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Investigation Of The Under-Body Flow Field Of A Prototype Long-Range Electric Vehicle, Matthew P. Nguyen 2019 California Polytechnic State University, San Luis Obispo

Investigation Of The Under-Body Flow Field Of A Prototype Long-Range Electric Vehicle, Matthew P. Nguyen

Master's Theses and Project Reports

This thesis presents changes to the design of the Prototype Vehicles Laboratory (PROVE Lab) Endurance Car, an electric car intended to break the Guinness World Record for the single-charge range of an electric vehicle. The design range is 1609.34 km, however at the design velocity of 104.6 kph, the drag is 196 N; which requires more battery capacity than the 100 kWh maximum of the baseline model. With a fixed frontal area, drag reduction can come from lowered velocity or reduced CD. CD reduction is attempted in four ways: side skirts between the fenders, a raised ride height ...


Development Of A Tailored Flight Test Approach For Small Unmanned Aircraft Systems, Neil A. Wolfe, Neil A. Wolfe 2019 California Polytechnic State University, San Luis Obispo

Development Of A Tailored Flight Test Approach For Small Unmanned Aircraft Systems, Neil A. Wolfe, Neil A. Wolfe

Master's Theses and Project Reports

This document contains the details of a study conducted to determine an effective performance flight test approach specifically for small Unmanned Aircraft Systems (sUAS). This was done by taking proven procedures and documentation from the FAA and the Air Force for manned aircraft and tailoring them specifically for use with sUAS flight test programs. A ‘sUAS Flight Testing Handbook’ was created from the proceedings to aid commercial organizations and recreational developers conducting sUAS research without access to flight test experience. A performance flight test program was conducted with the AeroVironment RQ-20 Puma sUAS using the developed approach to verify that ...


Improving Boron For Combustion Applications, Kerri-lee Annique Chintersingh 2019 New Jersey Institute of Technology

Improving Boron For Combustion Applications, Kerri-Lee Annique Chintersingh

Dissertations

Boron has received much attention as a potential additive to explosives and propellants due to its high theoretical gravimetric and volumetric heating values. The challenge, however, is that boron particles tend to agglomerate, have lengthy ignition delays and very low combustion rates. Prior research indicates that boron’s long ignition delays are due to its inhibiting naturally occurring oxide layer, impeding the diffusion of reactants for oxidation. For combustion, current studies report that boron particles have two consecutive stages, but the actual reaction mechanism is poorly understood. Despite many years of relevant research, quantitative combustion data on micron-sized boron particles ...


Cislunar Trajectory Generation With Sun-Exclusion Zone Constraints Using A Genetic Algorithm And Direct Method Hybridization, Joshua A. Ostman 2019 Air Force Institute of Technology

Cislunar Trajectory Generation With Sun-Exclusion Zone Constraints Using A Genetic Algorithm And Direct Method Hybridization, Joshua A. Ostman

Theses and Dissertations

Space missions to the Moon have received renewed interest in recent decades. Science missions continue to be sent to the Moon, and several space agencies have aspirations of establishing a human presence on the Moon. With the increased number of artificial objects in cislunar space, the problem of tracking these objects arises. Optical sensors are able to track these objects in deep space. However, optical sensors cannot track objects that are close to the Sun as viewed from the observer. This unobservable region is the Sun-exclusion zone (SEZ). This research attempts to create optimal Moon-Earth transfers which are completely in ...


Computational Finite Element Analysis Of Adaptive Gas Turbine Stator-Rotor Flow Interactions For Future Vertical Lift Propulsion, Nikita Kozak, Luis Bravo, Muthuvel Murugan, Anindya Ghoshal, Yu Yu Khine, Yuri Bazilevs, Ming-Chen Hsu 2019 Iowa State University

Computational Finite Element Analysis Of Adaptive Gas Turbine Stator-Rotor Flow Interactions For Future Vertical Lift Propulsion, Nikita Kozak, Luis Bravo, Muthuvel Murugan, Anindya Ghoshal, Yu Yu Khine, Yuri Bazilevs, Ming-Chen Hsu

Ming-Chen Hsu

The objective of this work is to computationally investigate the impact of an incident-tolerant rotor blade concept on gas-turbine engine performance under off-design conditions. Currently, gas-turbine engines are designed to operate at a single condition with nearly fixed rotor speeds. Operation at off-design conditions, such as during hover flight or during takeoff, causes the turbine blade flow to excessively separate introducing performance degradations, excessive noise, and critical loss of operability. To address these issues, the benefits of using an incidence-tolerant rotor blade concept is explored based on a novel concept that articulates the rotating turbine blade synchronously with the stator ...


