Fluid Dynamics Commons^™

Electroosmotic Flow Of Viscoelastic Fluid Through A Constriction Microchannel, Jianyu Ji, Shizhi Qian, Zhaohui Liu

Mechanical & Aerospace Engineering Faculty Publications

Electroosmotic flow (EOF) has been widely used in various biochemical microfluidic applications, many of which use viscoelastic non-Newtonian fluid. This study numerically investigates the EOF of viscoelastic fluid through a 10:1 constriction microfluidic channel connecting two reservoirs on either side. The flow is modelled by the Oldroyd-B (OB) model coupled with the Poisson–Boltzmann model. EOF of polyacrylamide (PAA) solution is studied as a function of the PAA concentration and the applied electric field. In contrast to steady EOF of Newtonian fluid, the EOF of PAA solution becomes unstable when the applied electric field (PAA concentration) exceeds a critical value for …

Nebulizer-Based Systems To Improve Pharmaceutical Aerosol Delivery To The Lungs, Benjamin M. Spence

Theses and Dissertations

Combining vibrating mesh nebulizers with additional new technologies leads to substantial improvements in pharmaceutical aerosol delivery to the lungs across therapeutic administration methods. In this dissertation, streamlined components, aerosol administration synchronization, and/or Excipient Enhanced Growth (EEG) technologies were utilized to develop and test several novel devices and aerosol delivery systems. The first focus of this work was to improve the poor delivery efficiency, e.g., 3.6% of nominal dose (Dugernier et al. 2017), of aerosolized medication administration to adult human subjects concurrent with high flow nasal cannula (HFNC) therapy, a form of continuous-flow non-invasive ventilation (NIV). The developed Low-Volume Mixer-Heater (LVMH) …

Thermo-Fluid Characterizations Of The Powder-Bed Fusion Additive Manufacturing Processes Using Laser And Electron Beam, M Shafiqur Rahman

LSU New Orleans Theses and Dissertations

The powder-bed fusion (PBF) process is a subdivision of Additive Manufacturing (AM) technology where a heat source at a controlled speed selectively fuses regions of a powder-bed material to form three-dimensional (3-D) parts. Two of the most effective PBF processes are selective laser melting (SLM) and electron beam additive manufacturing (EBAM), which can fabricate full-density metallic parts in a layer-by-layer fashion. In this study, thermal behavior and melt-pool dynamics in the PBF process are investigated by developing 3-D multiphysics-based thermo-fluid models for both SLM and EBAM, containing Ti-6Al-4V alloy as a powder-bed material. The laser and electron beams are modeled …

Understanding Of Aerosol Transmission Of Covid 19 In Indoor Environments, Adama Barro, Cathal O'Toole, Jacob S. Lopez, Matthew Quinones, Sherene Moore

Publications and Research

Our reason for discussing severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) or 2019 novel corona virus (Covid-19), is to understand its aerosol transmission characteristics in indoor spaces and to mitigate further spread of this disease by designing a new HVAC system. The problem that we are tackling is the spread of covid-19 droplets through aerosol transmission by looking at potential engineering solutions to the existing HVAC systems. The purpose is to eradicate the spread of the COVID-19 by testing indoor spaces in an effort to understand the effectiveness of ventilation controls. We believe that scientists and engineers have not …

Feasibility Of Electric Field Assisted Clogging Reduction In Cold Gas Spraying Nozzle, Hendric Tronsson

ENGS 88 Honors Thesis (AB Students)

The relatively novel cold spraying process expands its range of applications constantly. In order to continue this trend, this process still has various hurdles that need to be overcome such as clogging. Clogging within the cold gas spraying process causes porous coatings with less material properties and lower durability; a solution is needed in order to reduce the clogging and so expand the cold gas spraying applications. This study aimed to explore the feasibility of using an electric field to reduce clogging. To do so a simplified channel was used to simulate charged particle trajectory shifts under the influence of …

Study Of Heat And Momentum Transfer To Colloidal Suspensions In Annular Closed Conduit Flow, Sadik Shoaib

Student Works (2020-2029)

