Year-2 Progress Report On Numerical Methods For Bgk-Type Kinetic Equations, 2024 University of Tennessee, Knoxville

#### Year-2 Progress Report On Numerical Methods For Bgk-Type Kinetic Equations, Steven M. Wise, Evan Habbershaw

*Faculty Publications and Other Works -- Mathematics*

In this second progress report we expand upon our previous report and preliminary work. Specifically, we review some work on the numerical solution of single- and multi-species BGK-type kinetic equations of particle transport. Such equations model the motion of fluid particles via a density field when the kinetic theory of rarefied gases must be used in place of the continuum limit Navier-Stokes and Euler equations. The BGK-type equations describe the fluid in terms of phase space variables, and, in three space dimensions, require 6 independent phase-space variables (3 for space and 3 for velocity) for each species for accurate simulation. …

Numerical Study Of Owls' Leading-Edge Serrations, 2023 Coastal Carolina University

#### Numerical Study Of Owls' Leading-Edge Serrations, Asif Shahriar Nafi, Nikolaos Beratlis, Elias Balaras, Roi Gurka

*Physics and Engineering Science*

Owls' silent flight is commonly attributed to their special wing morphology combined with wingbeat kinematics. One of these special morphological features is known as the leading-edge serrations: rigid miniature hook-like patterns found at the primaries of the wings' leading-edge. It has been hypothesized that leading-edge serrations function as a passive flow control mechanism, impacting the aerodynamic performance. To elucidate the flow physics associated with owls' leading-edge serrations, we investigate the flow-field characteristic around a barn owl wing with serrated leading-edge geometry positioned at 20° angle of attack for a Reynolds number of 40 000. We use direct numerical simulations, where …

Combined Risk Based Inspection And Fault Tree Analysis For Repetitive 3-Phase Line Piping Leakage At West Java Offshore Topside Facility, 2023 Universitas Indonesia

#### Combined Risk Based Inspection And Fault Tree Analysis For Repetitive 3-Phase Line Piping Leakage At West Java Offshore Topside Facility, Dona Yuliati, Akhmad Herman Yuwono, Datu Rizal Asral, Donanta Dhaneswara

*Journal of Materials Exploration and Findings (JMEF)*

Hydrocarbon releases might result in serious consequences in various aspects. In addition to the contribution to environmental pollution, repetitive leakages need high repair costs. This study aim is to minimize potential repetitive leakage for other typical 3-phase piping systems. We conducted the risk assessment by adopting Risk Based Inspection (RBI) API 581 to identify risk level, calculating piping lifetime, recommended inspection plan and mitigations. The most relevant root causes can be obtained through quantitative Fault Tree Analysis (FTA). Observation and investigation was taken from eight 3-phase piping systems that experienced repetitive leakages. It has been found that the risk level …

Nitrogen Gas Quenching Pressure Effect On Bs S155 Alloy Steel In Vacuum Furnace, 2023 University of Indonesia, Depok

#### Nitrogen Gas Quenching Pressure Effect On Bs S155 Alloy Steel In Vacuum Furnace, Agus Mulyadi Hasanudin, Eddy Sumarno Siradj

*Journal of Materials Exploration and Findings (JMEF)*

The production of metal and alloy products requires the use of heat treatment, when during the heat treatment process, quenching is a crucial step. The quenching medium can be anything from water, a salt bath, oil, air and gas. In a vacuum furnace, pressurized gas, most frequently nitrogen (N_{2}) gas, serves as one of the quenching mediums. One of the drawbacks of the quenching process is the distortion and dimensional change of the parts. This paper aims to investigate the influence of nitrogen gas quenching pressure on the distortion and dimensional change of aerospace actuator gear planet parts …

Computational Fluid Dynamics Modeling Of Internal Wave Interactions On Conch Reef, Florida Keys, 2023 Nova Southeastern University

