Digital Commons Network^™

Global Skin Friction Diagnostics In Complex Separated Flows, Sudesh A. Woodiga

Masters Theses

This work describes the application of a global luminescent oil film skin friction meter to quantitative global skin friction diagnostics in complex separated flows. The development of this technique is based on the relationship between the oil film thickness and luminescent intensity of an oil film mixed with a luminescent dye. The projected thin oil film equation is given to relate the normalized luminescent intensity with skin friction. The basis for this technique is the variational solution for the thin oil film equation on the image plane. The variational formulation with a smoothness constraint on skin friction is proposed to …

Analysis Of Cavity Flow And The Effects Of A Rod In Crossflow, Richard David Loewen

Masters Theses

Subsonic cavity flow tests of an L/D = 3.5 cavity, with three different diameter rods in crossflow, 1/8", 3/16", and 1/4", were conducted using the High Speed Wind Tunnel in the University of Tennessee Space Institute’s Gas Dynamic Laboratory. The average Mach number flow over the duration of the four phase testing sequence was 0.52, with a unit Reynolds number of 13.8 x 106. With the use of a dynamic pressure transducer and a laser PIV system, Spectral and Flow Visualization data was collected with aim of investigating the effect of the rods in crossflow on cavity flow. However, for …

Optimizing The Use Of The United States Army Oh-58d Helicopter Simulator And Aircraft For Full-Authority Digital Electronic Control Manual Throttle Training, Conrad Rodgers

Masters Theses

Over the past decade the United States Army has used a Full-Authority Digital Electronic Control (FADEC) system to control fuel flow to the engine of the OH-58D helicopter. Currently, part of the training is primarily conducted for the scenario of a FADEC system failure in the aircraft. Because of the complexity of this task, a number of accidents have occurred resulting in minor to severe damage to the aircraft. The United States Army has recently fielded two OH-58D Operational Flight Training Simulators in an effort to increase training efficiency and effectiveness. It is anticipated that the simulators will provide a …

Preliminary Design, Flight Simulation, And Task Evaluation Of A Mars Airplane, Dodi Deanne Walker

Masters Theses

A limited aerodynamic, stability and control, and task evaluation of a new rocket-powered Mars airplane design was conducted. The Mars airplane design, designated the Argo VII, was patterned after the NASA ARES-2 design. The aerodynamic and stability and control parameters of the Argo VII were determined using analytical and computational techniques and were comparable to those of the ARES-2. The Argo VII was predicted to be statically stable and damped in all axes on Earth and Mars. A series of flight tests were performed using a MATLAB Simulink-based flight simulation program to assess the performance, longitudinal flying qualities, and mission …

Analysis Of Carbon Fiber Characterization Techniques, Heather Darlene Cochran

Masters Theses

Accurate and efficient fiber characterization is critical to developing a successful process for producing low cost, high quality carbon fibers from pitch. This study analyzes current methods for characterizing diameter, tensile strength, and tensile modulus for carbon fibers using a Dia-stron® automated system consisting of a FDAS 765 laser scan micrometer and a LEX 810 linear extensometer. Fiber diameters measured by the Dia-stron® system are compared with diameters measured by Scanning electron microscope (SEM) and by optical microscope at 20X and 40X magnifications. Tensile measurements were also analyzed. This study found that fiber alignment during tensile testing is critical to …

A New Fully Implicit In Time Two-Dimensional Inverse Heat Conduction Method, Bryan S. Elkins

Masters Theses

A new combination of methods used to solve the transient, two-dimensional inverse heat conduction problem (IHCP) is presented in this thesis. A simple implicit in time with space marching approach is used in combination with digital filtering for regularization. Results are presented for both one-dimensional and two-dimensional problems. As much as 10% measurement error is added to the data to simulate experimental results.

One-dimensional results with “perfect” data suggested that refining the spatial and temporal meshes improved the accuracy of the inverse solution. However, the nodal Fourier number was found to have no effect on accuracy. Further investigation into the …

Performance Analysis Of Skip-Glide Trajectories For Hypersonic Waveriders In Planetary Exploration, Ngoc-Thuy Dang Nguyen

Masters Theses

A performance analysis for skip and glide is being studied to investigate the potential usage of waverider technology for interplanetary explorations. While the skip and glide equations themselves were first explored by Eggers, this thesis will implement his equations, but then add waverider technology, to determine the possibility of using trajectory assist to navigate around four planets (Earth, Mars, Jupiter and Venus). All trajectory calculations will be based on the waverider lift-to-drag ratios for various planets to determine the maximum range distance. For this research, skip and glide trajectory will be handled separately to determine which is best suited in …

A Limited Evaluation Of Pilot Technical Performance, Situational Awareness, And Workload When Flying With An Airframe-Referenced 3d Audio Display, Alan Joseph Wigdahl

Masters Theses

The visual workload of general aviation pilots operating alone in adverse conditions is often high. Airframe-referenced 3D audio systems may improve safety and performance by transferring a portion of this workload to the audio modality. These systems use the aircraft’s axes as a reference to present audio directional cues to the pilot via a headset.

This experiment compared the technical performance, workload, and situational awareness of pilots as they performed instrument flight procedures with and without an airframe-referenced 3D audio system. Five pilot participants flew six tasks of each audio condition in a Piper Navajo aircraft modified with a 3D …

Manufacturing Of Transparent Composites Using Vacuum Infusion Process, Jason Niles Gallagher

Masters Theses

"Glass is the most commonly used transparent material. However, glass is not suitable where low weight and high strength are required. For many applications there exists a need for mechanically strong composite materials of high optical quality and transparency equivalent to window glass. Glass fiber reinforced transparent composite is a viable solution. Transparency is maintained by precisely matching the refractive index of the matrix with that of the glass fiber. Aircraft canopies and transparent armor can be potential applications for this new class of materials.

In the present work, transparent composites are manufactured using vacuum infusion process. Both rectangular glass …

Analysis Of Access-To-Space Missions Utilizing On-Board Energy Management And Entropic Analysis, Tyler Winter

Masters Theses

"The overall objective of this study is the thermodynamically consistent quantification of second-law and performance losses for vehicle configurations implemented or suggested for access-to-space missions and the development of the relationships between the mission entropy generation and overall mission performance. The detailed theory which allows thermodynamically rigorous loss accounting (entropy generation and direct relationship to vehicle performance) is developed and discussed for aerospace vehicles. A full vehicle trajectory code utilizing simplified models for multi-stage rockets and air-breathing propulsion systems is developed and validated specifically for use as a testbed for second law-based theory and concepts. Results are shown in which …