With the advancement of science and the rapid growth of industries and the improved lifestyles of people, energy consumption has been increasing. Whereas the exploration of energy remained at a slower pace and the energy reservoirs are extinguishing at a faster rate. High energy consumption is also encouraging environmental pollution and global warming. Considering all these issues, scientists and engineers are desperately exploring highly efficient heat exchangers for the conservation of energy and minimize its losses. The present research has focused on obtaining highly efficient heat exchangers. Lots of research have performed on the improvement of heat exchanger materials, alteration …

Synthesis Of Eco-Friendly Nanofluids For Enhancement Of Heat Transfer And Application In Different Flow Configuration Passages, Khan Asif

Student Works (2020-2029)

Since the invention of the heat exchangers, the working fluids such as water, ethyl glycol, oil and many others were used, however, they reveal relatively low thermal conductivity. Eco-friendly nanofluids and the cost-effective annular heat exchangers were introduced in this research to overcome the problem. In the present work, heat transfer coefficient and friction loss analyses of (TiO2 and GNP) water-based nanofluids were compared with DI-water flowing in annular conduit under turbulent flow regime. The nanoparticle weight concentrations of 0.1, 0.075, 0.05 and 0.025 wt.% were prepared by using a simple two-step method. The DI-water simulations were conducted by using …

Computational Analysis Of A New Planar Mixing Layer Flame Configuration To Study Soot Inception, Carmen Ciardiello

Honors Scholar Theses

The production of soot is omnipresent in society today. Soot is the product of many of the combustion processes that provide the bulk of the usable energy throughout the world. Furthermore, soot particulate poses a great danger to both the environment and all forms of life on Earth. It has proven to pollute ecosystems, foster health problems for human beings, and degrade air quality [1].

These dangers make studying and understanding soot particulate paramount for improving the quality of life. Thus, this study introduces a new flame configuration for studying soot inception. Presently, various common flame configurations have been found …

Computational Fluid Dynamics Study Of The Effects Of Secondary Flows In 90-Degree Pipe Elbow Erosion, O. Ayala, G. Rivera-Hernández, C. Knight

Engineering Technology Faculty Publications

Computational fluid dynamics (CFD) of particle-laden fluid flows through a 90-degree pipe elbow at Reynolds numbers 1,000 and 10,000 were completed; for different dimensionless elbow curvature ratios of 1.0, 1.5, and 2.5; and for particles with different Stokes numbers of 0.01, 0.1, 0.5, 1.0, 5.0, and 10.0. There were two scenarios in the study. For the first, the particles felt drag from the primary (or the axial) flow as well as from the secondary fluid flows in the elbow. For the second, the secondary fluid flow in the 90-degree bend was suppressed from the particle drag, thus the particles only …

Magnetic Control Of Transport Of Particles And Droplets In Low Reynolds Number Shear Flows, Jie Zhang

Doctoral Dissertations

“Magnetic particles and droplets have been used in a wide range applications including biomedicine, biological analysis and chemical reaction. The manipulation of magnetic microparticles or microdroplets in microscale fluid environments is one of the most critical processes in the systems and platforms based on microfluidic technology. The conventional methods are based on magnetic forces to manipulate magnetic particles or droplets in a viscous fluid.

In contrast to conventional magnetic separation method, several recent experimental and theoretical studies have demonstrated a different way to manipulate magnetic non-spherical particles by using a uniform magnetic field in the microchannel. However, the fundamental mechanism …

A Cfd Study Of Steady Fully Developed Laminar Flow Through A 90-Degree Bend Pipe With A Square Cross-Sectional Area, Subodh Sushant Toraskar

Mechanical & Aerospace Engineering Theses & Dissertations

Fluid flow through a closed curved conduit has always been a topic of extensive research, as it has many practical and industrial applications. The flow is generally characterized by a presence of secondary flow, vortical motions and pressure losses for different flow regimes. These observed irregularities may positively or negatively impact the flow. They are beneficial for cases where mixing of fluids is required, usually observed for multiphase flow regimes or detrimental for cases involving particles in the fluid. There are also instances where a particle-laden fluid transported through the curved pipe was directly related to corrosion- erosion related problems. …

Characterization Of Single- And Multi-Phase Shock-Accelerated Flows, Patrick John Wayne

