Mechanical Engineering Commons^™

Computational Study On Suppression Of Airfoil Flow Separation Using High-Frequency Translational Surface Actuation, Bibek Gupta

Honors Theses

Flow separation is a phenomenon that occurs when pressure increases in the streamwise direction of a flow, making a distinctive boundary layer or separation bubble. It causes aircraft to experience an increase in drag and noise and a decrease in a lift, hence degrading their aviation performance. This study uses numerical simulations to understand better the effects of high-frequency translational surface actuation (HFTSA) on flow separation control. The numerical simulations mimic the experimental parameters of an experiment performed by Okoye et al. on using the HFTSA system to control flow separation. A symmetrical airfoil structure of chord length of 0.3 …

Automated Scenario Generation Using Halton Sequences For The Verification Of Autonomous Vehicle Behavior In Simulation, Andrew Ferree

Doctoral Dissertations and Master's Theses

As autonomous vehicles continue to develop, verifying their safety remains a large hurdle to mass adoption. One component of this is testing, however it has been shown that it is impractical to statistically prove an autonomous vehicle’s safety using real-world testing alone. Therefore, simulation tools and other virtual testing methods are being employed to assist with the verification process. Testing in simulation still faces some of the challenges of the real world, such as the difficulty in exhaustively testing the system in all scenarios it will encounter. Manual scenario creation is time consuming and does not guarantee scenario coverage. Pseudo-random …

Application Of Physically Based Semi-Distributed Hec-Hms Model For Flow Simulation In Tributary Catchments Of Kaohsiung Area Taiwan, Fiaz Hussain, Ray-Shyan Wu, Kai-Chun Yu

Journal of Marine Science and Technology–Taiwan

Hydrologic modeling is a commonly used tool to understand the rainfallerunoff processes of gauged and ungauged catchments for proper quantitative estimation of water resources availability. In the present study, an attempt is made to simulate surface runoff using a physically based semi-distributed hydrological (HEC-HMS) model for four local-scale tributary catchments of Kaohsiung area Taiwan. The input physical parameters of the model were calculated and preprocessed in HEC-GeoHMS based on digital elevation model (DEM), land use, soil and hydro-meteorological data. The model performance was satisfactory with Nash Sutcliffe Efficiency (NSE) ¼ 0.51 to 0.86 and the coefficient of determination (R2) ¼ …

Fluid-Structure Interaction For A Deformable Anisotropic Cylinder: A Case Study, Jared T. Decker

Honors Undergraduate Theses

For a structure designed to interact with the surrounding fluid, structural deformation under loads induced by fluid flows is an important factor to consider, and one which is traditionally difficult to account for analytically. Coupling the finite element method for structural analysis with the finite volume method for the determination of fluid response allows for accurate simulation of the pressure and shearing loads applied by the fluid onto the fluid-structure interface, while also determining localized structural displacements that would cause changes to the geometry of the interface. This work seeks to simulate the behavior of cylinders with varying heights and …

Pore Microstructure Impacts On Lithium Ion Transport And Rate Capability Of Thick Sintered Electrodes, Ziyang Nie, Rohan Parai, Chen Cai, Charles Michaelis, Jacob M. Lamanna, Daniel S. Hussey, David L. Jacobson, Dipankar Ghosh, Gary M. Koenig Jr.

Mechanical & Aerospace Engineering Faculty Publications

Increasing electrode thickness is one route to improve the energy density of lithium-ion battery cells. However, restricted Li⁺ transport in the electrolyte phase through the porous microstructure of thick electrodes limits the ability to achieve high current densities and rates of charge/discharge with these high energy cells. In this work, processing routes to mitigate transport restrictions were pursued. The electrodes used were comprised of only active material sintered together into a porous pellet. For one of the electrodes, comparisons were done between using ice-templating to provide directional porosity and using sacrificial particles during processing to match the geometric density …

Development Of A Method To Model An Enclosed, Coaxial Carbon Nanotube Speaker With Experimental Validation, Suraj Prabhu

Dissertations, Master's Theses and Master's Reports

Carbon nanotube (CNT) speakers operate on heat as compared to conventional loudspeakers that operate on vibration. CNT speakers are extremely lightweight, stretchable, flexible, and have high operating temperatures. Due to these advantages, CNT speakers are being considered as a viable replacement option for conventional loudspeakers. One such application is automotive exhaust noise control. The goal of this research is to design an enclosed, coaxial CNT speaker and to develop a modeling method to model this speaker using COMSOL Multiphysics.