Computational Finite Element Analysis Of Adaptive Gas Turbine Stator-Rotor Flow Interactions For Future Vertical Lift Propulsion, Nikita Kozak, Luis Bravo, Muthuvel Murugan, Anindya Ghoshal, Yu Yu Khine, Yuri Bazilevs, Ming-Chen Hsu 2019 Iowa State University

Computational Finite Element Analysis Of Adaptive Gas Turbine Stator-Rotor Flow Interactions For Future Vertical Lift Propulsion, Nikita Kozak, Luis Bravo, Muthuvel Murugan, Anindya Ghoshal, Yu Yu Khine, Yuri Bazilevs, Ming-Chen Hsu

Mechanical Engineering Conference Presentations, Papers, and Proceedings

The objective of this work is to computationally investigate the impact of an incident-tolerant rotor blade concept on gas-turbine engine performance under off-design conditions. Currently, gas-turbine engines are designed to operate at a single condition with nearly fixed rotor speeds. Operation at off-design conditions, such as during hover flight or during takeoff, causes the turbine blade flow to excessively separate introducing performance degradations, excessive noise, and critical loss of operability. To address these issues, the benefits of using an incidence-tolerant rotor blade concept is explored based on a novel concept that articulates the rotating turbine blade synchronously with the stator ...


Lifestyle And Solutions: An Investigation Of Fatigue In Collegiate Aviation, Aaron Teo, Erik Levin 2019 Purdue University

Lifestyle And Solutions: An Investigation Of Fatigue In Collegiate Aviation, Aaron Teo, Erik Levin

The Journal of Purdue Undergraduate Research

No abstract provided.


Micrometeoroid Impacts On Periodic Spacecraft Structures, Victoria West, Luis Buades, Hanson-Lee Harjono 2019 Purdue University

Micrometeoroid Impacts On Periodic Spacecraft Structures, Victoria West, Luis Buades, Hanson-Lee Harjono

The Journal of Purdue Undergraduate Research

No abstract provided.


Origins Of Space Food From Mercury To Apollo, Celine Chang 2019 Purdue University

Origins Of Space Food From Mercury To Apollo, Celine Chang

The Journal of Purdue Undergraduate Research

No abstract provided.


Twinning-Induced Pseudoelastic Behavior In (Mow)85(Tati)7.5zr7.5, Aayush Sharma, Valery I. Levitas, Prashant Signh, Anup Basak, Ganesh Balasubramanian, Duane D. Johnson 2019 Iowa State University

Twinning-Induced Pseudoelastic Behavior In (Mow)85(Tati)7.5zr7.5, Aayush Sharma, Valery I. Levitas, Prashant Signh, Anup Basak, Ganesh Balasubramanian, Duane D. Johnson

Ganesh Balasubramanian

We provide a critical atomistic evidence of pseudoelastic behavior in complex solid-solution BCC Mo-W-Ta-Ti-Zr alloy. Prior to this work, only limited single-crystal BCC solids of pure metals and quaternary alloys have shown pseudoelastic behavior at low temperatures and high strain rates. The deformation mechanisms investigated using classical molecular simulations under tensile-compressive loading reveal temperature-dependent pseudoelastic behavior aided by twinning during the loading-unloading cycle. The pseudoelasticity is found to be independent of loading directions with identical cyclic deformation characteristics during uniaxial loading. Additionally, temperature variation from 77 to 1500 K enhances the elastic strain recovery in the alloy.


License To Launch: The Regulatory Future Of Commercial Ballistic Travel, Jacob Weindling 2019 University of Minnesota Law School

License To Launch: The Regulatory Future Of Commercial Ballistic Travel, Jacob Weindling

Minnesota Journal of Law, Science & Technology

No abstract provided.


Gaussian Conditionally Markov Sequences: Theory With Application, Reza Rezaie 2019 University of New Orleans

Gaussian Conditionally Markov Sequences: Theory With Application, Reza Rezaie

University of New Orleans Theses and Dissertations

Markov processes have been widely studied and used for modeling problems. A Markov process has two main components (i.e., an evolution law and an initial distribution). Markov processes are not suitable for modeling some problems, for example, the problem of predicting a trajectory with a known destination. Such a problem has three main components: an origin, an evolution law, and a destination. The conditionally Markov (CM) process is a powerful mathematical tool for generalizing the Markov process. One class of CM processes, called $CM_L$, fits the above components of trajectories with a destination. The CM process combines the Markov ...


