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Articles 1 - 22 of 22
Full-Text Articles in Engineering
Development Of On-The-Fly Quasi-Steady State Approximation For Chemical Kinetics In Cfd, Abhinav Balamurugan
Development Of On-The-Fly Quasi-Steady State Approximation For Chemical Kinetics In Cfd, Abhinav Balamurugan
Doctoral Dissertations and Master's Theses
This study analyzes the feasibility of On-The-Fly Quasi-Steady-State Approximation (OTF-QSSA) application for solving chemical kinetics within Computational Fluid Dynamics (CFD) simulations, aiming to reduce the computational demand of detailed mechanisms. An algorithm that dynamically identifies and designates Quasi-Steady-State (QSS) species at specific grid locations and instances during the simulation was developed. With this information, our method pseudo-delays the advancement of concentrations for these QSS species—effectively setting their rate of concentration change to zero for a set number iteration before updating using the detailed mechanism and thereby omitting the computationally intensive processes typically required for their calculation during those skipped iteration. …
Computational Study Of Dense Gas Dispersion In Urban Areas, Rasna Sharmin
Computational Study Of Dense Gas Dispersion In Urban Areas, Rasna Sharmin
All Dissertations
A series of steady-state simulations have been conducted to investigate removal of dense gas from a simple square canyon formed between two square cross-section obstacles. Due to urbanization and industrialization, there always lies a high risk of exposure to harmful pollutants which can result from accidental release of toxic gasses. Those are often denser than the atmosphere. and can easily get trapped in between buildings in urban canopies. It is important to have full understanding of flushing mechanism of dense fluid inside urban canopies by steady turbulent flow because the exposure to these toxic dense gasses can be catastrophic. There …
Ternary Flow Simulation Based On The Conservative Phase Field Lattice Boltzmann Method, Chunheng Zhao
Ternary Flow Simulation Based On The Conservative Phase Field Lattice Boltzmann Method, Chunheng Zhao
Dissertations and Theses
In this thesis, we numerically investigated multi-phase fluid dynamics (2 and 3-phase flow) by solving the Navier-Stokes equations coupled with the conservative phase field (CPF) equations using the Lattice Boltzmann method (LBM). To effectively simulate the large-scale multi-phase physics, we developed an open-source software, IMEXLBM, which can be easily parallelized on both CPUs and GPUs without significant modifications to the code. We first validated various parts of this software and then used this method to study the interaction of rising bubbles with a static oil droplet as well as the engulfment of the water droplet on solids coated with a …
A Cfd Study Of Steady Fully Developed Laminar Flow Through A 90-Degree Bend Pipe With A Square Cross-Sectional Area, Subodh Sushant Toraskar
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. …
Toward A Fast And Accurate Modeling Strategy For Thermal Management In Air-Cooled Data Centers, Long Tran Bao Phan
Toward A Fast And Accurate Modeling Strategy For Thermal Management In Air-Cooled Data Centers, Long Tran Bao Phan
FIU Electronic Theses and Dissertations
Computational fluid dynamics (CFD) has become a popular tool compared to experimental measurement for thermal management in data centers. However, it is very time-consuming and resource-intensive when used to model large-scale data centers, and may not be ready for real-time thermal monitoring. In this thesis, the two main goals are first to develop rapid flow simulation to reduce the computing time while maintaining good accuracy, and second, to develop a whole building energy simulation (BES) strategy for data center modeling. To achieve this end, hybrid modeling and model training methodologies are investigated for rapid flow simulation, and a multi-zone model …
Transient Flow Analysis Of A Closing Blowout Preventer Using Computational Fluid Dynamics (Cfd), Daniel Barreca
Transient Flow Analysis Of A Closing Blowout Preventer Using Computational Fluid Dynamics (Cfd), Daniel Barreca
LSU Master's Theses
Reliability of blowout preventers (BOPs) is crucial for drilling and production operations. Erosion of BOP components and hydrodynamic forces on rams may cause failure of BOP elements to seal the well. Transient computational fluid dynamics (CFD) simulations of fluids within the wellbore and BOP offer quantitative and qualitative data related to this reliability during the closure of various BOP components. Since limited research has been published in transient CFD simulations of closing BOPs, this thesis discusses challenges and solutions to simulating closing blowout preventers. Single component fluids are simulated through several BOP geometries such as annular preventers, pipe rams, and …
Fluid Agitation Studies For Drug Product Containers Using Computational Fluid Dynamics, Matthew Hiroki Ichinose
Fluid Agitation Studies For Drug Product Containers Using Computational Fluid Dynamics, Matthew Hiroki Ichinose
Master's Theses
At Amgen, the Automated Vision Inspection (AVI) systems capture the movement of unwanted particles in Amgen's drug product containers. For quality inspection, the AVI system must detect these undesired particles using a high speed spin-stop agitation process. To better understand the fluid movements to swirl the particles away from the walls, Computational Fluid Dynamics (CFD) is used to analyze the nature of the two phase flow of air and a liquid solution.