As part of this research, an enclosed, coaxial CNT speaker was designed and manufactured for automotive exhaust noise control. The first …

Formula Sae Design Validation Through Lap Time Simulation, Noah Gresser, Akos Jasper, Michael Metropoulos, Paul Buczynski, James Volcansek

Williams Honors College, Honors Research Projects

Lap time simulation is capable of advancing Zips Racing into a new, modern era for future vehicle designs. Through the use of VI-grade simulation software, Zips Racing was able to validate its current combustion and electric vehicle designs in spite of the challenges brought on to the team as a result of the COVID-19 pandemic. Throughout this project, the design team gained an enhanced understanding of suspension designs and optimizations through the usage of computer simulations. As a result, the teams have a better understanding of the fundamental changes that need to occur to enhance the race team’s final race …

Equations Of State For Warm Dense Carbon From Quantum Espresso, Derek J. Schauss

Theses and Dissertations

Warm dense plasma is the matter that exists, roughly, in the range of 10,000 to 10,000,000 Kelvin and has solid-like densities, typically between 0.1 and 10 grams per centimeter. Warm dense fluids like hydrogen, helium, and carbon are believed to make up the interiors of many planets, white dwarfs, and other stars in our universe. The existence of warm dense matter (WDM) on Earth, however, is very rare, as it can only be created with high-energy sources like a nuclear explosion. In such an event, theoretical and computational models that accurately predict the response of certain materials are thus very …

Annual Simulation Of Photovoltaic Retrofits Within Existing Parabolic Trough Concentrating Solar Powerplants, Nipun Goel, Hannah O'Hern, Matthew Orosz, Todd Otanicar

Mechanical and Biomedical Engineering Faculty Publications and Presentations

Solar power for electricity production comes from either photovoltaics or concentrating solar power plants. The former has seen rapid growth and expansion due to the rapid fall in global prices, while the latter has seen moderate growth due to ability to cheaply store thermal energy for later use. Hybridization, or combining photovoltaics with concentrating solar power represents a potential way for lowering cost while enabling long term storage. Over 5 GW of capacity exist worldwide using parabolic trough style technology for concentrating solar power which presents a unique option for optimization in the form of a photovoltaic retrofit. While it …

Thermal Modeling And Analysis Of Roadway Embedded Wireless Power Transfer Modules, Arden N. Barnes

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Wireless charging of electric vehicles is a developing technology which potentially increases efficiency and safety. It also allows for charging vehicles while they are moving by having charging stations embedded in the roadway. Because roadways are thermally insulating, it is important to know how the heat from the charging stations will move through the roadway, which will allow further research into whether the heat will cause damage to the components in the station or to the roadway. This thesis studies the way the heat moves through concrete with wireless charging coils embedded in it. This is accomplished by measuring the …

Development Of Reduced Chemical Kinetic Models For The Numerical Simulation Of Combustion And Emissions Behavior Of Representative Conventional And Bio-Derived Fuels, Mazen A. Eldeeb

Mineta Transportation Institute

The study addresses two of the main challenges facing combustion modeling for transportation fuels: simultaneous simulation of non-related combustion problems and reducing the computational cost of the modeling process itself. To address the first challenge, researchers determine a characteristic flame time from thermal diffusivity and laminar burning velocity. Researchers examine parametric dependence of flame time and ignition delay time on pressure, temperature and equivalence ratio for methane, based on validated chemical kinetic mechanisms. The study reveals flame time and ignition delay time show similar temperature dependence, flame time has stronger dependence on equivalence ratio and weaker dependence on pressure than …

Design For Additive Manufacturing, Michael Charonnat, Leonardo Franco-Muñoz, Sam Noble, J.P. Purdom

Mechanical Engineering

This document outlines the critical design details and timeline for the Design for Additive Manufacturing Senior Project sponsored by Solar Turbines, Inc. The scope of this project encompasses the redesign of two of Solar Turbine’s cast parts for metal additive manufacturing in order to minimize lead time, cost, and weight. With the overall objective of performing in-depth analysis exploring affordability & feasibility, this redesign process will aid Solar Turbines in expanding their knowledge of Design for Additive Manufacturing principles and enable them to further incorporate the use of additive manufacturing into their production processes. The first part that the team …