Ultra-Broadband Infrared Absorption By Tapered Hyperbolic Multilayer Waveguides, Huixu Deng, Cherian J. Mathai, Shubhra Gangopadhyay, Jie Gao, Xiaodong Yang 2019 Missouri University of Science and Technology

Ultra-Broadband Infrared Absorption By Tapered Hyperbolic Multilayer Waveguides, Huixu Deng, Cherian J. Mathai, Shubhra Gangopadhyay, Jie Gao, Xiaodong Yang

Jie Gao

Ultra-broadband strong absorption over 92% covering the infrared wavelength range of 1 ~ 6μm is demonstrated by using the tapered hyperbolic Au-SiO2 multilayer waveguides on glass substrates. Such broadband absorption is formed by the stop-light modes at various wavelengths located at different waveguide widths. A planar hyperbolic waveguide model is built to determine the stop-light modes by considering both forward and backward guided modes. The stop-light modes located inside the Au-SiO2 multilayer waveguide are simulated at the absorption peaks by reducing the Au loss. Tapered multilayer waveguides with varying top widths are further simulated, fabricated and measured, indicating the ...


Wavelength-Selective Mid-Infrared Metamaterial Absorbers With Multiple Tungsten Cross Resonators, Zhigang Li, Liliana Stan, David A. Czaplewski, Xiaodong Yang, Jie Gao 2019 Missouri University of Science and Technology

Wavelength-Selective Mid-Infrared Metamaterial Absorbers With Multiple Tungsten Cross Resonators, Zhigang Li, Liliana Stan, David A. Czaplewski, Xiaodong Yang, Jie Gao

Jie Gao

Wavelength-selective metamaterial absorbers in the mid-infrared range are demonstrated by using multiple tungsten cross resonators. By adjusting the geometrical parameters of cross resonators in single-sized unit cells, near-perfect absorption with single absorption peak tunable from 3.5 µm to 5.5 µm is realized. The combination of two, three, or four cross resonators of different sizes in one unit cell enables broadband near-perfect absorption at mid-infrared range. The obtained absorption spectra exhibit omnidirectionality and weak dependence on incident polarization. The underlying mechanism of near-perfect absorption with cross resonators is further explained by the optical mode analysis, dispersion relation and equivalent ...


Assessment Of Turbulence Models In A Hypersonic Cold-Wall Turbulent Boundary Layer, Junji Huang, Jorge-Valentino Bretzke, Lian Duan 2019 Missouri University of Science and Technology

Assessment Of Turbulence Models In A Hypersonic Cold-Wall Turbulent Boundary Layer, Junji Huang, Jorge-Valentino Bretzke, Lian Duan

Lian Duan

In this study, the ability of standard one- or two-equation turbulence models to predict mean and turbulence profiles, the Reynolds stress, and the turbulent heat flux in hypersonic cold-wall boundary-layer applications is investigated. The turbulence models under investigation include the one-equation model of Spalart-Allmaras, the baseline k-ω model by Menter, as well as the shear-stress transport k-ω model by Menter. Reynolds-Averaged Navier-Stokes (RANS) simulations with the different turbulence models are conducted for a flat-plate, zero-pressure-gradient turbulent boundary layer with a nominal free-stream Mach number of 8 and wall-to-recovery temperature ratio of 0.48, and the RANS results are compared with ...


Spatially Continuous Strain Monitoring Using Distributed Fiber Optic Sensors Embedded In Carbon Fiber Composites, Sasi Jothibasu, Yang Du, Sudharshan Anandan, Gurjot S. Dhaliwal, Rex E. Gerald II, Steve Eugene Watkins, K. Chandrashekhara, Jie Huang 2019 Missouri University of Science and Technology

Spatially Continuous Strain Monitoring Using Distributed Fiber Optic Sensors Embedded In Carbon Fiber Composites, Sasi Jothibasu, Yang Du, Sudharshan Anandan, Gurjot S. Dhaliwal, Rex E. Gerald Ii, Steve Eugene Watkins, K. Chandrashekhara, Jie Huang

K. Chandrashekhara

A distributed fiber optic strain sensor based on Rayleigh backscattering, embedded in a fiber-reinforced polymer composite, has been demonstrated. The optical frequency domain reflectometry technique is used to analyze the backscattered signal. The shift in the Rayleigh backscattered spectrum is observed to be linearly related to the change in strain of the composite material. The sensor (standard single-mode fiber) is embedded between the layers of the composite laminate. A series of tensile loads is applied to the laminate using an Instron testing machine, and the corresponding strain distribution of the laminate is measured. The results show a linear response indicating ...


