Radar Based Navigation In Unknown Terrain, Kyle J. Kauffman

Theses and Dissertations

There is a great need to develop non-GPS based methods for positioning and navigation in situations where GPS is not available. This research focuses on the development of an Ultra-Wideband Orthogonal Frequency Division Multiplexed (UWB-OFDM) radar as a navigation sensor in GPS-denied environments. A side-looking vehicle-fixed UWB-OFDM radar is mounted to a ground or aerial vehicle continuously collecting data. A set of signal processing algorithms and methods are developed which use the raw radar data to aide in calculating the vehicle position and velocity via a simultaneous localization and mapping (SLAM) approach. The radar processing algorithms detect strong, persistent, and …

Near-Wake Flow Dynamics Of A Horizontal Axis Wind Turbine, Pooyan Hashemi Tari

Electronic Thesis and Dissertation Repository

Experiments have been conducted in a large wind tunnel set-up in order to study the flow structures within the near-wake region of a horizontal axis wind turbine. Particle Image Velocimetry (PIV) has been employed to quantify the mean and turbulent components of the flow field. The measurements have been performed in multiple adjacent horizontal planes in order to cover the area behind the rotor in a large radial interval, at several locations downstream of the rotor. The measurements were phase-locked in order to facilitate the re-construction of the three-dimensional flow field. Acquiring uniform particle distribution in the measurement planes as …

The Effects Of Observations And Maneuvers On Orbit Solutions, Christine M. Schudrowitz

Theses and Dissertations

The purpose of this research is to characterize the performance of the optimal sequential filter used in ODTK with a maneuvering satellite. Specifically, this thesis sought to characterize the performance using two scenarios: performance with a maneuver in between passes and performance with a limited number of measurements. The performance of the filter is evaluated by analyzing the covariance values generated during the orbit estimation process. Larger covariance values signify reduced performance of the filter. Several variables for the maneuvering satellite are used, including the maneuver direction and the maneuver magnitude. The time of the maneuver is also varied, which …

The Near Wake Of A European Starling, Adam J. Kirchhefer

Electronic Thesis and Dissertation Repository

The wake of a freely flying European starling (Sturnus vulgaris) was measured using high speed, time-resolved, particle image velocimetry, simultaneously with high speed cameras which imaged the bird. These measurements have been used to generate vector maps in the near wake that can be associated with the bird’s location and wing configuration. A kinematic analysis has been performed on select sequences of measurements to characterize the motion of the bird, as well as provide a point of comparison between the bird of the present study and other birds or flapping wings. Time series of measurements have been expressed …

Predicting The Wear Of High Speed Rocket Sleds, Lauren B. Wuertemberger

Theses and Dissertations

Holloman Air Force Base houses the 10 mile long Holloman High Speed Test Track (HHSTT) in New Mexico and can run hypersonic experiments at speeds up to 10,000m/s. Tested objects are loaded onto sleds, which are connected to the track by slippers that slide along the rails. The payload sled is propelled down the track by a series of rocket sleds. The ability to predict the wear that will occur on the slippers during these experiments is important for slipper design and preventing catastrophic failure. However, high speeds complicate wear prediction as there additional contributing factors, including inconsistent surface contact, …

Merrill-Cazier Library Gas Exhibition, Betty Rozum, Andrew Wesolek, Pamela N. Martin

Andrew Wesolek

This exhibition, presented in the Merrill-Cazier Library, captured the history and accomplishments of the GAS program. Click the download button to see a PowerPoint presentation featuring images and text from the exhibition.

Solar Energy Collection Analysis Tool For Conceptual Aircraft Design, Grant Glazebrook

Aerospace Engineering

As battery energy storage and solar cell technology improve, solar aircraft are increasingly being considered for High Altitude Long Endurance missions. Although solar vehicles may theoretically remain on-station indefinitely using the sun as a power source, their design and feasibility is sensitive to mission planning details as specific as the time history of the vehicle’s deck orientation relative to the sun; the energy available for capture by the on-board solar array is governed by the solar incidence angle, and at certain orientations, the vehicle may cast shadows on itself and further reduce its energy capture capabilities. To quantify these losses, …

The Architecture Selection, Design, And Discharge Modeling Of A Passive Compensation, Iron-Core, Two-Phase, Permanent Magnet Compulsator To Power A Small Railgun Platform, Collin Macgregor

