Shape Optimization Of Supersonic Bodies To Reduce Sonic Boom Signature, 2016 Washington University in St. Louis
Shape Optimization Of Supersonic Bodies To Reduce Sonic Boom Signature, Junhui Li
Engineering and Applied Science Theses & Dissertations
In recent years there has been resurgence of interest by aerospace industry and NASA in supersonic transport aircraft. In recent studies, the emphasis has been on shape optimization of supersonic plane to reduce the acoustic signature of sonic boom resulting from the supersonic aircraft at high altitude in cruise flight. Because of the limitations of in-flight testing and cost of laboratory scale testing, CFD technology provides an attractive alternative to aid in the design and optimization of supersonic vehicles. In last decade, the predictive capability of CFD technology has significantly improved because of substantial increase in computational power, which allows ...
Evaluation Of Various Turbulence Models For Shock-Wave Boundary Layer Interaction Flows, 2016 Washington University in St Louis
Evaluation Of Various Turbulence Models For Shock-Wave Boundary Layer Interaction Flows, Francis K. Acquaye
Engineering and Applied Science Theses & Dissertations
Despite the modeling capabilities of current computational fluid dynamics (CFD), there still exist problems and inconsistencies in simulating fluid flow in certain flow regimes. Most difficult are the high-speed transonic, supersonic and hypersonic wall-bounded turbulent flows with small or massive regions of separation. To address the problem of the lack of computational accuracy in turbulence modeling, NASA has established the Turbulence Modeling Resource (TMR) website and has issued the NASA 40% Challenge. The aim of this challenge is to identify and improve/develop turbulence and transition models as well as numerical techniques to achieve a 40% reduction in the predictive ...
Microscale Investigation Of Thermo-Fluid Transport In The Transition Fil, Region Of An Evaporating Capillary Meniscus Using A Microgravity Environment, 2016 University of Tennessee, Knoxville
Microscale Investigation Of Thermo-Fluid Transport In The Transition Fil, Region Of An Evaporating Capillary Meniscus Using A Microgravity Environment, Kenneth D. Kihm, Jeffrey S. Allen, Kevin P. Hallinan, David M. Pratt
In order to enhance the fundamental understanding of thin film evaporation and thereby improve the critical design concept for two-phase heat transfer devices, microscale heat and mass transport is to be investigated for the transition film region using state-of-the-art optical diagnostic techniques. By utilizing a microgravity environment, the length scales of the transition film region can be extended sufficiently, from submicron to micron, to probe and measure the microscale transport fields which are affected by intermolecular forces. Extension of the thin film dimensions under microgravity will be achieved by using a conical evaporator made of a thin silicon substrate under ...
Nanocharacterization Of Bio-Silica Using Atomic Force And Ultrasonic Force Microscopy, 2016 Brown University
Nanocharacterization Of Bio-Silica Using Atomic Force And Ultrasonic Force Microscopy, Vinaypreet S. Gill, Kevin P. Hallinan, N. S. Brar
Nanotechnology has become central to our research efforts to fabricate relatively smaller size devices, which are more versatile than their older and larger predecessors. Silica is a very important material in this regard. Recently, a new biomimetically inspired path to silica production has been demonstrated. This processing technique was inspired from biological organisms, such as marine diatoms, which produce silica at ambient conditions and almost neutral ph with beautiful control over location and structure. Recently, several researchers have demonstrated that positional control of silica formed could be achieved by application of an electric field to locate charged enzymes responsible for ...
Leveraging Students’ Passion And Creativity: Ethos At The University Of Dayton, 2016 University of Dayton
Leveraging Students’ Passion And Creativity: Ethos At The University Of Dayton, Margaret Pinnell, Malcolm Daniels, Kevin P. Hallinan, Gretchen Berkemeier
The Engineers in Technical Humanitarian Opportunities of Service-learning (ETHOS) program was developed in the spring of 2001 by an interdisciplinary group (electrical, chemical, civil and mechanical) of undergraduate engineering students at the University of Dayton (UD). ETHOS was founded on the belief that engineers are more apt and capable to appropriately serve our world if they have an understanding of technology’s global linkage with values, culture, society, politics, and the economy. Since 2001, the ETHOS program at UD has grown and changed.
