Aerospace Engineering Commons^™

Structural Analysis Of Microsatellites, Yezad H. Anklesaria

Masters Theses

"Satellite design, development, fabrication, testing and entry into service is a complex process. Each step of this process involves intricate steps to achieve the desired objective. This thesis summarizes a study relating to the area of development and testing of microsatellites to support qualification and eventually preparing a spacecraft for spaceflight. Students in the Space Systems Engineering laboratory (SSE Lab) in the Aerospace Engineering Program are in the process of developing a pair of microsatellites for a technology demonstration in space.

After the initial design of the spacecraft is completed in the design phase a significant amount of time is …

Gray Gas Analysis Of Radiative Preheating Effects On Shock Induced Combustion, Pratibha Raghunandan

Masters Theses

"The use of detonations in combustors has been receiving increased attention in recent times. The presence of shock waves in such combustors invariably poses the existence of two domains that present different physics for the flow processes. The variation of upstream temperature due to radiative heating by the products of combustion was given particular attention in the present study. The modeling of heat transfer across a normal shock wave of negligible thickness was done by considering the reactants and the products of combustion to be in radiative equilibrium with each other. The quantification of emissivity of the products of combustion …

Aerodynamics And Control Of A Deployable Wing Uav For Autonomous Flight, Michael Thamann

Theses and Dissertations--Mechanical Engineering

UAV development and usage has increased dramatically in the last 15 years. In this time frame the potential has been realized for deployable UAVs to the extent that a new class of UAV was defined for these systems. Inflatable wing UAVs provide a unique solution for deployable UAVs because they are highly packable (some collapsing to 5-10% of their deployed volume) and have the potential for the incorporation of wing shaping. In this thesis, aerodynamic coefficients and aileron effectiveness were derived from the equations of motion of aircraft as necessary parameters for autonomous flight. A wind tunnel experiment was performed …

Instrumentation, Control And Torch Ignition Systems Development For Lox/Methane Propulsion Research, Jesus Betancourt-Roque

Open Access Theses & Dissertations

A liquid propulsion research facility has been developed at the Center for Space Exploration Technology Research at The University of Texas at El Paso. This facility has capabilities for producing up to 25 liters of Liquid Methane, feeding LOX/Methane propellants to 100 N class thrusters and conducting automated steady state and pulsing combustion experiments. This work describes the design, development and testing process of the Data Acquisition and Remote Control System developed to integrate an Altitude Simulation System, a Cryogenic Delivery System, and multiple rocket combustors and thrusters. A Torch Ignition System development is detailed as well as the evaluation …

Operation Of The Aerodynamic Plasma Actuator At High Altitude, Timothy Glen Nichols

Masters Theses

"A plasma actuator was operated at altitudes from 0 to 18288 meters to determine the mechanisms leading to decreased force production at low pressures. The actuator was driven with a 5 kHz sine wave and a peak to peak voltage of 13.4 kV at pressures of 760, 429, 321, 226, and 88 Torr. A passive measurement technique called the capacitive V-dot probe was adapted to the actuator in order to resolve the spatiotemporal evolution of the surface potential and electric field on the dielectric surface. At low pressures up to 20 times more plasma is present than at atmospheric conditions. …

Effects Of Riblets On Skin Friction And Heat Transfer In High-Speed Turbulent Boundary Layers, Lian Duan, Meelan M. Choudhari

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Direct numerical simulations of spatially developing turbulent boundary layers over riblets are conducted to examine the effects of riblets on skin friction and heat transfer at high speeds. Zero-pressure gradient boundary layers under two flow conditions (Mach 2.5 with Tw/Tr = 1 and Mach 7.2 with Tw/Tr = 0.5) are considered. Simulations are conducted for boundary-layer flows over a clean surface and symmetric V-groove riblets. The DNS results at Mach 2.5 confirm the few existing experimental observations and show that a drag reduction of approximately 7% can be achieved for riblets with proper spacing. The comparisons in turbulence statistics and …

A Filter-Forcing Turbulence Model For Large Eddy Simulation Incorporating The Compressible "Poor Man's" Navier--Stokes Equations, Joshua Strodtbeck