Discrete Vortex Modeling Of Aerodynamic Flutter Of A Flat Plate With Damped Oscillations, Emma Chao

UNLV Theses, Dissertations, Professional Papers, and Capstones

Aerodynamic flutter is the unstable oscillation of a body caused by the interaction of aerodynamic forces, structural elasticity, and inertial effects induced by vortex shedding. Current models of this phenomenon require finite element analysis and extensive computational power and processing time. The purpose of this study was to develop and validate a program that is faster and more efficient than existing approaches by using the discrete vortex method (DVM). By reducing the complexities of flutter to the shedding of vortices in an inviscid model of a two-dimensional flat plate with a torsional spring constant at its center, this phenomenon can …

Impact Of Magnetocaloric Material Properties On Performance Of A Magnetocaloric Heat Pump., Michael G. Schroeder

Electronic Theses and Dissertations

In the field of magnetocaloric heat pumps much research has been performed around machine design and theoretical machines, but little has been researched around practical problems such as variability in material properties. The present work defines a simulation tool that has been proven with experimental data. Magnetocaloric material cascades were statistically analyzed and parameterized, such that they could be recreated parametrically using a split Lorentz function with normally distributed parameters. Correlated curve-defining values with standard deviations were used as input into the simulation tool to determine the effect of variation on cooling heat pump performance for a household refrigerator application. …

Hybrid Phase-Change Lattice Boltzmann Simulation Of Vapor Condensation On Vertical Subcooled Walls, Wandong Zhao, Yuan Gao, Ruijie Li, Songgang Qiu, Yin Zhang, Ben Xu

Mechanical Engineering Faculty Publications

Saturated vapor condensation on homogenous and heterogeneous subcooled walls is presented in this study by adopting a hybrid phase-change multiple-relaxation-time Lattice Boltzmann model. The effects of wall wettability on the condensation process, including droplets’ growth, coalescence and falling, and the influence of vapor flow to condensation are investigated. The results demonstrate that the heat fluxes around the triple-phase contact lines are higher than that in other cold areas in homogeneous subcooled walls, which actually indicates the fact that filmwise condensation is preventing the continuous condensation process. Furthermore, the dropwise condensation can be formed more easily on the heterogeneous surface with …

Virtual Experiments For Engineering Education, Amy P. Lebanoff

Honors Undergraduate Theses

In-person engineering instruction relies on the availability of equipment and space. Cost, safety, and scheduling may pose barriers to conducting in-person labs. Virtual experiments may be used to enhance the student experience by, for example, incorporating pre-labs for in-person experiments and providing access to equipment that cannot be safely used in-person. Virtual learning is used in many fields, but there remain questions as to how it should be employed in engineering, an area largely reliant on in-person lab and classroom setups. Earlier studies reviewed the advantages of virtual labs such as demonstrating hard-to-observe phenomena and allowing unlimited trials. This project …

Gearbox Baffle Optimization, Megan Arduin

Masters Theses

Current literature reveals there is limited consensus on the placement of baffles within a gearbox to reduce churning losses. Thus, there is a need for a process to identify baffle clearances that result in maximum and minimum churning losses. There are two types of baffles: axial and radial. While both axial and radial baffles cause reductions in churning losses to various degrees, the focus is on the effect of radial baffles. The effect of a board (rectangular plate) baffle location on the churning losses of a single gear gearbox are evaluated using computational fluid dynamics (CFD) implemented in Ansys. Several …

Gesture Based Control Of Semi-Autonomous Vehicles, Brian Sanders

Computational Modeling & Simulation Engineering Theses & Dissertations

The objective of this investigation is to explore the use of hand gestures to control semi-autonomous vehicles, such as quadcopters, using realistic, physics based simulations. This involves identifying natural gestures to control basic functions of a vehicle, such as maneuvering and onboard equipment operation, and building simulations using the Unity game engine to investigate preferred use of those gestures. In addition to creating a realistic operating experience, human factors associated with limitations on physical hand motion and information management are also considered in the simulation development process. Testing with external participants using a recreational quadcopter simulation built in Unity was …