Aerospace Engineering

The goal of this project was to design and build a compensated pulsed alternator, or compulsator, to power the Cal Poly Electromagnetic Railgun Mark 1.1. This project examines the feasibility of implementing mechanical pulsed power supplies for repeatable use with a railgun load for orbital debris hypervelocity testing. The final system architecture chosen was a passively compensated, iron-core, 2-phase, permanent magnet compulsator. The Cal Poly Compulsator will be capable of storing 45 kJ of mechanical energy with a peak operating speed of 5,000 rpm at 190 V. Theoretical calculations resulted in the following predicted electrical performance values: a peak output …

Isogeometric Fluid–Structure Interaction Analysis With Emphasis On Non-Matching Discretizations, And With Application To Wind Turbines, Y. Bazilevs, Ming-Chen Hsu, M. A. Scott

Ming-Chen Hsu

In this paper we develop a framework for fluid–structure interaction (FSI) modeling and simulation with emphasis on isogeometric analysis (IGA) and non-matching fluid–structure interface discretizations. We take the augmented Lagrangian approach to FSI as a point of departure. Here the Lagrange multiplier field is defined on the fluid–structure interface and is responsible for coupling of the two subsystems. Thus the FSI formulation does not rely on the continuity of the underlying function spaces across the fluid–structure interface in order to produce the correct coupling conditions between the fluid and structural subdomains. However, in deriving the final FSI formulation the interface …

Loss Enhanced Transmission And Collimation In Anisotropic Epsilon-Near-Zero Metamaterials, L. Sun, S. Feng, Xiaodong Yang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

We verify the extraordinary transmission enhancement and collimation induced by the material loss in anisotropic epsilon-near-zero metamaterials, and reveal the physical mechanism of this exotic electromagnetic phenomenon via the iso-frequency contour analysis. In addition, we demonstrate the possibility in realization of such loss enhanced transmission of Gaussian beam in realistic silver-germanium multilayered structures by applying full-wave numerical simulations.

Implementation Of Microwave Transmissions For Rocket Exhaust Plume Diagnostics, Nicholas George Coutu

Doctoral Dissertations and Master's Theses

Rocket-launched vehicles produce a trail of exhaust that contains ions, free electrons, and soot. The exhaust plume increases the effective conductor length of the rocket. A conductor in the presence of an electric field (e.g. near the electric charge stored within a cloud) can channel an electric discharge. The electrical conductivity of the exhaust plume is related to its concentration of free electrons. The risk of a lightning strike in-flight is a function of both the conductivity of the body and its effective length. This paper presents an approach that relates the electron number density of the exhaust plume to …

Novel Airframe Design For The Dual-Aircraft Atmospheric Platform Flight Concept, Eric Michael Mckee

Doctoral Dissertations and Master's Theses

A high-altitude, long-endurance unmanned aerial airframe was designed for the innovative Dual-Aircraft Atmospheric Platform flight concept that exploits stratospheric wind velocity gradients to remain aloft indefinitely. Classical aircraft preliminary design techniques and high-fidelity tools were used to establish a baseline configuration.

Performance characteristics of numerous airfoil profiles were evaluated with two-dimensional flow software in an effort to determine the best-candidate airfoil for the unique application. Vortex-Lattice method tools were used to investigate the sensitivity of three-dimensional design parameters upon overall vehicle aerodynamic performance and determine both static and dynamic stability characteristics of the airframe. Performance capabilities of the finalized airframe …

Distributed Forcing On A 3d Bluff Body With A Blunt Base, An Experimental Active Drag Control Approach, Ethan Bruce Erlhoff

Master's Theses

This paper seeks to explore the effects of an active drag control method known as distributed forcing on a 3D bluff body with a blunt base. The 9.5 x 15.25 x 3 inch aluminum model constructed for this experiment has an elliptically shaped nose and rectangular aft section. The model is fitted with four, 12 Volt fans, forcing the freestream air into and out of 1 mm thick slots on the upper and lower trailing edges. The forcing is steady in time, held at a constant forcing velocity though all Reynolds numbers, but varies roughly sinusoidally in the spanwise direction …

Closed-Loop Thrust And Pressure Profile Throttling Of A Nitrous Oxide/Hydroxyl-Terminated Polybutadiene Hybrid Rocket Motor, Zachary W. Peterson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Hybrid motors that employ non-toxic, non-explosive components with a liquid oxidizer and a solid hydrocarbon fuel grain have inherently safe operating characteristics. The inherent safety of hybrid rocket motors offers the potential to greatly reduce overall operating costs. Another key advantage of hybrid rocket motors is the potential for in-flight shutdown, restart, and throttle by controlling the pressure drop between the oxidizer tank and the injector. This research designed, developed, and ground tested a closed-loop throttle controller for a hybrid rocket motor using nitrous oxide and hydroxyl-terminated polybutadiene as propellants. The research simultaneously developed closed-loop throttle algorithms and lab scale …