Theses and Dissertations--Mechanical Engineering

A new approach to large-eddy simulation (LES) based on the use of explicit spatial filtering combined with backscatter forcing is presented. The forcing uses a discrete dynamical system (DDS) called the compressible ``poor man's'' Navier--Stokes (CPMNS) equations. This DDS is derived from the governing equations and is shown to exhibit good spectral and dynamical properties for use in a turbulence model. An overview and critique of existing turbulence theory and turbulence models is given. A comprehensive theoretical case is presented arguing that traditional LES equations contain unresolved scales in terms generally thought to be resolved, and that this can only …

Design And Flight Testing Of A Warping Wing For Autonomous Flight Control, Edward Brady Doepke

Theses and Dissertations--Mechanical Engineering

Inflatable-wing Unmanned Aerial Vehicles (UAVs) have the ability to be packed in a fraction of their deployed volume. This makes them ideal for many deployable UAV designs, but inflatable wings can be flexible and don’t have conventional control surfaces. This thesis will investigate the use of wing warping as a means of autonomous control for inflatable wings. Due to complexities associated with manufacturing inflatable structures a new method of rapid prototyping deformable wings is used in place of inflatables to decrease cost and design-cycle time. A UAV testbed was developed and integrated with the warping wings and flown in a …

Low Reynolds Number Flow Field Modification Via Travelling Wave Actuation Of A Vertically Aligned Wire Array Surface, John C. Calhoun

Theses and Dissertations--Mechanical Engineering

Experiments were conducted to observe the effects of an active wire surface on low-Reynolds number Poiseuille flow. The objective was to evaluate the feasibility of actuating piezoelectric nanowires into a travelling wave motion in order to reduce wall shear stress in turbulent flows. Studies have shown that travelling wave motions introduced into the bounding wall of turbulent flow can reduce wall shear stress by disrupting the formation of drag-inducing coherent vortical structures. A Reynolds number scaled flow facility was designed to represent the near-wall region of turbulent flow. A wire surface was installed in the bounding wall and dynamically actuated …

A Study Of The Integration Of An Inlet Noise Radiation Code With The Aircraft Noise Prediction Program, Devin Kyle Boyle

Masters Theses

"A numerical method has been developed in order to study the effect of turbofan inlet acoustic treatment on the resulting cumulative noise heard by observers on the ground. The approach to creating the tool was to combine the capabilities of the NASA-developed Aircraft Noise Prediction Program (ANOPP) with the fan noise propagation and radiation code developed at Missouri University of Science and Technology. ANOPP can be used to predict the noise metrics resulting from a typical commercial aircraft with turbofan engines on several different flight profiles, including takeoff, approach/landing and a steady (constant altitude/airspeed) flyover. These capabilities are valuable for …

Ua94/6/8 Student / Alumni Personal Papers Wku Terry Wilcutt, Wku Archives

WKU Archives Collection Inventories

Records created by and about Terry Wilcutt and manned space flights.

Studies Of Inductive Plasmas And Their Application To Theta-Pinch Devices Via Numerical Modeling, Warner C. Meeks

Masters Theses

"First, a globally-averaged RF plasma model is used to investigate exit conditions immediately following a RF pre-ionization stage. Analysis shows that reducing pulse duration from 10⁻⁶ to 10⁻⁷ seconds increases peak ion energy fraction by 17% (from 16 to 33%) and doubles final conductivity. Pulse waveforms are square in nature, and ion energy fraction is defined in this work as the percentage of total input energy entrained in ions. Increasing total energy deposition from 5 to 160 mJ increases ion energy fraction from 33% to 58% at a 200 ns pulse duration. This increase is not linear however, showing instead …

Defining, Teaching, And Assessing Engineering Design Skills, Nikos J. Mourtos

Nikos J. Mourtos

The paper discusses a systematic approach for defining, teaching, and assessing engineering design skills. Although the examples presented in the paper are from the field of aerospace engineering, the principles apply to engineering design in general. What makes the teaching of engineering design particularly challenging is that the necessary skills and attributes are both technical and non-technical and come from the cognitive as well as the affective domains. Each set of skills requires a different approach to teach and assess. Implementing a variety of approaches for a number of years at SJSU has shown that it is just as necessary …

