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Numerical And Experimental Study On The Ability Of Dynamic Roughness To Alter The Development Of A Leading Edge Vortex, Christopher D. Griffin
Numerical And Experimental Study On The Ability Of Dynamic Roughness To Alter The Development Of A Leading Edge Vortex, Christopher D. Griffin
Graduate Theses, Dissertations, and Problem Reports
Dynamic stall is an unsteady aerodynamic phenomenon garnering much research interest because it occurs in a variety of applications. For example, dynamic stall is known to occur on helicopter rotor blades, wind turbines, high maneuvering military aircraft, and flapping wings. Dynamic stall occurs when an aerodynamic lifting device, such as an airfoil, wing, or turbomachine blade, undergoes a rapid pitching motion. It also occurs on lifting devices that are impulsively started at high angles of attack. Dynamic stall can "delay" aerodynamic stall to angles of attack that are significantly beyond the static stall angle of attack.;During dynamic stall a large …
Machine-Vision-Based Pose Estimation System Using Sensor Fusion For Autonomous Satellite Grappling, Andres Felipe Velasquez Escandon
Machine-Vision-Based Pose Estimation System Using Sensor Fusion For Autonomous Satellite Grappling, Andres Felipe Velasquez Escandon
Graduate Theses, Dissertations, and Problem Reports
When capturing a non-cooperative satellite during an on-orbit satellite servicing mission, the position and orientation (pose) of the satellite with respect to the servicing vessel is required in order to guide the robotic arm of the vessel towards the satellite. The main objective of this research is the development of a machine vision-based pose estimation system for capturing a non-cooperative satellite. The proposed system finds the satellite pose using three types of natural geometric features: circles, lines and points, and it merges data from two monocular cameras and three different algorithms (one for each type of geometric feature) to increase …
Folding Solid-Membrane Wing Structure For A Micro Air Vehicle, Joe D. Allen Jr.
Folding Solid-Membrane Wing Structure For A Micro Air Vehicle, Joe D. Allen Jr.
Graduate Theses, Dissertations, and Problem Reports
The design of a solid-membrane folding wing for use on a tube launched micro air vehicle (MAV), and experimental wind tunnel results of the wing integrated on an engineering MAV model are presented herein. Due to the sizing and performance requirements of the MAV, the wing must provide sufficient wing area while minimizing its stowed footprint. Many current available methods for folding the wing for such a MAV sacrifice aerodynamic efficiency or are cost prohibitive. The solid-membrane wing design presented blends elements of a solid semi-rigid wing with those of a membrane wing. This provides the aerodynamic efficiency of a …
Wind And Wake Sensing With Uav Formation Flight: System Development And Flight Testing, Trenton Jameson Larrabee
Wind And Wake Sensing With Uav Formation Flight: System Development And Flight Testing, Trenton Jameson Larrabee
Graduate Theses, Dissertations, and Problem Reports
Wind turbulence including atmospheric turbulence and wake turbulence have been widely investigated; however, only recently it become possible to use Unmanned Aerial Vehicles (UAVs) as a validation tool for research in this area. Wind can be a major contributing factor of adverse weather for aircraft. More importantly, it is an even greater risk towards UAVs because of their small size and weight. Being able to estimate wind fields and gusts can potentially provide substantial benefits for both unmanned and manned aviation. Possible applications include gust suppression for improving handling qualities, a better warning system for high wind encounters, and enhanced …
Aerodynamic Parameter Identification Of A Venus Lander, Robert A. Sykes
Aerodynamic Parameter Identification Of A Venus Lander, Robert A. Sykes
Graduate Theses, Dissertations, and Problem Reports
An analysis was conducted to identify the parameters of an aerodynamic model for a Venus lander based on experimental free-flight data. The experimental free-flight data were collected in the NASA Langley 20-ft Vertical Spin Tunnel with a 25-percent Froude-scaled model. The experimental data were classified based on the wind tunnel run type: runs where the lander model was unperturbed over the course of the run, and runs were the model was perturbed (principally in pitch, yaw, and roll) by the wind tunnel operator. The perturbations allow for data to be obtained at higher wind angles and rotation rates than those …
Droplet Impact Sub-Cavity Histories And Pdpa Spray Experiments For Spray Cooling Modeling, Nicholas Lee Hillen
Droplet Impact Sub-Cavity Histories And Pdpa Spray Experiments For Spray Cooling Modeling, Nicholas Lee Hillen
Graduate Theses, Dissertations, and Problem Reports
Spray cooling is a topic of current interest for its ability to uniformly remove high levels of waste heat from densely packed microelectronics. It has demonstrated the ability to achieve very high heat fluxes, up to 500 W/cm2 with water as the coolant, making it an attractive active thermal management tool.;Full Computational Fluid Dynamic (CFD) simulations of spray cooling are infeasible due to the complexity of the spray (drops fluxes of 106 drops/cm2-sec) and heater surface physics requiring impractical resources. Thus a Monte-Carlo (MC) spray cooling simulation model based on empirical data is under development to serve as a cost …
Sensitivity And Stability Analysis Of Nonlinear Kalman Filters With Application To Aircraft Attitude Estimation, Matthew Brandon Rhudy
Sensitivity And Stability Analysis Of Nonlinear Kalman Filters With Application To Aircraft Attitude Estimation, Matthew Brandon Rhudy
Graduate Theses, Dissertations, and Problem Reports
No abstract provided.
