A Microresonator-Based Laser Doppler Velocity Sensor For Interplanetary Atmospheric Re-Entry,
2018
Southern Methodist University
A Microresonator-Based Laser Doppler Velocity Sensor For Interplanetary Atmospheric Re-Entry, Benjamin Wise
Mechanical Engineering Research Theses and Dissertations
In this thesis, a laser velocity sensor concept based on optical microresonators is presented and the application to spacecraft atmospheric entry is explored. The concept is based on the measurement of Doppler shift of back-scattered laser light. Specifically, the Doppler shift is detected by observing the whispering gallery optical modes (WGM) of a dielectric microresonator excited by the back scattered light from particulates and gas molecules. The microresonator replaces the typical Fabry-Perot interferometer and CCD camera system, thereby significantly reducing the size and weight of the overall detection system. This thesis presents proof-of-concept results for this measurement approach. The Doppler …
Validation Of Cfd Simulations For Hypersonic Flow Over A Yawed Cone,
2018
Washington University in St. Louis
Validation Of Cfd Simulations For Hypersonic Flow Over A Yawed Cone, Julian Cecil
McKelvey School of Engineering Graduate Student Theses & Dissertations
This study aims to numerically simulate the wind tunnel results for hypersonic flow over a circular cone of semi-apex angle of 10 degrees yawed from 0° to 20° using the commercial computational fluid dynamics software ANSYS Fluent. The ANSYS workbench is used to create the 10° semi-apex circular cone with a shock aligned structured mesh of 3.05 million cells surrounding the cone. Simulation boundary conditions for pressure and temperature in the far field correspond to Tracy’s wind tunnel experiment at Cal Tech. The six simulations cases are conducted for yaw angles of 0, 8, 12, 16, 20 and 24 degrees. …
The Drag Coefficient Of Varying Dimple Patterns,
2018
Linfield College
The Drag Coefficient Of Varying Dimple Patterns, James M. Seeley, Michael S. Crosser
Senior Theses
There are many golf balls on the market today with varying dimple sizes, shapes, and distribution. These proprietary differences are all designed to reduce drag on the balls during flight, allowing golfers to hit the ball farther distances. There are limited published studies comparing how varying the dimples affects the reduction of drag. An experiment was developed in which golf balls were pulled through a water tank to measure the drag force acting on each ball. The water was chosen to allow for testing at slower velocities than the typical necessary speeds to cause turbulence for balls traveling in air. …
Measurement Of Forces On A Flapping Wing Micro Aerial Vehicle,
2018
University of Alabama in Huntsville
Measurement Of Forces On A Flapping Wing Micro Aerial Vehicle, Darnisha Crane
Research Horizons Day Posters
No abstract provided.
Experimental Investigation Of A New Spiral Wingtip,
2018
International Islamic University - Malaysia
Experimental Investigation Of A New Spiral Wingtip, Naseeb Ahmed Siddiqui, Mohammed Aldheeb, Waqar Asrar, Erwin Sulaeman
International Journal of Aviation, Aeronautics, and Aerospace
Experiments on the relative merits and demerits of slotted wingtips mimicking a bird’s primary feathers have been performed. The real emargination length of feather tips, their flexibility and curved shapes during cruise are considered in the present study. The experiments were performed at a Reynolds number of 3.7 x 105 on a symmetric flat plate half wing of aspect ratio 3. Lift, drag and pitching moments were measured using a six component aerodynamic balance. Four different shapes inspired by bird primary feathers have been analysed. The rigid curved tip performed the best increasing the L/D ratio by 20%. This …
Wall-Modeled Large Eddy Simulation Of A Three-Dimensional Shock-Boundary Layer Interaction,
2018
Air Force Institute of Technology
Wall-Modeled Large Eddy Simulation Of A Three-Dimensional Shock-Boundary Layer Interaction, Nicholas J. Marco
Theses and Dissertations
The direct simulation of turbulent flows is prohibitive at high Reynolds numbers; thus, methods such as RANS and LES are used. However, these methods still require a large number of cells near a solid boundary. To circumvent this issue, a Wall-Modeled Large Eddy Simulation (WM-LES) can be used. Of interest is how these wall models perform in comparison to a Wall-Resolved Large Eddy Simulation (WR-LES) and experimental results of a shock turbulent boundary layer interactions (STBLI) and specifically, whether equilibrium wall models are sufficient to resolve the oscillatory and hence non-equilibrium nature of these flows or whether a non-equilibrium model …
An Efficient Euler Method To Predict Shock Migration On A Straked Delta Wing Design,
2018
Air Force Institute of Technology
An Efficient Euler Method To Predict Shock Migration On A Straked Delta Wing Design, Dylan N. Hope
Theses and Dissertations
In support of the Air Force Office of Scientific Research, this project sought to identify the significance of nonlinear aerodynamic phenomena in regards to LCO of a straked delta wing design. Previous works include unsteady Navier-Stokes aeroelastic analysis of various wing designs and flight test of F-16 transonic LCO with interest focused on oscillatory SITES behavior. The research presented within this investigation further expanded the understanding of unsteady aerodynamics by performing aeroelastic analysis of a wing oscillated in pitch with an Euler-based, boundary layer coupled numerical method (ZEUS). The wing was tested for a multitude of LCO parameters such as …