Real-Time Strategies For Enhancing Aircraft Performance In Wind, Kamran Turkoglu

Kamran Turkoglu

This thesis presents real-time guidance strategies for unmanned aerial vehicles (UAVs) that can be used to enhance their flight endurance by utilizing insitu measurements of wind speeds and wind gradients. In these strategies, periodic adjustments can be made in the airspeed and/or heading angle command for the UAV to minimize a projected power requirement at some future time. In this thesis, UAV flights are described by a three-dimensional dynamic point-mass model. A stochastic wind field model has been developed not only to reflect the mean wind magnitude behaviour in both vertical and horizontal axis, but also has it been extended …

Inherent And Model-Form Uncertainty Analysis For Cfd Simulation Of Synthetic Jet Actuators, Daoru Frank Han, Serhat Hosder

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A mixed (aleatory and epistemic) uncertainty quantification (UQ) method was applied to computational uid dynamics (CFD) modeling of a synthetic jet actuator. A test case, (ow over a hump model with synthetic jet actuator control) from the CFDVAL2004 work-shop was selected to apply the Second-Order Probability framework implemented with a stochastic response surface obtained from Quadrature-Based Non-Intrusive Polynomial Chaos (NIPC). Three uncertainty sources were considered: (1) epistemic (model-form) uncertainty in turbulence model, (2) aleatory (inherent) uncertainty in free stream veloc-ity and (3) aleatory uncertainty in actuation frequency. Uncertainties in both long-time averaged and phase averaged quantities were quantified using a …

Geographical Assessment Of Microalgae Biofuels Potential Incorporating Resource Availability, Jason C. Quinn, Kimberly Catton, Sara Johnson, Thomas H. Bradley

Mechanical and Aerospace Engineering Faculty Publications

Previous assessments of the economic feasibility and large-scale productivity of microalgae biofuels have not considered the impacts of land and carbon dioxide (CO2) availability on the scalability of microalgae-based biofuels production. To accurately assess the near-term productivity potential of large-scale microalgae biofuel in the US, a geographically realized growth model was used to simulate microalgae lipid yields based on meteorological data. The resulting lipid productivity potential of Nannochloropsis under large-scale cultivation is combined with land and CO2 resource availability illustrating current geographically feasible production sites and corresponding productivity in the US. Baseline results show that CO2 transport constraints will limit …

The Key Ideas Of Mdw Viii: A Summary, Aaron Altman, Clive L. Dym, Ray Hurwitz, John W. Wesner

Mechanical and Aerospace Engineering Faculty Publications

This paper summarizes and highlights the presentations and discussions that took place during Mudd Design Workshop VIII, ‘Design Education: Innovation and Entrepreneurship,’ at Harvey Mudd College. This paper also describes both the key ideas that emerged from the presentations and discussions of the participating engineering design educators, practitioners and researchers, and the methodology used to capture and retain those ideas. Additionally, this paper proposes a framework of design competencies that were created and evolved by the workshop’s participants as a response to a question posed at one of the workshop sessions: ‘What are the minimum design competencies students should learn …

Encyclopedia Of Mathematics And Society: 'Engineering Design', Kimberly Edginton Bigelow

Mechanical and Aerospace Engineering Faculty Publications

Engineers design everything from automobiles and bridges to prosthetic limbs and sporting equipment. Designing is different from simply building in that it requires the adherence to a very systematic, yet iterative, process known as the “engineering design process.” This process is to engineers what the scientific method is to scientists-guiding steps that help ensure that the end result is the best it can be. When a new product is created without following the steps of the engineering design process, there is a higher likelihood that the product designed will lack some important aspect: the end product may not appropriately account …

A Systematic Approach For Real-Time Operator Functional State Assessment, Guangfan Zhang, Wei Wang, Aaron Pepe, Roger Xu, Tom Schnell, Nick Anderson, Dean Heitkamp, Jiang Li, Feng Li, Frederick Mckenzie