From conceptualization, to implementation, to maturation and national recognition, the program has addressed challenges of academic acceptance ...
Industrial Solid-State Energy Harvesting: Mechanisms And Examples, 2016 Carnegie Mellon University
Industrial Solid-State Energy Harvesting: Mechanisms And Examples, Matthew Kocoloski, Carl Eger, Robin Mccarty, Kevin P. Hallinan, J. Kelly Kissock
This paper explores the potential for solid-state energy harvesting in industrial applications. In contrast to traditional heat recovery, the output of solid-state devices is electricity, which can be readily used in virtually any plant. The progress in harvesting waste heat via thermoelectric and thermionic generators is described. With second law efficiencies now approaching 50% and 80% respectively, we show that these technologies are on the cusp of practical use. Finally, we present an example of energy harvesting using thermionic devices in an industrial application. The example considers energy harvesting from a furnace at a glass manufacturing facility where exhaust gases ...
Energy Information Augmented Community-Based Energy Reduction, 2016 University of Dayton
Energy Information Augmented Community-Based Energy Reduction, Kevin P. Hallinan, Harvey Enns, Stephenie Ritchey, Phil Brodrick, Nathan Lammers, Nichole Hanus, Mark Rembert, Tony Rainsberger
More than one-half of all U.S. states have instituted energy efficiency mandates requiring utilities to reduce energy use. To achieve these goals, utilities have been permitted rate structures to help them incentivize energy reduction projects. This strategy is proving to be only modestly successful in stemming energy consumption growth. By the same token, community energy reduction programs have achieved moderate to very significant energy reduction. The research described here offers an important tool to strengthen the community energy reduction efforts—by providing such efforts energy information tailored to the energy use patterns of each building occupant. The information provided ...
Clean Energy Infrastructure Educational Initiative, 2016 University of Dayton
Clean Energy Infrastructure Educational Initiative, Kevin P. Hallinan, James A. Menart, Robert Gilbert
The Clean Energy Infrastructure Educational Initiative represents a collaborative effort by the University of Dayton, Wright State University and Sinclair Community College. This effort above all aimed to establish energy related programs at each of the universities while also providing outreach to the local, state-wide, and national communities. At the University of Dayton, the grant has aimed at: solidfying a newly created Master's program in Renewable and Clean Energy; helping to establish and staff a regional sustainability organization for SW Ohio. As well, as the prime grantee, the University of Dayton was responsible for ensuring curricular sharing between WSU ...
A Study Of The Fundamental Operations Of A Capillary Driven Heat Transfer Device In Both Normal And Low Gravity Part 1-Liquid Slug Formation In Low Gravity, Jeffrey S. Allen, Kevin P. Hallinan, Jack Lekan
Research has been conducted to observe the operation of a capillary pumped loop (CPL) in both normal and low gravity environments in order to ascertain the causes of device failure. The failures of capillary pumped heat transport devices in low gravity; specifically; evaporator dryout, are not understood and the available data for analyzing the failures is incomplete.
To observe failure in these devices an idealized experimental CPL was configured for testing in both a normal-gravity and a low-gravity environment. The experimental test loop was constructed completely of Pyrex tubing to allow for visualization of system operations. Heat was added to ...
Applying Newton’S Law Of Cooling When The Target Keeps Changing Temperature, Such As In Stratospheric Ballooning Missions, 2016 University of Minnesota - Twin Cities / MN Space Grant
Applying Newton’S Law Of Cooling When The Target Keeps Changing Temperature, Such As In Stratospheric Ballooning Missions, James Flaten, Kaye Smith, Erick Agrimson
2016 Academic High Altitude Conference
Newton’s Law of Cooling describes how a “small” system, such as a thermometer, comes to thermal equilibrium with a “large” system, such as its environment, as a function of time. It is typically applied when the environment is in thermal equilibrium and the conditions are such that the thermal decay time for the thermometer is a constant. Neither of these conditions are met when measuring environmental (i.e. atmospheric) temperature using a thermometer mounted in a payload lofted into the stratosphere under weather balloons. In this situation the thermometer is in motion so it encounters layer after layer of ...
