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2019

CFD

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Full-Text Articles in Engineering

Unsupervised-Learning Assisted Artificial Neural Network For Optimization, Varun Kote Jul 2019

Unsupervised-Learning Assisted Artificial Neural Network For Optimization, Varun Kote

Mechanical & Aerospace Engineering Theses & Dissertations

Innovations in computer technology made way for Computational Fluid Dynamics (CFD) into engineering, which supported the development of new designs by reducing the cost and time by lowering the dependency on experimentation. There is a further need to make the process of development more efficient. One such technology is Artificial Intelligence. In this thesis, we explore the application of Artificial Intelligence (AI) in CFD and how it can improve the process of development.

AI is used as a buzz word for the mechanism which can learn by itself and make the decision accordingly. Machine learning (ML) is a subset of ...


Optimization Of Window Confirguration In Buildings For Sustainable Thermal And Lighting Performance, Meseret Tesfay Kahsay May 2019

Optimization Of Window Confirguration In Buildings For Sustainable Thermal And Lighting Performance, Meseret Tesfay Kahsay

Electronic Thesis and Dissertation Repository

In recent years, there is an urban architectural evolution towards significant use of glazing in high-rise buildings. Windows play a critical role in moderating the elements of the climate. Although good for outdoor viewing and daylighting, glazing has very little ability to control heat flow and solar heat gain. As a result, about 20 - 40% of the energy in a building is wasted through windows. Finding an optimal configuration of windows is a complex task due to its conflicting objectives, such as outdoor view, daylighting, and thermal comfort demands. Further buildings interact with the microclimate in a complex manner, the ...


Numerical Investigation Of Coalescence-Induced Self-Propelled Behavior Of Droplets On Non-Wetting Surfaces And Wedged Surfaces., Yan Chen May 2019

Numerical Investigation Of Coalescence-Induced Self-Propelled Behavior Of Droplets On Non-Wetting Surfaces And Wedged Surfaces., Yan Chen

Electronic Theses and Dissertations

When small drops coalesce on a superhydrophobic surface, the merged drop can jump away from the surface due to the surface energy released during the coalescence. This self-propelled behavior has been observed on various superhydrophobic surfaces and has potential applications in areas related to the heat and mass transfer, such as heat exchangers, anti-icing and anti-frost devices, thermal management and water harvesting. The jumping velocity model was obtained based on published experimental data and the balance of various energy terms described in previous studies. However, the self-propelled mechanism is still not fully understood. In this study, the self-propelled droplet phenomenon ...


Cavitation Number As A Function Of Disk Cavitator Radius: A Numerical Analysis Of Natural Supercavitation, Reid Prichard Apr 2019

Cavitation Number As A Function Of Disk Cavitator Radius: A Numerical Analysis Of Natural Supercavitation, Reid Prichard

Senior Honors Theses

Due to the greater viscosity and density of water compared to air, the maximum speed of underwater travel is severely limited compared to other methods of transportation. However, a technology called supercavitation – which uses a disk-shaped cavitator to envelop a vehicle in a bubble of steam – promises to greatly decrease skin friction drag. While a large cavitator enables the occurrence of supercavitation at low velocities, it adds substantial unnecessary drag at higher speeds. Based on CFD results, a relationship between cavitator diameter and cavitation number is developed, and it is substituted into an existing equation relating drag coefficient to cavitation ...


Horizontal Flow Loop Design For The Study Of Drill String Rotation Effects On Cuttings Transport, David C. Rathgeber Apr 2019

Horizontal Flow Loop Design For The Study Of Drill String Rotation Effects On Cuttings Transport, David C. Rathgeber

Graduate Theses & Non-Theses

Exploration and Production companies are continually focusing more time, energy and resources into Extended Reach Drilling in order to maximize reservoir production while minimizing both environmental impact and development costs. These long laterals (2:1 Measured Depth: True Vertical Depth) are often more difficult to drill and can be severely impacted by inadequate drilling practices. Cuttings transport efficiency is a critical parameter of Extended Reach Drilling operations, and poor wellbore cleaning can lead to excessive torque, drag, and several other serious downhole problems.

Although many studies have been performed that identify the importance of drill string rotation on cuttings movement ...


