses

A design optimization process is developed to define the wing box structure for High-Altitude Long-Endurance Aircraft (HALE). The goal of this study is to determine the best tradeoff between mass and rigidity of a HALE aircraft wing structure. A preliminary composite laminate structural design procedure is described which uses a NASTRAN-based Finite Element Analysis (FEA), and the Hierarchical Evolutionary Engineering Design System (HEEDS) MDO software to define a locus of acceptable, optimized wing box design definitions.

The Effect Of The 2-Dimensional Magnetic Field Profile In Hall Thrusters, Megan Lewis Harvey

Doctoral Dissertations and Master's Theses

Electric propulsion engines, in particular Hall thrusters, provide the possibility of long-distance, low-cost space travel. The geometrical details of the Hall thrusters, especially the magnetic field prole, are crucial to improving their efficiency. The effect of the magnetic field structure was investigated using a simple, two-dimensional model, assuming axial symmetry. The previous one-dimensional conclusion, namely that the details of the shape of the magnetic field are unimportant, was confirmed. This result has implications for the design of future Hall thruster engines, with an eye toward maximizing their efficiency.

Winglet Performance Evaluation Through The Vortex Lattice Method, Phil R. Rademacher

Doctoral Dissertations and Master's Theses

The purpose of the study was to assess the possibility of retrofitting winglets to the Dassault Falcon 10 small size business jet using the vortex lattice method solver program SURFACES© by GreatOWL Publishing. The winglet geometric parameters investigated were the winglet span, cant angle, sweep and taper ratio in terms of their influence on drag, range, fuel burn, as well as wing root bending moments. The results of the research show that winglet span and cant angle offer the highest gains in terms of performance while taper ratio and sweep angle have a minor contribution. In general, all winglets provided …

Separation Bubbles And Vortex Formation In Cavity Flows, Kartheek Ravulapati

Doctoral Dissertations and Master's Theses

This research is a computational fluid dynamic study of the formation of vortices and separation bubbles in a square cavity as well as in a cylindrical cavity. Whereas there has been previous research work on the problem of a free stream over different types of cavities, like open and closed cavities or lid driven cavities, this research on an inlet induced flow inside a square cavity lead to unusual and interesting basic fluid dynamical phenomena. The flow in a square cavity and in a cylindrical cavity is simulated over a range of Reynolds numbers and the appearance of separation bubbles …

Flexible Slosh Diaphragm Modeling And Simulation In Propellant Tanks, Darren Vaughn Levine

Theses and Dissertations

iquid sloshing and propellant distribution is an important field of research for aerospace applications such as launch vehicles and spacecraft. The propellant mass behavior can greatly influence vehicle dynamics, altering trajectories and structural loading distributions. In order to combat these concerns some propellant tanks employ thin elastomeric diaphragms to separate the fuel from the gas volumes and restrict the fluid's motion. The diaphragm’s flexible behavior is generally highly nonlinear, and various propellant fill levels and acceleration conditions can cause large deflections resulting in complex buckling and folding patterns. When complex and non-uniform deformations occur, there is potential for diaphragm wear …

Uncertainty Quantification Of Photothermal Radiometry Measurements Using Monte Carlo Simulation And Experimental Repeatability, Austin Fleming

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Photothermal Radiometry is a common thermal property measurement technique which is used to measure the properties of layered materials. Photothermal Radiometry uses a modulated laser to heat a sample, in which the thermal response can be used to determine the thermal properties of layers in the sample. The motivation for this work is to provide a better understanding of the accuracy and the repeatability of the Photothermal Radiometry measurement technique. Through this work the sensitivity of results to input uncertainties will be determined. Additionally, using numerical simulations the overall uncertainty on a theoretical measurement will be determined.

The repeatability of …

Cti White Paper, Tim Brady, Gregory Mcguirk

Publications

The FAA Air Traffic Collegiate Training Initiative (AT-CTI) Program has 36 partner institutions across the United States which offer a variety of accredited academic degrees and actively promote a multicultural and diverse collegiate environment.

The Pocketqube Concept, Robert J. Twiggs, J. G. Jernigan, L. R. Cominsky, L. R. Malphrus, B. K. Silverman, K. Zack, S. Mcneil, W. Roach-Barrett, T-Logoqube

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs and associates titled "The PocketQube Concept" from April 23, 2014.

Performance Improvement Through Velocity Triangle Optimization-Driven Redesign For Mitigating The Horseshoe Vortex In Axial Turbines, Vladislav Shulman

Doctoral Dissertations and Master's Theses

Momentum differences between the neighboring streamlines at the end wall/primary flow interaction region of an axial turbine stage induce three-dimensional vortical flow structures, such as the leading edge horseshoe vortex, resulting in significant aerodynamic performance deterioration. Reducing the effect of such flow instabilities requires turbine blade modification to discourage boundary layer roll-up, but traditional structural modification design systems can be prohibitively complex and time-intensive.

To address this problem, this study contributes a blade modification method involving airfoil shape optimization, designed to adjust the leading edge airfoil shape in horseshoe vortex-affected turbine applications. The key insight is that airfoil design (treated …

Innovative Uses Of The Canisterized Satellite Dispenser (Csd), Robert J. Twiggs, Walter Holemans, Ryan Williams, Andrew Kalman, Rex Ridenoure, Tom Walkinshaw, Ryan Hevner, Floyd Azure

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Walter Holemans, Ryan Williams, Andrew Kalman, Robert Twiggs, Rex Ridenoure, Tom Walkinshaw, Ryan Hevner, and Floyd Azure titled "Innovative Uses of the Canisterized Satellite Dispenser (CSD)" from April 16, 2014.