Drag Reduction Utilizing Driven Micro-Cavities,
2016
Missouri University of Science and Technology
Drag Reduction Utilizing Driven Micro-Cavities, David W. Riggins
Mechanical and Aerospace Engineering Faculty Research & Creative Works
A high-speed vehicle or device presents a surface configured to move through a fluid such that the fluid flows across the surface in a primary flow direction. The vehicle or device also presents a subsurface spaced inwardly from the surface, as well as a plurality of cavity-defining structures that project generally outwardly from the subsurface and extend along the subsurface generally transverse to the primary flow direction. The cavity-defining structures are spaced apart in the primary flow direction. Each adjacent pair of the cavity-defining structures and the subsurface at least in part cooperatively define a cavity therebetween. Fluid rollers or …
Preliminary Design Tools In Turbomachinery: Non-Uniformly Spaced Blade Rows, Multistage Interaction, Unsteady Radial Waves, And Propeller Horizontal-Axis Turbine Optimization,
2016
Purdue University
Preliminary Design Tools In Turbomachinery: Non-Uniformly Spaced Blade Rows, Multistage Interaction, Unsteady Radial Waves, And Propeller Horizontal-Axis Turbine Optimization, Yujun Leng
Open Access Dissertations
Turbomachinery flow fields are inherently unsteady and complex which makes the related CFD analyses computationally intensive. Physically based preliminary design tools are desirable for parametric studies early in the design stage, and to provide deep physical insight and a good starting point for the later CFD analyses. Four analytical/semi-analytical models are developed in this study: 1) a generalized flat plate cascade model for investigating the unsteady aerodynamics of a blade row with non-uniformly spaced blades; 2) a multistage interaction model for investigating rotor-stator interactions; 3) an analytical solution for quantifying the impeller wake convection and pressure wave propagating between a …
Utilization Of Trss To Assist Pilot’S Decision Making Process During Critical Runway Operations.,
2016
Minnesota State University, Mankato
Utilization Of Trss To Assist Pilot’S Decision Making Process During Critical Runway Operations., Nihad E. Daidzic
Aviation Department Publications
No abstract provided.
Incorporation Of Gnss Multipath To Improve Autonomous Rendezvous, Docking And Proximity Operations In Space,
2016
Purdue University
Incorporation Of Gnss Multipath To Improve Autonomous Rendezvous, Docking And Proximity Operations In Space, Benjamin W. Ashman
Open Access Dissertations
Automated rendezvous and docking (AR&D;) operations are important for many future space missions, such as the resupply of space stations, repair and refueling of large satellites, and active removal of orbital debris. These operations depend critically on accurate, real-time knowledge of the relative position and velocity between two space vehicles. Unfortunately, Global Navigation Satellite System (GNSS) capabilities remain severely limited in close proximity to large space structures due to significant multipath effects and signal blockage. Although GNSS is used for the initial stages of approach, other instruments such as laser, radar and vision-based systems, are required to augment GNSS during …
Transfers To A Gravitational Saddle Point: An Extended Mission Design Option For Lisa Pathfinder,
2016
Purdue University
Transfers To A Gravitational Saddle Point: An Extended Mission Design Option For Lisa Pathfinder, Andrew D. Cox
Open Access Theses
Any possible LISA Pathfinder extended mission will immediately follow the primary mission after completion of scientific observations and technical demonstrations in a Sun-Earth L1 libration point orbit. One extended mission concept with scientific appeal is a spacecraft path that includes multiple encounters with a gravitational equilibrium point. This point, also termed a saddle point, exists where the total gravitational acceleration sums to zero and is distinct from the five Lagrange points in the three-body problem. This investigation seeks a strategy to design such a path subject to a variety of constraints. Periodic, quasi-periodic, and manifold structures are explored to …
Phase Of Flight Identification In General Aviation Operations,
2016
Purdue University
Phase Of Flight Identification In General Aviation Operations, Valentine Pascale Goblet
Open Access Theses
Identifying phases of flight in General Aviation can help in identifying safety events, which are events which may result in the aircraft being in a hazardous state. Unlike commercial operations that have well-defined phases of flight such as taxi, takeoff, climb, cruise, descent, approach, and landing, GA missions have more hard-to-identify phases of flight. For example, pilot training missions can involve multiple “touch-and-go” maneuvers, which make it difficult to define a distinct cruise phase during the patterns. Here, we present an algorithm to automatically identifying phases of flight in GA. The method includes an algorithm to tailor the phase of …
Dynamic Sensor Tasking And Imm Ekf Estimation For Tracking Impulsively Maneuvering Satellites,
2016
Purdue University
Dynamic Sensor Tasking And Imm Ekf Estimation For Tracking Impulsively Maneuvering Satellites, Arthur A. Lace
Open Access Theses
In order to efficiently maintain space situational awareness, care must be taken to optimally allocate expensive observation resources. In most situations the available sensors capable of tracking spacecraft have their time split between many different monitoring responsibilities. Tracking maneuvering spacecraft can be especially difficult as the schedule of maneuvers may not be known and will often throw off previous orbital models. Effectively solving this tasking problem is an ongoing focus of research in the area of space situational awareness. Most methods of automated tasking do not make use of interacting multiple model extended Kalman filter techniques to better track satellites …
An Experimental Comparison Of Diffuser Designs In A Centrifugal Compressor,
2016
Purdue University
An Experimental Comparison Of Diffuser Designs In A Centrifugal Compressor, Cam-Tu Jeanne Methel
Open Access Theses