Development Of An Integrated Intelligent Multi -Objective Framework For Uav Trajectory Generation, Jennifer Nicole Wilburn
Development Of An Integrated Intelligent Multi -Objective Framework For Uav Trajectory Generation, Jennifer Nicole Wilburn
Graduate Theses, Dissertations, and Problem Reports
This thesis explores a variety of path planning and trajectory generation schemes intended for small, fixed-wing Unmanned Aerial Vehicles. Throughout this analysis, discrete and pose-based methods are investigated. Pose-based methods are the focus of this research due to their increased flexibility and typically lower computational overhead.;Path planning in 3 dimensions is also performed. The 3D Dubins methodology presented is an extension of a previously suggested approach and addresses both the mathematical formulation of the methodology, as well as an assessment of numerical issues encountered and the solutions implemented for these.;The main contribution of this thesis is a 3-dimensional clothoid trajectory …
Aerodynamics Investigation Of Faceted Airfoils At Low Reynolds Number, Zachary G. Napolillo
Aerodynamics Investigation Of Faceted Airfoils At Low Reynolds Number, Zachary G. Napolillo
Graduate Theses, Dissertations, and Problem Reports
The desire and demand to fly farther and faster has progressively integrated the concept of optimization with airfoil design, resulting in increasingly complex numerical tools pursuing efficiency often at diminishing returns; while the costs and difficulty associated with fabrication increases with design complexity. Such efficiencies may often be necessary due to the power density limitations of certain aircraft such as small unmanned aerial vehicles (UAVs) and micro air vehicles (MAVs).;This research, however, focuses on reducing the complexity of airfoils for applications where aerodynamic performance is less important than the efficiency of manufacturing; in this case a Hybrid Projectile. By employing …
Analysis Of Gps Abnormal Conditions Within Fault Tolerant Control Laws, Gahssan Al-Sinbol
Analysis Of Gps Abnormal Conditions Within Fault Tolerant Control Laws, Gahssan Al-Sinbol
Graduate Theses, Dissertations, and Problem Reports
The Global Position System (GPS) is a critical element for the functionality of autonomous flying vehicles. The GPS operation at normal and abnormal conditions directly impacts the trajectory tracking performance of the autonomous Unmanned Aerial Vehicles (UAVs) controllers. The effects of GPS parameter variation must be well understood and user-friendly computational tools must be developed to facilitate the design and evaluation of fault tolerant control laws.;This thesis presents the development of a simplified GPS error model in Matlab/Simulink and its use performing a sensitivity analysis of GPS parameters effect under system normal and abnormal operation on different UAV trajectory tracking …
Hybrid Projectile Body Angle Estimation For Selectable Range Increase, Christopher J. Gioia
Hybrid Projectile Body Angle Estimation For Selectable Range Increase, Christopher J. Gioia
Graduate Theses, Dissertations, and Problem Reports
A Hybrid Projectile (HP) is a tube launched munition that transforms into a gliding UAV, and is currently being researched at West Virginia University. A simple launch timer was first envisioned to control the transformation point in order to achieve maximum distance. However, this timer would need to be reprogrammed for any distance less than maximum range due to the nominal time to deployment varying with launch angle. A method was sought for automatic wing deployment that would not require reprogramming the round. A body angle estimation system was used to estimate the pitch of the HP relative to the …
Tuning The Electrical And Thermal Conductivities Of Thermoelectric Oxides Through Impurity Doping, Maria A. Torres Arango
Tuning The Electrical And Thermal Conductivities Of Thermoelectric Oxides Through Impurity Doping, Maria A. Torres Arango
Graduate Theses, Dissertations, and Problem Reports
Waste heat and thermal gradients available at power plants can be harvested to power wireless networks and sensors by using thermoelectric (TE) generators that directly transform temperature differentials into electrical power. Oxide materials are promising for TE applications in harsh industrial environments for waste heat recovery at high temperatures in air, because they are lightweight, cheaply produced, highly efficient, and stable at high temperatures in air. Ca3Co4O9(CCO) with layered structure is a promising p-type thermoelectric oxide with extrapolated ZT value of 0.87 in single crystal form [1]. However the ZT values for the polycrystalline ceramics remain low of ∼0.1-0.3. In …