#### Computational Fluid Dynamics Modeling Of Internal Wave Interactions On Conch Reef, Florida Keys, Megan Miller

*All HCAS Student Capstones, Theses, and Dissertations*

Internal waves breaking on continental shelves play a significant role in mixing and nutrient delivery to coral reef ecosystems. As internal solitary waves, or solitons, propagate shoreward onto continental slopes, they can become unstable and break into turbulent bores that bring cool, nutrient-rich sub-thermocline water shoreward onto coral reefs. The propagation of turbulent bores generated by internal waves interacting with a complex surface creates high-frequency variabilities in the thermal and nutrient environment of Conch Reef in the Florida Keys, which has been studied previously. Here, I have created a three-dimensional model using ANSYS Fluent Computational Fluid Dynamics (CFD) software to …

Investigating The Effects Of A Southward Flow In The Southeastern Florida Shelf Using Robotic Instruments, 2023 Nova Southeastern University

#### Investigating The Effects Of A Southward Flow In The Southeastern Florida Shelf Using Robotic Instruments, Alfredo Quezada

*All HCAS Student Capstones, Theses, and Dissertations*

We deployed a Slocum G3 glider fitted with an acoustic Doppler current profiler (ADCP), a Conductivity-Temperature-Depth sensor (CTD), optics sensor channels, and a propeller on the Southeastern Florida shelf. The ADCP and CTD provide continuous measurements of Northern and Eastern current velocity components, salinity, temperature, and density, throughout the water column in a high-current environment. The optics sensor channels are able to provide measurements of chlorophyll concentrations, colored dissolved organic matter (CDOM), and backscatter particle counts. Additionally, for one of the glider deployments, we deployed a Wirewalker wave-powered profiling platform system also fitted with an ADCP and a CTD in …

Interactive Water Vortex Exhibit, 2023 California Polytechnic State University, San Luis Obispo

#### Interactive Water Vortex Exhibit, Simon Way, Emily Laing, Roqaya Naseri, Makenzie Kan

*Mechanical Engineering*

The San Luis Obispo Children’s Museum requested an interactive water vortex exhibit to both engage and entertain inquisitive guests, ages two to eight. The goal was to design and manufacture an exhibit that would educate its users on the fluid mechanics behind water vortices. They activate the mechanics by spinning a wheel, which is perceived as the catalyst to manipulate the flow of water to successfully create a whirlpool. Our team has created an interactive display that will enlighten young minds, providing the museum with an educational exhibit which shares a concept not currently taught by any other. Our project …

Wavelet Compression As An Observational Operator In Data Assimilation Systems For Sea Surface Temperature, 2023 University of New Orleans, New Orleans

#### Wavelet Compression As An Observational Operator In Data Assimilation Systems For Sea Surface Temperature, Bradley J. Sciacca

*University of New Orleans Theses and Dissertations*

The ocean remains severely under-observed, in part due to its sheer size. Containing nearly billion of water with most of the subsurface being invisible because water is extremely difficult to penetrate using electromagnetic radiation, as is typically used by satellite measuring instruments. For this reason, most observations of the ocean have very low spatial-temporal coverage to get a broad capture of the ocean’s features. However, recent “dense but patchy” data have increased the availability of high-resolution – low spatial coverage observations. These novel data sets have motivated research into multi-scale data assimilation methods. Here, we demonstrate a new assimilation approach …

Controlled Manipulation And Transport By Microswimmers In Stokes Flows, 2023 Clemson University

#### Controlled Manipulation And Transport By Microswimmers In Stokes Flows, Jake Buzhardt

*All Dissertations*

Remotely actuated microscale swimming robots have the potential to revolutionize many aspects of biomedicine. However, for the longterm goals of this field of research to be achievable, it is necessary to develop modelling, simulation, and control strategies which effectively and efficiently account for not only the motion of individual swimmers, but also the complex interactions of such swimmers with their environment including other nearby swimmers, boundaries, other cargo and passive particles, and the fluid medium itself. The aim of this thesis is to study these problems in simulation from the perspective of controls and dynamical systems, with a particular focus …

Microscale To Mesoscale Modeling Of The Ocean Under Tropical Cyclones: Effects Of Sea Spray And Surfactants On Tropical Cyclone Intensity And Air-Sea Gas Exchange, 2023 Nova Southeastern University