Development Of A Plc-Based Control Systems Trainer Using Open Source Hmi Simulation Software, Nathaniel Bryce Blevins

Student Theses and Dissertations

The integration of an open-source HMI program, AdvancedHMI, into a PLC control systems trainer is discussed in detail. This document assists the reader in understanding the steps required to connect controllers with AdvancedHMI and construct simulated projects. This document is intended to serve as an instructional guide to students, faculty and users. This document outlines and discusses in detail the many tools contained within AdvancedHMI that are necessary to construct simulations for projects. How each tool interacts and is connected to the controller is discussed in detail, including each tools’ applicability to general applications. This document serves as a guide …

Competence Of A Spray Passive Down-Draft Evaporative Cooling (Pdec) System For Space Cooling, Daeho Kang, Richard K. Strand

Publications and Research

A spray PDEC system has been relatively less considered than other passive cooling strategies as one of the viable low-energy solutions in the cooling of buildings while having a great potential in energy savings. This study is intended to evaluate the capability of a spray PDEC system for space cooling. It comprises four simulation scenarios to see the system response and influence of indoor thermal environment when a spray PDEC system is adopted as a primary cooling system in two different climates. The simulation results show that a spray PDEC system causes a substantial variation in the indoor thermal environment …

How Will Climate Alter Efficiency Objectives? Simulated Impact Of Using Recent Versus Historic European Weather Data For The Cost-Optimal Design Of Nearly Zero Energy Buildings (Nzebs), Florida Solar Energy Center, Delia D'Agostino

FSEC Energy Research Center®

Achieving "nearly zero energy buildings" (NZEB) has been established as a vital objective over the next decade within the European Union (EU) [1, 2]. Previous work has shown that a series of very cost-effective thermal efficiency measures, equipment, appliance and renewable energy choices are available across climates to reach the NZEB objective. Resulting detailed energy and economic optimization findings have been obtained and published. One area that has just begun to be explored, however, is how selection of weather files and their application against coming climate change can influence outcomes from energy optimization procedures.

Presented at: CLIMA 2019, REHVA 13th …

Analysis Of The System Response Of A Spray Passive Downdraft Evaporative Cooling System, Daeho Kang, Richard K. Strand

Publications and Research

A spray Passive Downdraft Evaporative Cooling (PDEC) system achieves great savings for space cooling and improves indoor environmental quality by supplying a large amount of fresh outdoor air. As previous studies heavily focused on the energy saving capability of a spray PDEC system due to lack of methods for a detailed analysis, the influence of cool humid supply air from a spray PDEC system in a space in buildings has not been comprehensively studied. This study is intended to evaluate the competence of a spray PDEC system as a primary cooling system in typical spaces in a primary school building …

Modeling Of Complex Parts For Industrial Waterjet Cleaning, Braden James

Graduate Theses and Dissertations

Industrial high-pressure waterjet cleaning is common to many industries. The modeling in this paper functions inside a collaborative robotic framework for high mix, low volume processes where human robot collaboration is beneficial. Automation of pressure washing is desirable for economic and ergonomic reasons. An automated cleaning system needs path simulation and analysis to give the operator insight into the predicted cleaning performance of the system. In this paper, ablation, the removal of a substrate coating by waterjet, is modeled for robotic cleaning operations. The model is designed to work with complex parts often found in spray cleaning operations, namely parts …

Cfd Study Of Aerodynamic Drag Reduction Tool Of A Generic Sports Utility Vehicle (Suv), Samira Ishrat Jahan

Masters Theses

The Sports Utility Vehicle (SUV) has been a popular automobile choice in North America for over 50 years due to its seating and hauling versatility and good towing capacity. This widespread popularity has resulted in manufacturers pushing for increased horsepower and cabin size. Unfortunately, the limiting factor has been fuel economy which is governed by the vehicle aerodynamics. A reduction in aerodynamic drag can result in better fuel economy. The goal of this study is to reduce the aerodynamic drag of a generic SUV and the efficient application of drag reduction devices to control flow separation. An initial study has …

Exergetic Relationship Between The Thermal Properties Of Direct Contact Membrane Distillation, D. Perdue, L. Chen, L. Schaefer