Estimation Of Performance Airspeeds For High-Bypass Turbofans Equipped Transport-Category Airplanes, 2016 AAR Aerospace Consulting, LLC
Estimation Of Performance Airspeeds For High-Bypass Turbofans Equipped Transport-Category Airplanes, Nihad E. Daidzic
Journal of Aviation Technology and Engineering
Conventional Mach-independent subsonic drag polar does not replicate the real airplane drag characteristics exactly and especially not in the drag-divergence region due to shock-induced transonic wave drag. High-bypass turbofan thrust is a complicated function of many parameters that eludes accurate predictions for the entire operating envelope and must be experimentally verified. Fuel laws are also complicated functions of many parameters which make optimization and economic analysis difficult and uncertain in the conceptual design phase. Nevertheless, mathematical models and predictions have its important place in aircraft development, design, and optimization. In this work, airspeed-dependent turbofan thrust and the new fuel-law model ...
Flow Meter Test Rig, 2016 California Polytechnic State University, San Luis Obispo
Flow Meter Test Rig, Cory Davis, Emily Guss, Michael Swartz
As part of a fluid mechanics laboratory, there should be an experiment that demonstrates the proper use of flow meters, devices that are necessary and relevant in many fluids-related industries. In order to provide students with exposure to these types of devices and how they work, a test rig was developed with the ability to interchange a variety of flow meters in order to broaden the students’ knowledge of the different types of measuring devices. This report was also written to outline the steps taken to ensure the test rig would match a laboratory and industry setting. Additionally, it was ...
Three-Dimensional Simulation For Fast Forward Flight Of A Calliope Hummingbird, 2016 Vanderbilt University
Three-Dimensional Simulation For Fast Forward Flight Of A Calliope Hummingbird, Jialei Song, Bret W. Tobalske, Don Powers, Tyson Hedrick, Haoxiang Luo
Faculty Publications - Department of Biology and Chemistry
We present a computational study of flapping-wing aerodynamics of a calliope hummingbird (Selasphorus calliope) during fast forward flight. Three-dimensional wing kinematics were incorporated into the model by extracting time-dependent wing position from high-speed videos of the bird flying in a wind tunnel at 8.3 m s−1. The advance ratio, i.e. the ratio between flight speed and average wingtip speed, is around one. An immersed-boundary method was used to simulate flow around the wings and bird body. The result shows that both downstroke and upstroke in a wingbeat cycle produce significant thrust for the bird to overcome drag ...
Time-Of-Flight Based Sonic Speed Measurements For Cold Gas Thruster Development, 2016 University of Arkansas, Fayetteville
Time-Of-Flight Based Sonic Speed Measurements For Cold Gas Thruster Development, Brandon W. Kempf
Mechanical Engineering Undergraduate Honors Theses
The purpose of this thesis is to explore an experiment developed for validating the usage of a gaseous solution of water and propylene glycol for cold gas propulsion. The experiment involves a “Time of Flight” method of calculating the speed of sound in the gas and the corresponding specific heat ratio using a copper tube, two MEMS microphones, a piezoelectric speaker, and data-acquisition hardware. The experiment was calibrated using the known thermodynamic properties of air. The accuracy of the experiment was found to be within 0.6% for calculations of the speed of sound in air and within 1.0 ...
A Computational Evaluation Of Transonic Wind Tunnel Wall Interference On High Aspect Ratio Models In The Arnold Engineering Development Complex 16 Foot Transonic Tunnel, 2016 University of Tennessee - Knoxville
A Computational Evaluation Of Transonic Wind Tunnel Wall Interference On High Aspect Ratio Models In The Arnold Engineering Development Complex 16 Foot Transonic Tunnel, William Calain Schuman
One of the inherent difficulties in utilizing a ventilated test section wind tunnel is the interaction of the model flow field and the test section walls. If high quality aerodynamic data is required for the system under test it is necessary to determine the impact of the test section walls on the flow field around the model. A parametric study was undertaken using the CFD code USM3Dns to determine the impact of model size and wingspan on observed transonic wind tunnel wall interference. The study used a simplified model of the Propulsion Wind Tunnel 16T test section as the test ...
