Fluid Dynamics Commons^™

Implementation Of Fast Hydraulic Erosion Simulation And Visualization On Gpu, Brian Hawkins

Computer Science Graduate Research Workshop

No abstract provided.

Dispersive Hydrodynamics In Viscous Fluid Conduits, Michelle Maiden

Applied Mathematics Graduate Theses & Dissertations

Viscous fluid conduits provide an ideal system for the study of dissipationless, dispersive hydrodynamics. A dense, viscous fluid serves as the background medium through which a lighter, less viscous fluid buoyantly rises. If the interior fluid is continuously injected, a deformable pipe forms. The long wave interfacial dynamics are well-described by a dispersive nonlinear partial differential equation called the conduit equation.

Experiments, numerics, and asymptotics of the viscous fluid conduit system will be presented. Structures at multiple length scales are characterized, including solitary waves, periodic waves, and dispersive shock waves. A more generic class of large-scale disturbances is also studied ...

High Throughput, Automated Prediction Of Focusing Patterns For Inertial Microfluidics, Aditya Kommajosula, Jeong-Ah Kim, Wonhee Lee, Baskar Ganapathysubramanian

Mechanical Engineering Publications

Visual inspections for identifying focusing points in inertial microfluidic flows are prone to misinterpreting stable locations and focusing shifts in the case of non-trivial focusing patterns. We develop and deploy an approach for automating the calculation of focusing patterns for a general channel geometry, and thereby reduce the dependence on empirical/visual procedures to confirm the presence of stable locations. We utilize concepts from interpolation theory (to represent continuous force-fields using discrete points), and stability theory to identify "basins of attraction" and quantitatively identify stable equilibrium points. Our computational experiments reveal that predicting equilibrium points accurately requires upto ×10-20 times ...

Shape-Design For Stabilizing Micro-Particles In Inertial Microfluidic Flows, Aditya Kommajosula, Daniel Stoecklein, Dino Di Carlo, Baskar Ganapathysubramanian

Mechanical Engineering Publications

Design of microparticles which stabilize at the centerline of a channel flow when part of a dilute suspension is examined numerically for moderate Reynolds numbers (10≤Re≤80). Stability metrics for particles with arbitrary shapes are formulated based on linear-stability theory. Particle shape is parametrized by a compact, Non-Uniform Rational B-Spline (NURBS)-based representation. Shape-design is posed as an optimization problem and solved using adaptive Bayesian optimization. We focus on designing particles for maximal stability at the channel-centerline robust to perturbations. Our results indicate that centerline-focusing particles are families of characteristic "fish"/"bottle"/"dumbbell"-like shapes, exhibiting fore-aft asymmetry. A ...

Call For Abstracts - Resrb 2019, July 8-9, Wrocław, Poland, Wojciech M. Budzianowski

Wojciech Budzianowski

No abstract provided.

Investigation Of Flow Disturbances And Multi-Directional Wall Shear Stress In The Stenosed Carotid Artery Bifurcation Using Particle Image Velocimetry, Amanda L. Dicarlo

Electronic Thesis and Dissertation Repository

Hemodynamics and shear forces are associated with pathological changes in the vascular wall and its function, resulting in the focal development of atherosclerosis. Flow complexities that develop in the presence of established plaques create environments favourable to thrombosis formation and potentially plaque rupture leading to stroke. The carotid artery bifurcation is a common site of atherosclerosis development. Recently, the multi-directional nature of shear stress acting on the endothelial layer has been highlighted as a risk factor for atherogenesis, emphasizing the need for accurate measurements of shear stress magnitude as well direction. In the absence of comprehensive patient specific datasets numerical ...

Heat Transfer Comparison Of Varied Pebble Sizes And Packing Arrangements In A Pebble-Bed Reactor, Julian Spangler

Georgia Undergraduate Research Conference (GURC)

Pebble bed reactors are more cost efficient when heat transfer is optimized. In a pebble-bed reactor, optimizing heat transfer involves the analysis of complex flow. Therefore, computational fluid dynamics was used to simulate fluid movement in a structured cubic packing arrangement with a purpose in finding an optimal size of pebbles that will yield the fastest rate of heat transfer. The simple cubic pebble arrangement was used to determine if pebble size was key to optimizing heat transfer in the reactor. More complex arrangements of pebbles were used as comparison to the simple cubic packing in order to determine if ...