Space Vehicle Testing, Charlotte Ann Belsick

Master's Theses

Requirement verification and validation is a critical component of building and delivering space vehicles with testing as the preferred method. This Master’s Project presents the space vehicle test process from planning through test design and execution. It starts with an overview of the requirements, validation, and verification. The four different verification methods are explained including examples as to what can go wrong if the verification is done incorrectly. Since the focus of this project is on test, test verification is emphasized. The philosophy behind testing, including the “why” and the methods, is presented. The different levels of testing, the test …

Heat Transfer Analysis Via Rate Based Sensors, Jake Erik Plewa

Masters Theses

This work presents an integrated rate-based sensor and method for resolving the surface heat flux of a fundamental inverse heat conduction problem without numerical regularization or differentiation in a semi-infinite geometry that additionally accounts for thermocouple delay due to its intrinsic time constant. The sensor uses well-designed analog filters to directly regularize raw voltage data to eliminate the need for numerical regularization methods. The sensor can also be used in a series of well-designed voltage-rate interfaces that directly measure the voltages from in-depth thermocouples, which are used in conjunction with the thermocouple calibration curve to provide higher-time derivatives of the …

Confined Mixing Of Multiple Transverse Jets, Allen J. Bishop

Master's Theses

The mixing performance of multiple transverse jets has been evaluated experimentally. Measurement techniques included laser Doppler velocimetry and planar laser induced fluorescence. Basic findings are consistent with results presented in literature for single jet mixing behavior. Mixing performance has been compared to literature for the single jet case and the Holdeman parameter has been re-evaluated for effectiveness at low jet numbers. A single jet in a confined crossflow was found to have a local minimum at B(d⁄D) = 0.721. Results for two jets indicate monotonically decreasing unmixedness for the range of conditions tested, with no local optimum apparent. Data for …

Effects Of Seawater On The Mechanical Behavior Of Composite Sandwich Panels Under Monotonic Shear Loading, Thomas Robert Woo

Master's Theses

Abstract

Salt water environments are very harsh on materials that are used within them. Many issues are caused by either corrosion and/or internal degradation to the materials themselves. Composites are better suited for this environment due to their high strength to weight ratios and their corrosion resistance, but very little is known about the fracture mechanics of composites. The goal of this study is to gain a better understanding for the behavior of a composite boat hull under a shear loading, similar to the force water applies on the hull as the boat moves through the water; then attempt to …

Calibration And Characterization Of Cubesat Magnetic Sensors Using A Helmholtz Cage, Justin Dean Foley

Master's Theses

Small satellites, and CubeSats in particular, have quickly become a hot topic in the aerospace industry. Attitude determination is currently one of the most intense areas of development for these miniaturized systems and future Cal Poly satellite missions will depend heavily on magnetometers. In order to utilize magnetometers as a viable source of attitude knowledge, precise calibration is required to ensure the greatest accuracy achievable. This paper outlines a procedure for calibrating and testing magnetometers on the next generation of Cal Poly CubeSates, utilizing a Helmholtz cage to simulate any desired orbital magnetic field that would be experienced by a …

The Application Of Systems Engineering Principles To Model Lithium Ion Battery Voltage, George Gibbs

Master's Theses

The objective of this project is to present a Lithium Ion battery voltage model derived using systems engineering principles. This paper will describe the details of the model and the implementation of the model in practical use in a power system. Additionally, the model code is described and results of the model output are compared to battery cell test data. Finally, recommendations for increased model fidelity and capability are summarized.

The modeling theory has been previously documented in the literature but detailed implementation and application of the modeling theory is shown. The detailed battery cell test voltage profiles are proprietary; …

Aerodynamic Analysis And Drag Coefficient Evaluation Of Time-Trial Bicycle Riders, Peter Nicholas Doval

Theses and Dissertations

Evaluation of drag coefficient often requires wind tunnel experiments and can be prohibitively expensive if not impossible for large objects or systems. Computational Fluid Dynamics (CFD) aerodynamic analysis offers an alternative approach and can be used as a very effective design tool in many industries: automotive, aerospace, marine, etc. The main objective of this research is to investigate feasibility of using non-contact digitizers for developing finite element models of large objects for subsequent CFD analysis. The developed methodology is applied to investigation of time-trial bicycle rider efficiency. Companies competing in this class of racing spend millions trying to optimize bicycle …

Stochastic Optimal Control In Nonlinear Systems, Celestin Nkundineza

Celestin Nkundineza

Stochastic control is an important area of research in engineering systems that undergo disturbances. Controlling individual states in such systems is critical. The present investigation is concerned with the application of the stochastic optimal control strategy developed by To (2010) and its implementation as well as providing computed results of linear and nonlinear systems under stationary and nonstationary random excitations. In the strategy the feedback matrix is designed based on the achievement of the objectives for individual states in the system through the application of the Lyapunov equation for the system. Each diagonal element in the gain or associated gain …

Structural Damage Assessment Of Propulsions System Components By Impedance Based Health Monitoring, Richard Martin, Andrew Gyekneyesi, Jerzy Sawicki, George Baaklini

Jerzy T. Sawicki

No abstract provided.