Nonlinear Control Of Underactuated And Constrained Systems,
2018
Embry-Riddle Aeronautical University
Nonlinear Control Of Underactuated And Constrained Systems, Derek Hoffman
Doctoral Dissertations and Master's Theses
It is the purpose of this document to elaborate on the control of systems that are underactuated or otherwise constrained. To do so, local- and global-coordinate formulations are implemented to generate well-defined system dynamics for a multitude of scenarios. These dynamics are shown to lie on manifolds defined by mathematical restrictions, allowing for singularity-free modeling for global considerations. Feed-back controllers by extension share these benefits, facilitating singularity-free control algorithms as a result. Further, unactuated degrees of freedom can be treated as additional constraints, resulting in an embedded manifold upon the original dynamics. A transformation between a provided set of dynamical …
Numerical Simulation Of Heat Transfer And Chemistry In The Wake Behind A Hypersonic Slender Body At Angle Of Attack,
2018
United States Air Force Academy
Numerical Simulation Of Heat Transfer And Chemistry In The Wake Behind A Hypersonic Slender Body At Angle Of Attack, Matthew J. Satchell, Jeffrey M. Layng, Robert B. Greendyke
Faculty Publications
The effect of thermal and chemical boundary conditions on the structure and chemical composition of the wake behind a 3D Mach 7 sphere-cone at an angle of attack of 5 degrees and an altitude of roughly 30,000 m is explored. A special emphasis is placed on determining the number density of chemical species which might lead to detection via the electromagnetic spectrum. The use of non-ablating cold-wall, adiabatic, and radiative equilibrium wall boundary conditions are used to simulate extremes in potential thermal protection system designs. Non-ablating, as well as an ablating boundary condition using the “steady-state ablation” assumption to compute …
2018 Oklahoma Research Day Guide Book,
2018
Southwestern Oklahoma State University
2018 Oklahoma Research Day Guide Book, Southwestern Oklahoma State University
Oklahoma Research Day Abstracts
This is the 2018 Oklahoma Research Day Guide Book. This book does not contain abstracts.
Aerodynamic Analysis Of Low Speed Wing Design Using Taguchi L9 Orthogonal Array,
2018
Embry-Riddle Aeronautical University
Aerodynamic Analysis Of Low Speed Wing Design Using Taguchi L9 Orthogonal Array, Kenneth Witcher, Ian Mcandrew, Elena Vishnevskaya
Publications
The study of aerodynamics has been preoccupied with understanding flight at increasing speeds and ultimately supersonic. Today, this pursuit has advanced the science for both Hypersonic and Transonic flight to near Mach 1 supporting economical commercial flight operations. This research presents the data from a Taguchi array on low speed with twin wing designs to establish the design parameters for their use in low speed and high altitude. Also presented is how aerodynamic advantages can be achieved through understanding the interactions of parameters and their use. This is compared to operational effectiveness when applied to remotely piloted aircraft that are …
Low Reynolds Number Numerical Simulation Of The Aerodynamic Coefficients Of A 3d Wing,
2018
International Islamic University - Malaysia
Low Reynolds Number Numerical Simulation Of The Aerodynamic Coefficients Of A 3d Wing, Khurshid Malik, Waqar Asrar, Erwin Sulaeman
International Journal of Aviation, Aeronautics, and Aerospace
A low Reynolds number, three-dimensional CFD analysis is carried out for a finite flat plate wing using the commercial CFD code STAR CCM+. The six-aerodynamic force and moment components CL, CD, CM, CN, Cl, CY and their derivatives are computed at a Reynolds numbers of 3x105 by varying the pitch, roll and yaw angles about the quarter chord point. The computed results have been validated with experimental aerodynamic balance data when possible. The results indicate that roll and yaw angle affect the aerodynamic coefficients of the flat plate …
Base Pressure Control Using Micro-Jets In Supersonic Flow Regimes,
2018
Monash University Malaysia
Base Pressure Control Using Micro-Jets In Supersonic Flow Regimes, Vigneshvaran Sethuraman, Sher Afghan Khan
International Journal of Aviation, Aeronautics, and Aerospace
Base pressure plays a vital role in aerospace-related applications and its control is essential in reduction of drag and improving fuel consumption. Low pressure at the base of Rockets, Missiles, bombs and shells are a very common problem happening at transonic and supersonic speeds. In most of the cases there is a significant dip in pressure at the base region which will have implications on the design of aerospace vehicles. This paper presents an experimental investigation carried out for flow control at supersonic regimes. Experiments were conducted to measure the base pressure in the base region and wall pressure distribution …
Mechanisms And Identification Of Unsteady Separation Development And Remediation,
2018
Portland State University
Mechanisms And Identification Of Unsteady Separation Development And Remediation, Matthew Scott Melius