Spatially Continuous Strain Monitoring Using Distributed Fiber Optic Sensors Embedded In Carbon Fiber Composites, Sasi Jothibasu, Yang Du, Sudharshan Anandan, Gurjot S. Dhaliwal, Rex E. Gerald II, Steve Eugene Watkins, K. Chandrashekhara, Jie Huang 2019 Missouri University of Science and Technology

Spatially Continuous Strain Monitoring Using Distributed Fiber Optic Sensors Embedded In Carbon Fiber Composites, Sasi Jothibasu, Yang Du, Sudharshan Anandan, Gurjot S. Dhaliwal, Rex E. Gerald Ii, Steve Eugene Watkins, K. Chandrashekhara, Jie Huang

Steve Eugene Watkins

A distributed fiber optic strain sensor based on Rayleigh backscattering, embedded in a fiber-reinforced polymer composite, has been demonstrated. The optical frequency domain reflectometry technique is used to analyze the backscattered signal. The shift in the Rayleigh backscattered spectrum is observed to be linearly related to the change in strain of the composite material. The sensor (standard single-mode fiber) is embedded between the layers of the composite laminate. A series of tensile loads is applied to the laminate using an Instron testing machine, and the corresponding strain distribution of the laminate is measured. The results show a linear response indicating ...


Spatially Continuous Strain Monitoring Using Distributed Fiber Optic Sensors Embedded In Carbon Fiber Composites, Sasi Jothibasu, Yang Du, Sudharshan Anandan, Gurjot S. Dhaliwal, Rex E. Gerald II, Steve Eugene Watkins, K. Chandrashekhara, Jie Huang 2019 Missouri University of Science and Technology

Spatially Continuous Strain Monitoring Using Distributed Fiber Optic Sensors Embedded In Carbon Fiber Composites, Sasi Jothibasu, Yang Du, Sudharshan Anandan, Gurjot S. Dhaliwal, Rex E. Gerald Ii, Steve Eugene Watkins, K. Chandrashekhara, Jie Huang

Jie Huang

A distributed fiber optic strain sensor based on Rayleigh backscattering, embedded in a fiber-reinforced polymer composite, has been demonstrated. The optical frequency domain reflectometry technique is used to analyze the backscattered signal. The shift in the Rayleigh backscattered spectrum is observed to be linearly related to the change in strain of the composite material. The sensor (standard single-mode fiber) is embedded between the layers of the composite laminate. A series of tensile loads is applied to the laminate using an Instron testing machine, and the corresponding strain distribution of the laminate is measured. The results show a linear response indicating ...


Feasibility Of Circular Orbits For Proximity Operations In Strongly Perturbed Environments Around Uniformly Rotating Asteroids, Nicholas Peter Liapis 2019 Embry-Riddle Aeronautical University

Feasibility Of Circular Orbits For Proximity Operations In Strongly Perturbed Environments Around Uniformly Rotating Asteroids, Nicholas Peter Liapis

Dissertations and Theses

Asteroids have been mapped and observed since 1801 when an Italian astronomer Guiseppe Piazzi discovered Ceres (Serio, Manara, & Sicoli, 2002). Since then, asteroids have been growing in popularity throughout the scientific community because they are thought to hold the information we need to understand how the solar system developed and why life exists on earth, as well as potential precious resources. This research studies different types of orbits that have been performed to date around asteroids and how they can be reworked to require less control effort. Different types of missions that have been sent to asteroids are discussed, as ...


Nonlinear Estimation And Control Methods For Mechanical And Aerospace Systems Under Actuator Uncertainty, Krishna Bhavithavya Kidambi 2019 Embry-Riddle Aeronautical University

Nonlinear Estimation And Control Methods For Mechanical And Aerospace Systems Under Actuator Uncertainty, Krishna Bhavithavya Kidambi

Dissertations and Theses

Air flow velocity field control is of crucial importance in aerospace applications to prevent the potentially destabilizing effects of phenomena such as cavity ow oscillations, flow separation, flow-induced limit cycle oscillations (LCO) (flutter), vorticity, and acoustic instabilities. Flow control is also important in aircraft applications to reduce drag in aircraft wings for improved flight performance. Although passive flow control approaches are often utilized due to their simplicity, active flow control (AFC) methods can achieve improved flight performance over a wider range of time-varying operating conditions by automatically adjusting their level of control actuation in response to real-time sensor measurements. Although ...


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