The Characterization Of Char Particle Morphology And Its Effects On Combustion, Scott Jorgensen Apr 2019

The Characterization Of Char Particle Morphology And Its Effects On Combustion, Scott Jorgensen

Master's Theses (2009 -)

Char particle combustion typically occurs under internal diffusion control, which results in inter-particle reactant gradients. Reactant concentrations throughout the char’s carbon structure must be known in order to predict overall particle reaction rates. These concentrations can be predicted by analytical models; however, effects of char morphology are typically ignored within these simplified models. In order to incorporate these effects, the morphology of Illinois coal #6 was studied by visualizing their structure in three-dimensions through the use of micro-computed tomography. Morphological characteristics of macro-porosity, macro-porosity location, and wall thickness were then measured for the sampled char particles. The sampled char ...


Sweep And Taper Analysis Of Surfboard Fins Using Computational Fluid Dynamics, Brandon James Baldovin Mar 2019

Sweep And Taper Analysis Of Surfboard Fins Using Computational Fluid Dynamics, Brandon James Baldovin

Master's Theses and Project Reports

The research presented here provides a basis for understanding the hydrodynamics of surfboard fin geometries. While there have been select studies on fins there has been little correlation to the shape of the fin and its corresponding hydrodynamic performance. This research analyzes how changing the planform shape of a surfboard fin effects its performance and flow field. This was done by isolating the taper and sweep distribution of a baseline geometry and varying each parameter individually whilst maintaining a constant span and surface area. The baseline surfboard fin was used as a template in Matlab to generate a set of ...


A Higher-Order Method Implemented In An Unstructured Panel Code To Model Linearized Supersonic Flows, Jake Daniel Davis Feb 2019

A Higher-Order Method Implemented In An Unstructured Panel Code To Model Linearized Supersonic Flows, Jake Daniel Davis

Master's Theses and Project Reports

Since their conception in the 1960s, panel codes have remained a critical tool in the design and development of air vehicles. With continued advancement in computational technologies, today's codes are able to solve flow fields around arbitrary bodies more quickly and with higher fidelity than those that preceded them. Panel codes prove most useful during the conceptual design phase of an air vehicle, allowing engineers to iterate designs, and generate full solutions of the flow field around a vehicle in a matter of seconds to minutes instead of hours to days using traditional CFD methods. There have been relatively ...


Adding Semi-Structured Automated Grid Generation And The Menter-Shear Stress Turbulence Transport Model For Internal Combustion Engine Simulations To Novel Fem Lanl Combustion Codes, Brad Montgomery Philipbar Jan 2019

Adding Semi-Structured Automated Grid Generation And The Menter-Shear Stress Turbulence Transport Model For Internal Combustion Engine Simulations To Novel Fem Lanl Combustion Codes, Brad Montgomery Philipbar

Mechanical Engineering ETDs

The addition of GridPro semi-structured, automated generation of grids for complex moving boundaries for combustion engine applications and the Menter Shear Stress Turbulent Transfer (SST) model are being developed by Los Alamos National Laboratory. The software is called Fast, Easy, Accurate, and Robust Continuum Engineering (FEARCE). In addition to improving the time and effort required to build complex grid geometry for turbulent reactive multi-phase flow in internal combustion engines, the SST turbulence model has been programmed into the Predictor Corrector Fractional-Step (PCS) Finite Element Method (FEM) for reactive flow and turbulent incompressible flow regime validation is performed. The Reynolds-Averaged Navier-Stokes ...


Ignition And Extinction Behavior Of Fuels In A Microcombustor, Pawan Sharma Jan 2019

Ignition And Extinction Behavior Of Fuels In A Microcombustor, Pawan Sharma

LSU Doctoral Dissertations

Conventional fuel testing device-CFR engine requires large quantities of fuels, which makes it unsuitable for research of small samples of fuels. This current study seeks to address this limitation by using an externally heated microcombustor as an alternative fuel testing device. Mainly three combustion behaviors have been observed inside a microcombustor: strong flames at higher flow rates, Flames with Repetitive Extinction and Ignition (FREI) at intermediate flow rates, and weak flames at marginal flow rates. In previous studies, weak combustion behavior has been proven suitable to study fuel properties from small samples of fuels. Microcombustor experiments typically rely on flame ...