The objective of this investigation was to compare the effects of two different diffuser vane geometries on the performance of a centrifugal compressor. Vaned diffusers are commonly used in aeroengines because they can achieve higher pressure recoveries than vaneless diffusers of similar size. Improving the diffuser’s pressure recovery and effectiveness can result in overall compressor performance benefits that are sought out by engine manufacturers looking to improve overall engine efficiency. An airfoil vane was tested and compared to a baseline wedge diffuser in the Purdue CSTAR research facility, where the centrifugal compressor used for this study is intended to be …
Unsupervised Learning Framework For Large-Scale Flight Data Analysis Of Cockpit Human Machine Interaction Issues,
2016
Purdue University
Unsupervised Learning Framework For Large-Scale Flight Data Analysis Of Cockpit Human Machine Interaction Issues, Abhishek B. Vaidya
Open Access Theses
As the level of automation within an aircraft increases, the interactions between the pilot and autopilot play a crucial role in its proper operation. Issues with human machine interactions (HMI) have been cited as one of the main causes behind many aviation accidents. Due to the complexity of such interactions, it is challenging to identify all possible situations and develop the necessary contingencies. In this thesis, we propose a data-driven analysis tool to identify potential HMI issues in large-scale Flight Operational Quality Assurance (FOQA) dataset. The proposed tool is developed using a multi-level clustering framework, where a set of basic …
Tadpole Orbits In The L4/L5 Region: Construction And Links To Other Families Of Periodic Orbits,
2016
Purdue University
Tadpole Orbits In The L4/L5 Region: Construction And Links To Other Families Of Periodic Orbits, Alexandre G. Van Anderlecht
Open Access Theses
The equations of motion in the Circular Restricted Three-Body Problem (CR3BP) allow five equilibrium solutions, that is, the Lagrange or libration points. Two of the five equilibrium solutions are the triangular or equilateral libration points, L4 and L 5. As the secondary gravitational body moves in its orbit about the larger mass, L4 and L5 lead and trail the secondary by 60 degrees, respectively. This investigation focuses on periodic solutions in the vicinity of the triangular libration points, specifically horseshoe and tadpole orbits. Horseshoe orbits are symmetric periodic solutions in the plane of primary motion encompassing both …
A Transfer Network Linking Earth, Moon, And The Triangular Libration Point Regions In The Earth-Moon System,
2016
Purdue University
A Transfer Network Linking Earth, Moon, And The Triangular Libration Point Regions In The Earth-Moon System, Lucia R. Capdevila
Open Access Dissertations
In the near future, several space applications in the Earth-Moon system may require a spacecraft to hold a stable motion, but the transfer trajectory infrastructure to access such stable motions has not been fully investigated yet. The triangular libration points, L 4and L5, in the Earth-Moon system have long been thought of as ideal locations for a communications satellite. Recently, Distant Retrograde Orbits (DROs) and Near-Rectilinear Halo Orbits (NRHOs) near the Moon have been identified as motion of interest for manned and unmanned missions with a focus on operations in cislunar space. The triangular libration points, as well as …
Coupled Orbit-Attitude Mission Design In The Circular Restricted Three-Body Problem,
2016
Purdue University
Coupled Orbit-Attitude Mission Design In The Circular Restricted Three-Body Problem, Davide Guzzetti
Open Access Dissertations
Trajectory design increasingly leverages multi-body dynamical structures that are based on an understanding of various types of orbits in the Circular Restricted Three-Body Problem (CR3BP). Given the more complex dynamical environment, mission applications may also benefit from deeper insight into the attitude motion. In this investigation, the attitude dynamics are coupled with the trajectories in the CR3BP. In a highly sensitive dynamical model, such as the orbit-attitude CR3BP, periodic solutions allow delineation of the fundamental dynamical structures. Periodic solutions are also a subset of motions that are bounded over an infinite time-span (assuming no perturbing factors), without the necessity to …
Examining American Attitudes On The Use Of Military Drones,
2016
Bemidji State University
Examining American Attitudes On The Use Of Military Drones, Todd Brandon
Political Science Theses and Capstones
Recent polls have revealed that Americans of both the political left and right support the use of military drones. This statement stands true among groups who traditionally do not support the use of military force. I hypothesize that people of a more liberal persuasion will be more concerned with whether or not the drone program endangers innocent civilians, while those of a more conservative view will be more concerned with the legality of conducting military drone strikes. I analyze data obtained from the Pew Research Center to examine people's attitudes on military drone strikes via framing theory. My hypothesis has …
Effects Of Curing Cycle And Loading Rates On The Bearing Stress Of Double Shear Composite Joints,
2016
California Polytechnic State University, San Luis Obispo
Effects Of Curing Cycle And Loading Rates On The Bearing Stress Of Double Shear Composite Joints, Mateja Andrejic
Master's Theses
In the last few decades, there has been a shift to using more lightweight materials for the potential of fuel consumption reduction. In the Aerospace Industry, conventional metal structures are being replaced by advanced composite structures. The major advantage of an advanced composite structure is the huge reduction in the number of parts and joints required. Also composite materials provide better resistance to creep, corrosion, and fatigue. However, one cannot eliminate all the joints and attachments in an aircraft’s structure. Eliminating structural joints is impractical in present-day aircraft because of the requirements for inspection, manufacturing breaks, assembly and equipment access, …
Syllabus: Space Systems Engineering 122 (Satellites And Space Systems Ii),
2016
Morehead State University
Syllabus: Space Systems Engineering 122 (Satellites And Space Systems Ii), Robert J. Twiggs
Robert "Bob" Twiggs STEM Education Collection
A syllabus created by Professor Bob Twiggs for Space Systems Engineering 122 (Satellites and Space Systems II) taught at Morehead State University in the Spring of 2016.