Electrical & Computer Engineering Faculty Publications

A task overload condition often leads to high stress for an operator, causing performance degradation and possibly disastrous consequences. Just as dangerous, with automated flight systems, an operator may experience a task underload condition (during the en-route flight phase, for example), becoming easily bored and finding it difficult to maintain sustained attention. When an unexpected event occurs, either internal or external to the automated system, the disengaged operator may neglect, misunderstand, or respond slowly/inappropriately to the situation. In this paper, we discuss an approach for Operator Functional State (OFS) monitoring in a typical aviation environment. A systematic ground truth finding …

Large-Eddy Simulation Of Axially-Rotating, Turbulent Pipe And Particle-Laden Swirling Jet Flows, Nicolas D. Castro

Mechanical & Aerospace Engineering Theses & Dissertations

The flows of fully-developed turbulent rotating pipe and particle-laden swirling jet emitted from the pipe into open quiescent atmosphere are investigated numerically using Large-Eddy Simulation (LES). Simulations are performed at various rotation rates and Reynolds numbers, based on bulk velocity and pipe diameter, of 5.3x103, 12x103, and 24x103, respectively. Time-averaged LES results are compared with experimental and simulation data from previous studies. Pipe flow results confirm observations in previous studies, such as the deformation of the turbulent mean axial velocity profile towards the laminar Poiseuille-profile, with increased rotation. The Reynolds stress anisotropy tensor shows a redistribution due to pipe rotation. …

Prevailing Torque Locking Feature Wear-Out, Adam Joseph Charles Zimandy

USF Tampa Graduate Theses and Dissertations

This thesis provides much needed representative sample data for reuse life of fully seated and torqued locknuts. Most national requirements for prevailing torque locking fasteners only specify unseated reuse life. This could create a potentially dangerous situation if unseated is misinterpreted for seated. This thesis provides comparative data for seated verses unseated configuration. Six aerospace, 3 all-metal and 3 nylon insert, and one non-aerospace locknuts were tested at preloads levels of unseated, 66%, 75%, and 85% of yield of bolt. The locknuts tested are MS21043-4, NAS1291-4, NAS1805-4, MS17825-4, MS21044D4, NAS1021N4, and Grade 8. A fixture was created in order to …

Orbital Evasive Target Tracking And Sensor Management, Huimin Chen, Genshe Chen, Dan Shen, Erik P. Blasch, Khanh Pham

Huimin Chen

In this chapter, we consider the sensor management problem for tracking space targets where the targets may apply evasive maneuvering strategy to avoid being tracked by the space borne observers. We first study the case of single target tracking by a single observer and formulate the pursuit–evasion game with complete information. Then we extend the tracking problem to a set of collaborative observers and each observer has to decide when to sense which target in order to achieve the desired estimation error covariance. A popularly used criterion for sensor management is to maximize the total information gain in the observer-to-target …

Reconfiguration Of The Receiver System For Sodium Doppler Wind/Temperature Lidar, Vardan Semerjyan, Tao Yuan

Vardan Semerjyan

Sodium (Na) Faraday filters based spectrometer is a relatively new instrument to study sodium nightglow [Harrell et al., 2010] as well as atmospheric chemistry in the mesopause region. Successful spectrometer measurement demands highly accurate control of filter temperature. The ideal operation site for this Na spectrometer would be an isolated location with minimum nocturnal sky background. Thus, the remote and automatic control of the filter temperature is a requirement for such operation, whereas current temperature controllers can only be adjusted manually by the operator. The proposed approach is aimed not only to enhance the accuracy of the temperature control but …

Erau Aviation Wildlife Hazard Newsletter, Paul F. Eschenfelder

Paul F. Eschenfelder

No abstract provided.

Open Orbiter Communications, Outreach & Policy, Josh Berk, Anders Nervold, Jeremy Straub

Jeremy Straub

No abstract provided.

Open Orbiter Cubesat Communication Protocol, Zahirul Islam, Ernest Workman, Nick Schmitz, Noah Root, Josh Berk, Jeremy Straub

Jeremy Straub

No abstract provided.

Optical System For Open Orbiter, Nick Long, Dillon Hasselmenn, Rachael Roberts, Patrick Galegher, Noah Root, Josh Berk, Jeremy Straub

Jeremy Straub

No abstract provided.