Magneto-Active Slosh Control System Using Free Floating Membrane For Cylinderical Propellant Tanks Read More: Https://Arc.Aiaa.Org/Doi/Abs/10.2514/6.2019-2177, Pedro Llanos Jan 2019

Magneto-Active Slosh Control System Using Free Floating Membrane For Cylinderical Propellant Tanks Read More: Https://Arc.Aiaa.Org/Doi/Abs/10.2514/6.2019-2177, Pedro Llanos

Pedro J. Llanos (www.AstronauticsLlanos.com)

The phenomenon of sloshing is a substantial challenge in propellant management, particularly in reduced gravity where surface tension-driven flows result in large slosh amplitudes and relatively long decay time scales. Propellant Management Devices (PMDs) such as the rigid baffles and elastomeric membranes are often employed to counteract motion of the free surface. In the present study, we investigate an active PMD that utilizes a free-floating membrane that, under an applied static magnetic field, becomes rigid and suppresses slosh. This semi-rigid structural layer can thereby replace bulky baffle structures and reduce the overall weight of the tank. In this paper, the ...


Computational Study Of Water Desalination Using Forward Osmosis, Ahmed Mohammed Alshwairekh Jan 2019

Computational Study Of Water Desalination Using Forward Osmosis, Ahmed Mohammed Alshwairekh

Theses and Dissertations

Forward Osmosis is a natural phenomenon that takes places across a semi-permeable membrane when there is a concentration difference across the membrane. Pure water permeates to the highly concentrated channel until the concentration across the membrane equilibrates. In water desalination applications, the same principle is applied. Spiral-wound membrane, flat sheet, or hollow fiber module are typical configurations in forward osmosis desalination modules. The application of water desalination using forward osmosis requires the existence of two channels separated by a suitable forward osmosis membrane. Sea or Brackish water is introduced in one side while the other side has a suitable draw ...


The Effects Of Low Aspect Ratio And Heat Exchanging Internals On The Bubble Properties And Flow Regime In A Pilot-Plant Bubble/Slurry Bubble Column For Fischer-Tropsch Synthesis, Hayder Al-Naseri Jan 2019

The Effects Of Low Aspect Ratio And Heat Exchanging Internals On The Bubble Properties And Flow Regime In A Pilot-Plant Bubble/Slurry Bubble Column For Fischer-Tropsch Synthesis, Hayder Al-Naseri

Doctoral Dissertations

"Fischer-Tropsch synthesis (F-T) is a process utilized to convert the syngas mixture of CO and H2 to synthetic fuel and chemicals that executed commercially by using the bubble/slurry bubble column reactor. The experimental results reveal that the investigated parameters, in terms the presence of internals, and reducing the aspect ratio and the solids loading, increase the local gas holdup, interfacial area, bubble passage frequency, and decrease the bubble rise velocity, bubble chord length. Meanwhile, the aspect ratio H/D = 4, and 5 provide enough height to established the fully developed flow regime. As a result of the variation ...


Computational Study Of Flow Interactions Over A Close Coupled Canard-Wing On Fighter, Setyawan Bekti Wibowo, Sutrisno Sutrisno, Tri Agung Rohmat Jan 2019

Computational Study Of Flow Interactions Over A Close Coupled Canard-Wing On Fighter, Setyawan Bekti Wibowo, Sutrisno Sutrisno, Tri Agung Rohmat

International Journal of Aviation, Aeronautics, and Aerospace

There have been many attempts to improve the flying performance of a fighter. By modifying the flow that occurs along the fuselage is expected to improve the performance of the aircraft. One of the indicators of combat aircraft performance is the ability to perform maneuver movement. Adding a canard as forewing on the fighter wing configuration is considered capable of raising the ability in maneuver movement. The use of canard-delta pairs will affect the performance and aerodynamic characteristics of the plane. Wings and canards with delta configuration will make the rolled-up vortex as a lifting force producer on the aircraft ...


Employing 2-D Cfd & Lrb Model Around Trees To Improve Vawt Placement, David Chukwuebuka Bassey Jan 2019

Employing 2-D Cfd & Lrb Model Around Trees To Improve Vawt Placement, David Chukwuebuka Bassey

All Theses, Dissertations, and Other Capstone Projects

In the placement of vertical axis wind turbines, trees are a constant presence in the vicinity. They are found to grow at different height and shape configurations. And in areas such as the Minnesota State University, Mankato (MNSU) campus, they serve as blockage to airflow; limiting the efficiency of installed turbines. This work sets the precedent for the validation of vegetative numerical models created for the Xcel Energy Research Development Fund (RDF) project.

Using two-dimensional (2-D) numerical simulations of porous cylinders placed in a rectangular medium of air, insight into the flow profile and distribution in the leeward side of ...