Nonlinear Analysis Of Balance Data In The Easter Seals Adult Day Services Population,
2016
University of Dayton
Nonlinear Analysis Of Balance Data In The Easter Seals Adult Day Services Population, Taylor Marie Schemmel
Honors Theses
81.1 million adults are expected to be affected by dementia in 2040. Individuals with dementia are twice as likely to fall as healthy individuals and three times as likely to sustain an injury during a fall. Unfortunately, current fall prevention techniques in place for cognitively healthy older adults are not as effective for those with dementia. The objective of this study was to examine balance differences between individuals of varying cognitive ability utilizing Easter Seals Adult Day Services. All study participants completed the Montreal Cognitive Assessment (MoCA). Clinical assessments were done in conjunction with static posturography data collection on a …
A Hybrid Position Feedback Controller For Bistable Structures,
2016
Old Dominion University
A Hybrid Position Feedback Controller For Bistable Structures, Mehmet R. Simsek
Mechanical & Aerospace Engineering Theses & Dissertations
Bistability is the property of structures showing the ability to attain two statically stable states. Due to dynamic and static advantages such as no energy demand at stable positions and providing higher deflections compared to a monostable structure, bistability may be appealing in control surface design for aircraft structures and load alleviation for wind turbine blades. The dynamics of bistable structures is nonlinear because of the snap-through occurring during the cross-well oscillation between two stable states. A new control strategy called hybrid position feedback control is developed based on the conventional positive position control to exploit linear dynamics of bistable …
Experimental Analysis Of Turbulent Structures And The Effects Of Non-Equilibrium On An Axial Vortex,
2016
Old Dominion University
Experimental Analysis Of Turbulent Structures And The Effects Of Non-Equilibrium On An Axial Vortex, Michael P. Thompson
Mechanical & Aerospace Engineering Theses & Dissertations
Examples of the axial vortex include, dust devils, trailing line aircraft wake vortices, and tornadoes. Some of these vortices can prove hazardous to individuals and property. This necessitates that studies be conducted to understand their structure and to attempt to develop mathematical models of the flow physics involved. A wide variety of experimental techniques have been used in the past to study the vortex, with flow visualization and hotwire anemometry being chosen for this experiment. There have been many inadequate mathematical models proposed in the past. The experimental results obtained were compared to the work of Ash, Zardadkhan and Zuckerwar …
The Decomposition Of Hydroxylammonium Nitrate Under Vacuum Conditions,
2016
Western Michigan University
The Decomposition Of Hydroxylammonium Nitrate Under Vacuum Conditions, Gregory A. Neff
Masters Theses
This research investigates the decomposition of the ionic liquid: hydroxylammonium nitrate (HAN), under vacuum conditions. All research was conducted at the Aerospace Laboratory for Plasma Experiments (ALPE) at Western Michigan University. Hydroxylammonium nitrate solution 24% wt. in H2O was used consistently throughout this research. A variety of temperatures and pressures ranging from 23°C to 645°C and 6E-3 Torr to 4 Torr, respectively, were used to decompose HAN. The primary gaseous species resulting from these decomposition conditions are N2O, NO, and trace amounts of NO2. The formation of H2O, and N2 is conditional on the experimental conditions, and the formation of …
A Hybrid Vortex Solution For Surge Margin Enhancement In Axial Compressors,
2016
Embry-Riddle Aeronautical University
A Hybrid Vortex Solution For Surge Margin Enhancement In Axial Compressors, Daniel Port
Doctoral Dissertations and Master's Theses
A new vortex solution to the Simple Radial Equilibrium Equation (SREE) is presented that incorporates endwall effects into the preliminary design stage of a single stage, low pressure compressor with a hub-to-tip ratio of 0.4 and non-axial inlet flow. This vortex solution is proposed to overcome the rapidly approaching asymptotic peak in compressor performance in the industry today. The Hybrid Vortex theory incorporates a versatile, higher-order solution to the SREE, resulting in more accurate preliminary designs requiring less manipulation in the final design stages. This new solution results in significant changes in hub geometry with the stagger of the hub …