Entry Of A Sphere Into A Water-Surfactant Mixture And The Effect Of A Bubble Layer, Nathan Speirs, Mohammad Mansoor, Randy Hurd, Saberul Sharker, W. G. Robinson, B. J. Williams, Tadd T. Truscott

Mechanical and Aerospace Engineering Faculty Publications

A rigid sphere entering a liquid bath does not always produce an entrained air cavity. Previous experimental work shows that cavity formation, or the lack thereof, is governed by fluid properties, wetting properties of the sphere, and impact velocity. In this study, wetting steel spheres are dropped into a water-surfactant mixture with and without passing through a bubble layer first. Surprisingly, in the case of a water-surfactant mixture without a bubble layer, the critical velocity for cavity formation becomes radius dependent. This occurs due to dynamic surface tension effects, with the local surface tension in the splash increasing during surface ...

Fluted Films, Nathan B. Speirs, Mohammad M. Mansoor, Jesse Belden, Randy C. 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 ...

Experimental Measurements Of Human Cough Airflows From Healthy Subjects And Those Infected With Respiratory Viruses, Nicholas Dudalski

Electronic Thesis and Dissertation Repository

Research concerning person-to-person respiratory virus transmission is required to develop reliable, evidence-based infection prevention and control measures. Experimental studies of human coughs were comprehensively critiqued from the point of view of methodologies, aerodynamics, droplet dispersion and virology. Particle image velocimetry (PIV) and hot-wire anemometry (HWA) measurements were conducted at x=1 m away from the mouth of human subjects to develop a model for cough flow behaviour at greater distances from the mouth than those studied previously. Experiments were conducted for sick subjects who had presented with influenza-like illness, together with a cohort of healthy subjects. Biological aerosol sampling was ...

Reversible Motion In A Contact Line, Audrey Profeta, Esmeralda Orozco, Juan A. Ortiz Salazar, Dani Medina, Nathan C. Keim

STAR (STEM Teacher and Researcher) Presentations

When a body of liquid sits on a surface, an irregular border between the wet and dry regions of the surface exists, called the contact line. Driving this contact line back and forth repeatedly can change its shape.We use a syringe pump to cyclically infuse and withdraw a predetermined volume of water, and take photos of the contact line after each cycle. Comparing these images to each other determines if the contact line is returning to the same shape. We find that below a critical value of infused volume, after many cycles the contact line reaches a steady state ...

The Periglacial Landscape Of Mars: Insight Into The 'Decameter-Scale Rimmed Depressions' In Utopia Planitia, Arya Bina

Electronic Thesis and Dissertation Repository

Currently, Mars appears to be in a ‘frozen’ and ‘dry’ state, with the clear majority of the planet’s surface maintaining year-round sub-zero temperatures. However, the discovery of features consistent with landforms found in periglacial environments on Earth, suggests a climate history for Mars that may have involved freeze and thaw cycles. Such landforms include hummocky, polygonised, scalloped, and pitted terrains, as well as ice-rich deposits and gullies, along the mid- to high-latitude bands, typically with no lower than 20o N/S. The detection of near-surface and surface ice via the Phoenix lander, excavation of ice via recent impact cratering ...

Stability Of The Interface Between Two Immiscible Liquids During Injection Into A Tapered Hele-Shaw Cell, Zihao Lin, Ivan C. Christov, Daihui Lu

The Summer Undergraduate Research Fellowship (SURF) Symposium

In the early twentieth century, petroleum and mining engineers noticed that water does not displace oil uniformly. This phenomenon, when water penetrates through oil, is now known as viscous fingering. This discovery and the following extensive research have contributed to enhancing oil recovery. In this paper, we describe a numerical study conducted on the stability of the interface between two immiscible liquids in converging and diverging Hele-Shaw cells with varying gradients. Hele-Shaw cells are narrow flow geometries that mimic the properties of a porous medium with fixed permeability. By using computational tools built on the OpenFOAM platform, the multiphase flow ...