#### Microscale To Mesoscale Modeling Of The Ocean Under Tropical Cyclones: Effects Of Sea Spray And Surfactants On Tropical Cyclone Intensity And Air-Sea Gas Exchange, Breanna Lynn Cain Vanderplow

*All HCAS Student Capstones, Theses, and Dissertations*

Tropical cyclone intensity prediction remains a challenge despite computational and observational developments because successful intensity forecasting requires implementing a multitude of atmospheric and oceanic processes. Hurricane Maria 2017 and Hurricane Dorian 2019 serve as prime examples of rapidly intensifying storms that devastated communities in the Caribbean. A lack of understanding and parameterization of crucial physics involved in tropical cyclone intensity in existing forecast models may have led to these and other forecasting errors.

Microscale physical processes at the air-sea interface are a major factor in intensification of tropical cyclones that are often unaccounted for in forecasting models since they are …

Patterned Heating Induced Propulsion, 2023 Western University

#### Patterned Heating Induced Propulsion, Saajid A. Aman

*Electronic Thesis and Dissertation Repository*

This study explores propulsion effects generated by patterned heating acting on smooth and corrugated surfaces. The model problem assumes that the upper plate moves freely, and the lower plate is stationary, equipped with grooves, and exposed to spatially distributed heating. Our findings identify two distinct propulsion effects: thermal streaming and thermal drift. Thermal streaming occurs when given sufficient heating intensity with net flow in the left or right direction characterized by a pitchfork bifurcation. The efficiency of this technique can be controlled using the wavelength of heating. Thermal drift represents a pattern interaction effect. Its strength depends on the relative …

Dynamics And Scaling Of Particle Streaks In High-Reynolds-Number Turbulent Boundary Layers, 2023 Utah State University

#### Dynamics And Scaling Of Particle Streaks In High-Reynolds-Number Turbulent Boundary Layers, Tim Berk, Filippo Coletti

*Mechanical and Aerospace Engineering Faculty Publications*

Inertial particles in wall-bounded turbulence are known to form streaks, but experimental evidence and predictive understanding of this phenomenon is lacking, especially in regimes relevant to atmospheric flows. We carry out wind tunnel measurements to investigate this process, characterizing the transport of microscopic particles suspended in turbulent boundary layers. The friction Reynolds number R*e*_{𝜏} = *O*(10^{4}) allows for significant scale separation and the emergence of large-scale motions, while the range of viscous Stokes number S*t*^{+} = 18–870 is relevant to the transport of dust and fine sand in the atmospheric surface layer. We …

Modeling Single And Multiple Pacemaker Interaction In Jellyfish Locomotion, 2023 Illinois State University

#### Modeling Single And Multiple Pacemaker Interaction In Jellyfish Locomotion, Alexander Hoover

*Annual Symposium on Biomathematics and Ecology Education and Research*

No abstract provided.

Faster, Cheaper, And Better Cfd: A Case For Machine Learning To Augment Reynolds-Averaged Navier-Stokes, 2023 Old Dominion University

#### Faster, Cheaper, And Better Cfd: A Case For Machine Learning To Augment Reynolds-Averaged Navier-Stokes, John Peter Romano Ii

*Mechanical & Aerospace Engineering Theses & Dissertations*

In recent years, the field of machine learning (ML) has made significant advances, particularly through applying deep learning (DL) algorithms and artificial intelligence (AI). The literature shows several ways that ML may enhance the power of computational fluid dynamics (CFD) to improve its solution accuracy, reduce the needed computational resources and reduce overall simulation cost. ML techniques have also expanded the understanding of underlying flow physics and improved data capture from experimental fluid dynamics.

This dissertation presents an in-depth literature review and discusses ways the field of fluid dynamics has leveraged ML modeling to date. The author selects and describes …

The Role Of Nanofluids In Renewable Energy Engineering, 2023 Shandong University of Science and Technology

#### The Role Of Nanofluids In Renewable Energy Engineering, M. M. Bhatti, K. Vafai, Sara I. Abdelsalam

*Basic Science Engineering*

No abstract provided.