Improved Modeling Of Atmospheric Entry For Meteors With Nose Radii Between 5cm And 10m, 2016 University of Tennessee - Knoxville
Improved Modeling Of Atmospheric Entry For Meteors With Nose Radii Between 5cm And 10m, Jakob Dale Brisby
Atmospheric entry studies typically look closely at the peak heating rate that a body encounters during its trajectory. This is an extremely important phenomenon to study because it allows engineers to determine if a trajectory is possible with given materials and craft design specifications. It also allows designers to choose what type of method will be used for mitigating the enormous heat fluxes during entry. In general, it is accepted that during the super-sonic flight regime the body will continue to be heated and an ablative heat shield often is used to deal with these heating processes. The theory outlined ...
Numerical Investigation Of Full Scale Thunderstorm Downbursts: A Parametric Study And Comparison To Meteorological Model, 2016 The University of Western Ontario
Numerical Investigation Of Full Scale Thunderstorm Downbursts: A Parametric Study And Comparison To Meteorological Model, Christopher Oreskovic
Electronic Thesis and Dissertation Repository
A series of Large Eddy Simulations using an atmospheric meteorological cloud model have been used to investigate the important geometric and thermal parameters that influence a thunderstorm downburst outflow, as it pertains specifically to the idealized cooling source model. A separate set of Large Eddy Simulations make use of the same idealized cooling source model, in a realistic atmospheric base state using real field sounding data, in an attempt to make a quantifiable comparison to a downburst from a full cloud simulation. Randomness has been added to the cooling source forcing function to mimic the thermal variation in a real ...
Effects Of Body Weight Modification On Internal Knee Contact Forces During Gait, 2015 University of Dayton
Effects Of Body Weight Modification On Internal Knee Contact Forces During Gait, Allison Kinney, Heather Vincent, Melinda Harman, James Coburn, Darryl D'Lima, Benjamin Fregly
Obesity is commonly considered a risk factor for the development of knee osteoarthritis. Previous studies have shown that reductions in body weight correspond to reductions in total knee joint compressive forces (as calculated by inverse dynamics). A recent study showed that external knee load measurements are not strong predictors of internal knee contact forces. Therefore, direct measurement of knee contact force is important for understanding how body weight changes impact knee joint loading. Force-measuring knee implants can directly measure internal knee contact forces.
Muscle Synergies Improve Estimation Of Knee Contact Forces During Walking, 2015 University of Florida
Muscle Synergies Improve Estimation Of Knee Contact Forces During Walking, Benjamin Fregly, Jonathan Walter, Allison Kinney, Scott Banks, Darryl D'Lima, Thor Besier, David Lloyd
This study investigates whether use of subject-specific muscle synergies can improve optimization predictions of muscle excitation patterns and knee contact forces during walking. Muscle synergies describe how a small number of neural commands generated by the nervous system can be linearly combined to produce the broad range of muscle electromyographic (EMG) signals measured experimentally. By quantifying the interdependence of individual EMG signals, muscle synergies provide dimensionality reduction for the neural control redundancy problem. Our hypothesis was that use of subjectspecific muscle synergies to limit muscle excitation patterns would improve prediction of muscle EMG patterns at the hip, knee, and ankle ...
Muscle Contributions To Frontal And Transverse Plane Whole-Body Angular Momentum, 2015 University of Texas at Austin
Muscle Contributions To Frontal And Transverse Plane Whole-Body Angular Momentum, Richard Neptune, Craig Mcgowan, Allison Kinney
The purpose of this study was to build upon previous work by analyzing how gravity and individual muscles contribute to frontal and traverse plane whole-body angular momentum. Identifying which muscles are responsible for generating angular momentum has important implications for the diagnosis and treatment of movement disorders.