Dissertations and Theses
Unsteady flow separation represents a highly complex and important area of study within fluid mechanics. The extent of separation and specific time scales over which it occurs are not fully understood and has significant consequences in numerous industrial applications such as helicopters, jet engines, hydroelectric turbines and wind turbines. A direct consequence of unsteady separation is the erratic movement of the separation point which causes highly dynamic and unpredictable loads on an airfoil. Current computational models underestimate the aerodynamic loads due to the inaccurate prediction of the emergence and severity of unsteady flow separation especially in response to a sudden …
Investigation Into Reynolds Number Effects On A Biomimetic Flapping Wing,
2018
Air Force Institute of Technology
Investigation Into Reynolds Number Effects On A Biomimetic Flapping Wing, Daniel K. Hope, Anthony M. Deluca, Ryan P. O'Hara
Faculty Publications
This research investigated the behavior of a Manduca sexta inspired biomimetic wing as a function of Reynolds number by measuring the aerodynamic forces produced by varying the characteristic wing length and testing at air densities from atmospheric to near vacuum. A six degree of freedom balance was used to measure forces and moments, while high speed cameras were used to measure wing stroke angle. An in-house created graphical user interface was used to vary the voltage of the drive signal sent to the piezoelectric actuator which determined the wing stroke angle. The Air Force Institute of Technology baseline 50 mm …
Structured Light-Field Focusing 3d Density Measurements Of A Supersonic Cone,
2018
University of Central Florida
Structured Light-Field Focusing 3d Density Measurements Of A Supersonic Cone, Ryonosuke Ozawa
Electronic Theses and Dissertations
This study describes three-dimensional (3D) quantitative visualization of density field in a supersonic flow around a cone spike. A measurement of the density gradient is conducted within a supersonic wind tunnel facility at the Propulsion and Energy Research Laboratory at the University of Central Florida utilizing Structured Light-Field Focusing Schlieren (SLLF). In conventional schlieren and Shadowgraph techniques, it is widely known that a complicated optical system is needed and yet visualizable area depends on an effective diameter of lenses and mirrors. Unlike these techniques, SLLF is yet one of the same family as schlieren photography, it is capable of non-intrusive …
Aerodynamic Design And Analysis Of A Large-Scale Stall-Regulated H-Type Vertical Axis Wind Turbine For An Offshire Floating Installation,
2018
Cork Institute of Technology
Aerodynamic Design And Analysis Of A Large-Scale Stall-Regulated H-Type Vertical Axis Wind Turbine For An Offshire Floating Installation, Brian Peter Hand
PhDs
Wind energy has witnessed a consistent expansion over the past decade, especially with the move to offshore installation. There is an increasing need to further exploit superior offshore wind resources, which is pushing multi-megawatt wind turbines into deeper water locations where the current popular horizontal axis wind turbine configuration is not entirely suitable. In particular, there has been a renewed interest in the vertical axis wind turbine (VAWT) configuration due to its inherent design attributes for an offshore floating application and also its potential to provide a significant reduction in the system cost of energy. However, challenges still remain as …
Flow Control Of Tandem Cylinders Using Plasma Actuators,
2018
University of Central Florida
Flow Control Of Tandem Cylinders Using Plasma Actuators, Jonah Larsen
Honors Undergraduate Theses
The flow over a set of tandem cylinders at a moderate Reynolds numbers (Re), and with different separation lengths has been studied. Two dimensional (2D) and three-dimensional (3D) plasma actuators were used to control the flow over the leading cylinder to change the vortex shedding, and subsequently the flow on the second cylinder. The 3D plasma actuator was segmented along the length of the cylinder with a spacing of λ = 4 while the 2D actuator simply ran straight down the span of the cylinder. Particle image velocimetry (PIV) measurements were used to investigate the flow along the central plane …
Specific Air Range (Sar) And How To Estimate It,
2018
Minnesota State University, Mankato
Specific Air Range (Sar) And How To Estimate It, Nihad E. Daidzic
Aviation Department Publications
No abstract provided.
Characterization Of Acoustic Modes In Aeroengines,
2018
University of Central Florida
Characterization Of Acoustic Modes In Aeroengines, Michelle Otero
Electronic Theses and Dissertations
Acoustic instabilities remain a key design concern faced in the development of liquid rocket engines. The interaction between the acoustic modes and the occurring combustion reactions can be detrimental to the engine. The fluctuating pressure waves resulting from the flame oscillations in the system can potentially lead to engine failure. For this reason, research in acoustic instabilities and methods to minimize the influences on the engine, has maintain interest in the aerospace community. The scope of this study was to design, optimize and characterize acoustic behaviors of a scaled rocket combustion chamber simulating acoustic pressure waves. Tangential and longitudinal acoustic …