High Temperature Fusion Reactor Cooling Using Brayton Cycle Based Partial Energy Conversion, Albert Juhasz, Jerzy Sawicki

Jerzy T. Sawicki

For some future space power systems using high temperature nuclear heat sources most of the output energy will be used in other than electrical form, and only a fraction of the total thermal energy generated will need to be converted to electrical work. The paper describes the conceptual design of such a “partial energy conversion” system, consisting of a high temperature fusion reactor operating in series with a high temperature radiator and in parallel with dual closed cycle gas turbine (CCGT) power systems, also referred to as closed Brayton cycle (CBC) systems, which are supplied with a fraction of the …

Manufacturing Processes In An All-Aluminum Airframe, Stewart Mcdougall

Aerospace Engineering

One often overlooked aspect to building an aircraft is the manufacturing process used to put it into production. This may be a major contributor to acquisition cost and requires a large amount of money to implement. Once all the tooling has been purchased, one of the greatest costs is labor. The experience of building an all-aluminum aircraft shows that the production process is one which may be done in many different ways. Minimizing the assembly time is important for aircraft manufacturers and one of the best ways to do that is on the assembly line itself. Specific practices in the …

A Gap Analysis Of Meteorological Requirements For Commercial Space Operators, Nicholas Stapleton

Doctoral Dissertations and Master's Theses

Commercial space companies will soon be the primary method of launching people and supplies into orbit. Among the critical aspects of space launches are the meteorological concerns. Laws and regulations pertaining to meteorological considerations have been created to ensure the safety of the space industry and those living around spaceports; but, are they adequate? Perhaps the commercial space industry can turn to the commercial aviation industry to help answer that question. Throughout its history, the aviation industry has dealt with lessons learned from mishaps due to failures in understanding the significance of weather impacts on operations. Using lessons from the …

Determination Of Human Powered Helicopter Stability Characteristics Using Multi-Body System Simulation Techniques, Sean M. Brown

Master's Theses

Multi-Body System Simulation combined with System Identification was developed as a method for determining the stability characteristics of a human powered helicopter(HPH) configurations. HPH stability remains a key component for meeting competition requirements, but has not been properly treated. Traditional helicopter dynamic analysis is not suited to the HPH due to its low rotation speeds and light weight. Multi-Body System Simulation is able to generate dynamic response data for any HPH configuration. System identification and linear stability theory are used to determine the stability characteristics from the dynamic response. This thesis focuses on the method development and doesn't present any …

Mechanical Optimization And Buckling Analysis Of Bio-Composites, Cameron D. Chan

Master's Theses

Today’s environmental concerns have led a renewed search in industry to find new sustainable materials to replace non-renewable resources. President Barack Obama also quoted in the recent 2012 Presidential Debate “that there is a need to build the energy sources of the future and invest in solar, wind, and bio-fuels.” Bio-composites are believed to be the future and the new substitute for non-renewable resources. Bio-composites are similar to composites in that they are made up of two constituent materials; however the main difference is that bio-composites are made from natural fibers and a biopolymer matrix. This research investigates the buckling …

Optimizing The Mechanical Characteristics Of Bamboo To Improve The Flexural Behavior For Biocomposite Structural Application, Jay Lopez

Master's Theses

Global awareness and preservation have spurred increasing interest in utilizing environmentally friendly materials for high-performance structural applications. Biocomposites pose an appealing solution to this issue and are characterized by their sustainable lifecycles, biodegradable qualities, light weight, remarkable strength, and exceptional stiffness. Many of these structural qualities are found in applications that exhibit flexural loading conditions, and this study focuses on improving the bending performance of engineered biocomposite structures. The current application of biocomposites is increasing rapidly, so this expanding research explores other natural constituent materials for biocomposite structures under flexural loading.

The renewable material investigated in this study was experimentally …

Review Of The Challenger Launch Decision: Risky Technology, Culture And Deviance At Nasa, Peter F. Meiksins

Peter Meiksins

Reviews the book "The Challenger Launch Decision: Risky Technology, Culture and Deviance at NASA," by Diane Vaughan.