Fuel Flow Reduction Impact Analysis Of Drag Reducing Film Applied To Aircraft Wings, Damon Resnick, Chris Donlan, Nimish Sakalle, Cody Pinkerman

SMU Data Science Review

In this paper, we present an analysis of flight data in order to determine whether the application of the Edge Aerodynamix Conformal Vortex Generator (CVG), applied to the wings of aircraft, reduces fuel flow during cruising conditions of flight. The CVG is a special treatment and film applied to the wings of an aircraft to protect the wings and reduce the non-laminar flow of air around the wings during flight. It is thought that by reducing the non-laminar flow or vortices around and directly behind the wings that an aircraft will move more smoothly through the air and provide a ...

Electro-Drop Bouncing In Low-Gravity, Erin Stivers Schmidt

Dissertations and Theses

We investigate the dynamics of spontaneous jumps of water drops from electrically charged superhydrophobic dielectric substrates during a sudden step reduction in gravity level. In the brief free-fall environment of a drop tower, with a non-homogeneous external electric field arising due to dielectric surface charges (with surface potentials 0.4-1.8 kV), body forces acting on the jumped drops are primarily supplied by polarization stress and Coulombic attraction instead of gravity. This electric body force leads to a drop bouncing behavior similar to well-known phenomena in 1-g₀, though occurring for much larger drops (~0.5 mL). We show ...

Determining The Activation Energy Of Glucose Syrup Using The Arrhenius Equation, Utkarsh Sharma

The International Student Science Fair 2018

This experiment finds the activation energy of corn syrup using the Arrhenius equation. This was done through a simple experiment of dropping a ball into corn syrup and measuring its terminal velocity. From this, the viscosity could be derived, through the use of rearrangement of Newton’s First Law. The temperature of the corn syrup was also varied through the use of a microwave by raising it to 50 degrees Celsius. It is known that the more viscous a liquid is, the greater the activation energy for the liquid, which is essentially the energy barrier that a molecule has to ...

Finding Activation Energy Of Corn Syrup, Utkarsh Sharma

The International Student Science Fair 2018

This experiment finds the activation energy of corn syrup using the Arrhenius equation. This was done through a simple experiment of dropping a ball into corn syrup and measuring its terminal velocity. From this, the viscosity could be derived, through the use of rearrangement of Newton’s First Law. The temperature of the corn syrup was also varied through the use of a microwave by raising it to 50 degrees Celsius. It is known that the more viscous a liquid is, the greater the activation energy for the liquid, which is essentially the energy barrier that a molecule has to ...

Computer Design Of Microfluidic Mixers For Protein/Rna Folding Studies, Venkatesh Inguva, Sagar V. Kathuria, Osman Bilsel, Blair James Perot

Open Access Articles

Kinetic studies of biological macromolecules increasingly use microfluidic mixers to initiate and monitor reaction progress. A motivation for using microfluidic mixers is to reduce sample consumption and decrease mixing time to microseconds. Some applications, such as small-angle x-ray scattering, also require large ( > 10 micron) sampling areas to ensure high signal-to-noise ratios and to minimize parasitic scattering. Chaotic to marginally turbulent mixers are well suited for these applications because this class of mixers provides a good middle ground between existing laminar and turbulent mixers. In this study, we model various chaotic to marginally turbulent mixing concepts such as flow turning, flow ...

Elementary Computational Fluid Dynamics Using Finite-Difference Methods, Jason Turner, Scott Labrake

Honors Theses

Fluids permeate all of human existence, and fluid dynamics serves as a rich field of research for many physicists. Although the mathematics involved in studying fluids tends to get complicated, the physical intuition gained through daily exposure to such systems bridges the gap between abstract calculations and their physical meaning. We discuss the mathematical treatment and simulations of fluid flows found in everyday life, such as flow in a cavity and through a pipe. Our discussions follow the example set by several notable texts, referenced in the document.