Mechanical Engineering ETDs

Experiments conducted in the Shock Tube Facility at the University of New Mexico are focused on characterization of shock-accelerated flows. Single-phase (gaseous) initial conditions consist of a heavy gas column of sulfur hexafluoride seeded with approximately 11% acetone gas by mass. Visualization of the image plane for gaseous initial conditions is accomplished via planar laser-induced fluorescence (PLIF) with a high-powered Nd:YAG ultraviolet laser and an Apogee Alta U-42 monochrome CCD camera, with a quantum efficiency > 90%. Multi-phase (gas-solid) initial conditions consist of glass micro-beads deposited on small 1-cm diameter discs of specific surface chemistry, mounted flush with the bottom wall …

A Soft-Robotic Harbor Porpoise Pectoral Fin Driven By Coiled Polymer Actuators As Artificial Muscles, Robert Hunt, Sarah Trabia, Zakai Olsen, Kwang Kim

Mechanical Engineering Faculty Research

Biomimicry is an approach in science and engineering to overcome human challenges by designing materials and systems modeled after nature. Selected applications of biomimicry include catheters, hearing devices, and artificial appendages such as arms, legs, and fingers. The inspiration for this study is the hydrofoil-like structured pectoral fin of the harbor porpoise whale that is ultimately useful for studying fluid-structure interactions, drag, lift, and laminar-to-turbulent transitions. The pectoral fin is fabricated by manipulating computed tomography (CT) scans into 3D models using Simpleware ScanIP and post-processed in Autodesk for printing. An array of thermally driven coiled polymer actuators (CPA) fabricated from …

Geospatial Energy Potential And Life Cycle Assessment Of Nearshore Oscillating Water Column Systems, Aleks Siemenn, Marie-Odile Fortier

CURCE Annual Undergraduate Conference

Oscillating Water Column (OWC) systems are an iteration of terminator ocean energy technology which generate electrical energy from turbine torque induced by the compression of air in a chamber from changing water level height. OWCs are a well-established technology, however, there have been no studies to date which quantify the life cycle environmental impacts of these systems in a geographic context. The goal of this study is to optimally size an OWC system for selected New England coastline sites and then assess the environmental impacts of the varying system sizes.

An OWC system is optimally sized when the volume of …

Examination Of Flow Dynamics And Passive Cooling In An Ultra Compact Combustor, Tylor C. Rathsack

Theses and Dissertations

The Ultra Compact Combustor (UCC) promises to greatly reduce the size of a gas turbine engine’s combustor by altering the manner in which fuel is burnt. Differing from the common axial flow combustor, the UCC utilizes a rotating flow, coaxial to the engine’s primary axis, in an outboard circumferential cavity as the primary combustion zone. The present study investigates two key UCC facets required to further this combustor design. The first area of investigation is cooling of the Hybrid Guide Vane (HGV). This UCC specific hardware acts as a combustor center body that alters the exit flow angle and acts …

A Study Of Several Applications Of Parallel Computing In The Sciences Using Petsc, Nicholas Stegmeier

Electronic Theses and Dissertations

The importance of computing in the natural sciences continues to grow as scientists strive to analyze complex phenomena. The dynamics of turbulence, astrophysics simulations, and climate change are just a few examples where computing is critical. These problems are computationally intractable on all computing platforms except supercomputers, necessitating the continued development of efficient algorithms and methodologies in parallel computing. This thesis investigates the use of parallel computing and mathematical modeling in the natural sciences through several applications, namely computational fluid dynamics for impinging jets in mechanical engineering, simulation of biofilms in an aqueous environment in mathematical biology, and the solution …

Optimization And Control Of Arrays Of Wave Energy Converters, Jianyang Lyu

Dissertations, Master's Theses and Master's Reports

Wave Energy Converter Array is a practical approach to harvest ocean wave energy. To leverage the potential of the WEC array in terms of energy extraction, it is essential to have a properly designed array configuration and control system. This thesis explores the optimal configuration of Wave Energy Converters (WECs) arrays and their optimal control. The optimization of the WEC array allows both dimensions of individual WECs as well as the array layout to varying. In the first optimization problem, cylindrical buoys are assumed in the array where their radii and drafts are optimization parameters. Genetic Algorithms are used for …

Fluted Films, Nathan B. Spiers, Mohammad M. Mansoor, Jesse Belden, Randy Craig Hurd, Zhao Pan, Tadd T. Truscott