Publications

Direct contact membrane distillation (DCMD) is a process that has shown promise within the field of desalination due to its less energy intensive methods and widespread applications. DCMD is a thermally driven microfiltration separation process that operates on the principle of vapor–liquid equilibrium conditions where heat and mass transfer occur simultaneously. Fundamentally, DCMD is based on a porous hydrophobic membrane separating the hot solution (feed) from the cold solution (permeate) where desalinated water condenses. The membrane interfacial temperatures determine the vapor pressure difference across the membrane. In this work, a direct simulation Monte Carlo analysis is employed to investigate how …

Experiment And Computational Analysis On Effect Of Plasma Actuation Incompressible Flow Around Tandem Cylinders, Emmanuel C. Gabriel-Ohanu

Honors Undergraduate Theses

The utilization of steady state flow of air over tandem circular cylinders has several applications in engineering systems. Incompressible flow over circular cylinders in tandem at different spacing with and without plasma actuation on the leading cylinder will be investigated in this paper to understand the effects of plasma actuation on flow properties and wake region of the two cylinders in cross flow. The principal focus of the research is on the use of experimental and computational methods to study and provide valid results, the research will analyze the wake region, the effect of Reynolds number and the longitudinal spacing …

Simulation Of Lubricant For Design Of Magnetic Recording Systems Under Laser Heating, Ryan Hetzel, Shao Wang Dr., Jonathon Lawry, Ahmed Alsafwani

Williams Honors College, Honors Research Projects

Heat assisted magnetic recording is an advanced technology which can enable storage density increase in next generation hard disk drive. These drives are implemental in server (cloud) storage and the storage of large projects such as the Event Horizon Telescope which recently captured images of a black hole. The data is written on the magnetic surface by means of laser heating. The coercivity of magnetic medium is reduced by heating surface and within heating period data is written on disk. During the heating process, lubricant present on the disk might evaporate because of high temperature of laser and can accumulate …

A Framework For Energy Optimization Of Small, Two-Stroke, Natural Gas Engines For Combined Heat And Power Applications, Mahdi Darzi

Graduate Theses, Dissertations, and Problem Reports (ETD)

This research was focused on the development of a framework for the energy optimization a natural gas engine for small combined heat and power (CHP) applications operating with low-pressure natural gas (NG) available at homes. The required targets of the ARPA-E GENSETS program for 1 kW electric power generation and previous GENSETS simulation at West Virginia University, suggested a design space for the engine which is currently dominated by simple two-stroke designs. Hence this research focused on screening, modeling, and experimentally evaluation of cost-effective technologies to achieve a system design that maximized thermal efficiency and utilization factor, while reducing emissions. …

A Transfer Matrix Model Of The Iec 60318-4 Ear Simulator: Application To The Simulation Of Earplug Insertion Loss, Yu Luan, Franck Sgard, Simon Benacchio, Hugues Nélisse, Olivier Doutres

Études primaires

The IEC 60318-4 ear simulator is used to measure the insertion loss (IL) of earplugs in the ear canal of an acoustical test fixture (ATF) and is designed to represent an average acoustic impedance (in a reference plane) of the human ear. The ear simulator is usually modeled using a lumped parameter model (LPM) which has frequency limitations and inadequately accounts for the thermo-viscous effects in the simulator. The simulator numerical models that can better deal with the thermo-viscous phenomena often lack essential geometric details. Most related studies also suffer from the lack of experimental validation of the models. Therefore, …

Cfd Modeling Of Smoke Movement In An Atrium, Robin Wu

UNLV Theses, Dissertations, Professional Papers, and Capstones

The purpose of this paper is to better understand the behavior of smoke movement in an atrium. Thus gives first responders and civilians in and out of building a better understanding

With the advancements of modern technology, computers and softwares make simulation models possible such as fire models to simulate fire and smoke movements. In this paper, a computational fluid dynamic (CFD) software Fire Dynamic Simulator (FDS) is used to conduct a series of atrium tests to investigate the effectiveness of smoke exhaust systems. FDS solves the Navier-Stokes equations appropriate for low speed flows (Ma < 0.3) with an emphasis on smoke, heat transport and CO2 concentrations from fires. The default turbulence model used in FDS simulation is the Large Eddy Simulation (LES), which is the solution of Navier-Stokes equations at low speed.

The compartment tested was 9 …