Interplay Of Forces In Impinging Jet Flow And Circular Hydraulic Jump, 2023 Western University

#### Interplay Of Forces In Impinging Jet Flow And Circular Hydraulic Jump, Abdelkader Baayoun

*Electronic Thesis and Dissertation Repository*

The circular liquid jet impingement with subsequent hydraulic jump formation is studied theoretically using boundary-layer and thin-film approaches. Three different scenarios are tackled, namely, an accelerated Newtonian jet impinging on a stationary disk, a steady Newtonian jet impinging on a rotating disk, and a steady viscoelastic liquid jet impinging on a stationary disk. Accordingly, the effects of jet acceleration, gravity, centrifugal forces, and fluid elasticity on the flow behaviour and the jump are examined. The results are validated against numerical simulation and existing measurements. The findings show that the thickness of the boundary layer developing near impingement diminishes with jet …

Bacterial Motion And Spread In Porous Environments, 2023 New Jersey Institute of Technology

#### Bacterial Motion And Spread In Porous Environments, Yasser Almoteri

*Dissertations*

Micro-swimmers are ubiquitous in nature from soil and water to mammalian bodies and even many technological processes. Common known examples are microbes such as bacteria, micro-algae and micro-plankton, cells such as spermatozoa and organisms such as nematodes. These swimmers live and have evolved in multiplex environments and complex flows in the presence of other swimmers and types, inert particles and fibers, interfaces and non-trivial confinements and more. Understanding the locomotion and interactions of these individual micro-swimmers in such impure viscous fluids is crucial to understanding the emergent dynamics of such complex systems, and to further enabling us to control and …

Fluid Dynamics Of Interacting Particles: Bouncing Droplets And Colloid-Polymer Mixtures, 2023 New Jersey Institute of Technology

#### Fluid Dynamics Of Interacting Particles: Bouncing Droplets And Colloid-Polymer Mixtures, Lauren Barnes

*Dissertations*

Interacting particles are a common theme across various physical systems, particularly on the atomic and sub-atomic scales. While these particles cannot be seen with the human eye, insight into such systems can be gained by observing macroscopic systems whose physical behavior is similar. This dissertation consists of three different chapters, each presenting a different problem related to interacting particles, as follows:

Chapter 1 explores chaotic trajectories of a droplet bouncing on the surface of a vertically vibrating fluid bath, with a simple harmonic force acting on the droplet. The bouncing droplet system has attracted recent interest because it exhibits behaviors …

Boundary Integral Equation Methods For Superhydrophobic Flow And Integrated Photonics, 2023 New Jersey Institute of Technology

#### Boundary Integral Equation Methods For Superhydrophobic Flow And Integrated Photonics, Kosuke Sugita

*Dissertations*

This dissertation presents fast integral equation methods (FIEMs) for solving two important problems encountered in practical engineering applications.

The first problem involves the mixed boundary value problem in two-dimensional Stokes flow, which appears commonly in computational fluid mechanics. This problem is particularly relevant to the design of microfluidic devices, especially those involving superhydrophobic (SH) flows over surfaces made of composite solid materials with alternating solid portions, grooves, or air pockets, leading to enhanced slip.

The second problem addresses waveguide devices in two dimensions, governed by the Helmholtz equation with Dirichlet conditions imposed on the boundary. This problem serves as a …

Variable Resolution Smoothed Particle Hydrodynamics Schemes For 2-D And 3-D Viscous Flows, 2023 New Jersey Institute of Technology

#### Variable Resolution Smoothed Particle Hydrodynamics Schemes For 2-D And 3-D Viscous Flows, Francesco Ricci

*Dissertations*

Smoothed Particle Hydrodynamics (SPH) is a Lagrangian particle-based method for the numerical solution of the partial differential equations that govern the motion of fluids. The main aim of this thesis work is to better enable the applicability of SPH to problems involving multi-scale fluid dynamics. In the first part of the thesis, the capability of the SPH method to simulate three-dimensional isotropic turbulence is investigated with a detailed comparison of Lagrangian and Eulerian SPH formulations. The main reason for this first investigation is to provide an assessment of the error introduced by the particle disorder on the SPH discrete operators …