Mechanical and Aerospace Engineering Faculty Publications

This paper is associated with a poster winner of a 2017 APS/DFD Milton van Dyke Award for work presented at the DFD Gallery of Fluid Motion. The original poster is available from the Gallery of Fluid Motion, https://doi.org/10.1103/APS.DFD.2017.GFM.P0030

Interface Model Of Pem Fuel Cell Membrane Steady-Dtate Behavior, Russell L. Edwards, Ayodeji Demuren

Mechanical & Aerospace Engineering Faculty Publications

Modeling works which simulate the proton-exchange membrane fuel cell with the computational fluid dynamics approach involve the simultaneous solution of multiple, interconnected physics equations for fluid flows, heat transport, electrochemical reactions, and both protonic and electronic conduction. Modeling efforts vary by how they treat the physics within and adjacent to the membrane-electrode assembly (MEA). Certain approaches treat the MEA not as part of the computational domain, but rather an interface connecting the anode and cathode computational domains. These approaches may lack the ability to consistently model catalyst layer losses and MEA ohmic resistance. This work presents an upgraded interface formulation …

Wind Energy And Wind-Energy-Inspired Turbulent Wakes: Modulation Of Structures, Mechanisms And Flow Regimes, Elizabeth H. Camp

Dissertations and Theses

The interaction of turbulent wakes with one another and with the adjacent fluid directly impacts the generation of electricity in wind turbine arrays. Computational modeling is well suited to the repeated iterations of data generation that may be required to inform understanding of the function of wind farms as well as to develop control schemes for plant function. In order to perform such computational studies, a simplified model of the turbine must be implemented. One of the most computationally efficient parametrizations of the blade utilizes a stationary disk which has a prescribed drag and produces a wake. However, since accurate …

Risk Assessment Of Dropped Cylindrical Objects In Offshore Operations, Adelina Steven

LSU New Orleans Theses and Dissertations

Dropped object are defined as any object that fall under its own weight from a previously static position or fell due to an applied force from equipment or a moving object. It is among the top ten causes of injuries and fatality in oil and gas industry. To solve this problem, several in-house tools and guidelines is developed over time to assess the risk of dropped objects on the sub-sea structures. This thesis focuses on compiling and comparing those methods in hope to improve the recommended practices available in the market. A simple modification is done on the in-house tools …

Experimental Examination Of Vorticity Stripping From A Wing-Tip Vortex In Free-Stream Turbulence, Hari C. Ghimire, Sean C. C. Bailey

Mechanical Engineering Faculty Publications

Time-resolved stereoscopic particle image velocimetry measurements were conducted of a wing-tip vortex decaying in free-stream turbulence. The objective of the research was to experimentally investigate the mechanism causing the increased rate of decay of the vortex in the presence of turbulence. It was observed that the circulation of the vortex core experienced periods of rapid loss and recovery when immersed in free-stream turbulence. These events were not observed when the vortex was in a laminar free stream. A connection was made between these events and distortion of the vortex, coinciding with stripping of core fluid from the vortex core. Specifically, …

Electroosmotic Flow Of Viscoelastic Fluid In A Nanoslit, Lanju Mei, Hongna Zhang, Hongxia Meng, Shizhi Qian

Mechanical & Aerospace Engineering Faculty Publications

The electroosmotic flow (EOF) of viscoelastic fluid in a long nanoslit is numerically studied to investigate the rheological property effect of Linear Phan-Thien-Tanner (LPTT) fluid on the fully developed EOF. The non-linear Poisson-Nernst-Planck equations governing the electric potential and the ionic concentration distribution within the channel are adopted to take into account the effect of the electrical double layer (EDL), including the EDL overlap. When the EDL is not overlapped, the velocity profiles for both Newtonian and viscoelastic fluids are plug-like and increase sharply near the charged wall. The velocity profile resembles that of pressure-driven flow when the EDL is …

Automated Cfd Optimization To Maximize Wind Farms Performance And Land Use, Rafael Valotta Rodrigues

Electronic Theses and Dissertations

In this research, a computational system was designed to analyze and optimize the layout of wind farms under variable operational conditions. At first, a wind turbine computational fluid dynamic (CFD) model was developed covering the near wake. The near wake flow field was validated against near wake velocity data from the MEXICO experiment. The CFD simulation demonstrated that the tip speed ratio and the pitch angle greatly influence the near wake behavior, affecting the velocity deficit and the turbulence intensity profile in this region. The CFD model was extended to cover the far wake, aiming to become a computational tool …

Characterization Of Rotary Bell Atomizers Through Image Analysis Techniques, Jacob E. Wilson

Theses and Dissertations--Mechanical and Aerospace Engineering

Three methods were developed to better understand and characterize the near-field dynamic processes of rotary bell atomization. The methods were developed with the goal of possible integration into industry to identify equipment changes through changes in the primary atomization of the bell. The first technique utilized high-speed imaging to capture qualitative ligament breakup and, in combination with a developed image processing technique and PIV software, was able to gain statistical size and velocity information about both ligaments and droplets in the image data. A second technique, using an Nd:YAG laser with an optical filter, was used to capture size statistics …

Universality Of Local Dissipation Scales In Turbulent Boundary Layer Flows With And Without Free-Stream Turbulence, Sabah F. H. Alhamdi, Sean C. C. Bailey

Mechanical Engineering Faculty Publications

Measurements of the small-scale dissipation statistics of turbulent boundary layer flows with and without free-stream turbulence are reported for Re_τ ≈ 1000 (Re_θ ≈ 2000). The scaling of the dissipation scale distribution is examined in these two boundary conditions. Results demonstrated that the local large-scale Reynolds number based on the measured longitudinal integral length scale fails to properly normalize the dissipation scale distribution near the wall in these two free-stream conditions due to the imperfect characterization of the upper bound of the inertial cascade by the integral length scale. A surrogate found from turbulent kinetic energy and …

Evaluation And Enhancement Of Clean Energy Systems: Analytical, Computational And Experimental Study Of Solar And Nuclear Cycles, Nima Fathi

Mechanical Engineering ETDs

Clean (and specifically renewable) energy is steadily improving its global share. However, finite availability of fossil fuels and the growing effects of climate change make it an urgent priority to convince the industry and governments to incentivize investment in the renewable energy field and to make it more attractive by decreasing the capital cost. Until recently, uncertainties in funding limited renewable energy development, especially in the US. That limitation has been one of the barriers to progress. Another limitation of many renewable energy systems is the variability in their output, which makes them unsuitable for baseline power production. Therefore, fossil …

Characterization Of The Shock Wave Structure In Water, Emilie Teitz

Master's Theses (2009 -)

The scientific community is interested in furthering the understanding of shock wave structures in water, given its implications in a wide range of applications; from researching how shock waves penetrate unwanted body tissues to studying how humans respond to blast waves. Shock wave research on water has existed for over five decades. Previous studies have investigated the shock response of water at pressures ranging from 1 to 70 GPa using flyer plate experiments. This report differs from previously published experiments in that the water was loaded to shock pressures ranging from 0.36 to 0.70 GPa. The experiment also utilized tap …

An Experimental Investigation Of Wing-Tip Vortex Decay In Turbulence, Hai G. Ghimire, Sean C. C. Bailey

Mechanical Engineering Faculty Publications

Particle image velocimetry measurements were conducted for a wing-tip vortex decaying in free-stream turbulence. The vortex exhibited stochastic collapse with free-stream turbulence present, with the breakdown initiating earlier for higher levels of turbulence. An increased rate of decay of the vortex tangential velocity was also observed, increasing with increasing free-stream turbulence. The decay of the vortex tangential velocity without the free-stream turbulence was well represented by viscous diffusion, resulting in an increase in the core radius and decrease in the peak tangential velocity. With the addition of free-stream turbulence, the rate of decay of the peak tangential velocity of the …

Optimizing Jets For Wake Control Of Ground Vehicles, Domenic Barsotti, Sandra Boetcher

Publications

A system of wake control for a ground vehicle to help promote increased fuel efficiencies of the ground vehicle by modifying an air flow wake generated during the movement of the vehicle in a forward direction. The system includes at least one slot jet configured to be located along a rear profile portion of the ground vehicle. The at least one slot jet is configured to provide a continuous flow of air at a non-zero velocity when the ground vehicle is moving in a forward direction, the non-zero velocity being at least partially directed in a rearward direction with an …