Several 2-D and 3-D models were developed using Fluent to create simulations of Amgen's drug product containers for a 1 mL syringe, 2.25 mL syringe, and a 5 …
Fedsm 2018 Presentation, Nima Fathi, Peter Vorobieff, Seyed Sobhan Aleyasin, Goodarz Ahmadi
Fedsm 2018 Presentation, Nima Fathi, Peter Vorobieff, Seyed Sobhan Aleyasin, Goodarz Ahmadi
Nima Fathi
Multiphase Flow Modeling For Design And Optimization Of A Novel Down-Flow Bubble Column, Mutharasu Lalitha Chockalingam
Multiphase Flow Modeling For Design And Optimization Of A Novel Down-Flow Bubble Column, Mutharasu Lalitha Chockalingam
LSU Doctoral Dissertations
The application of the Euler-Euler framework based Computational Fluid Dynamics (CFD) models for simulating the two-phase gas-liquid bubbly flow in down-flow bubble columns is discussed in detail. Emphasis is given towards the modelling and design optimization of a novel down-flow bubble column. The design features of this novel down-flow bubble column and its advantages over a conventional Plunging Jet down-flow bubble column are discussed briefly. Then, some of the present challenges in simulating a conventional Plunging Jet down-flow bubble column in the Euler-Euler framework is highlighted, and a sigmoid function based drag modification function is implemented to overcome those challenges. …
A High Quality, Eulerian 3d Fluid Solver In C++, Lejon Anthony Mcgowan
A High Quality, Eulerian 3d Fluid Solver In C++, Lejon Anthony Mcgowan
Computer Science and Software Engineering
Fluids are a part of everyday life, yet are one of the hardest elements to properly render in computer graphics. Water is the most obvious entity when thinking of what a fluid simulation can achieve (and it is indeed the focus of this project), but many other aspects of nature, like fog, clouds, and particle effects. Real-time graphics like video games employ many heuristics to approximate these effects, but large-scale renderers aim to simulate these effects as closely as possible.
In this project, I wish to achieve effects of the latter nature. Using the Eulerian technique of discrete grids, I …
Computational Fluid Dynamics Is Key To Better Flying Aircraft, Nihad E. Daidzic
Computational Fluid Dynamics Is Key To Better Flying Aircraft, Nihad E. Daidzic
Aviation Department Publications
No abstract provided.
Multiscale Wind Modelling For Sustainability And Resilience, Djordje Romanic
Multiscale Wind Modelling For Sustainability And Resilience, Djordje Romanic
Electronic Thesis and Dissertation Repository
The research presented herein is a mix of meteorological and wind engineering disciplines. In many cases, there is a gap between these two fields and this thesis is an attempt to bridge that gap through multiscale wind modelling approaches. Data and methods used in this study cover a multitude of spatial and temporal scales. Applications are in the fields of sustainability and resilience. This relationship between multiscale wind modelling and sustainability and resilience is investigated examining several case studies of three different developments: urban, rural and coastal.
An urban wind modelling methodology is proposed and applied for a specific development …
Modified Numerical-Analytical Analysis On Scpps, Nima Fathi, Seyed Sobhan Aleyasin, Peter Vorobieff
Modified Numerical-Analytical Analysis On Scpps, Nima Fathi, Seyed Sobhan Aleyasin, Peter Vorobieff
Nima Fathi
Project Oasis: Optimizing Aquaponic Systems To Improve Sustainability, Siddharth Nigam, Paige Balcom
Project Oasis: Optimizing Aquaponic Systems To Improve Sustainability, Siddharth Nigam, Paige Balcom
Honors Theses and Capstones
Started in Fall 2015, Project OASIS (Optimizing Aquaponic Systems to Improve Sustainability) is an interdisciplinary capstone project with the goal of designing a sustainable and affordable small-scale aquaponic system for use in developing nations to tackle the problems of malnutrition and food insecurity. Aquaponics is a symbiotic relationship between fish and vegetables growing together in a recirculating system. The project’s goals were to minimize energy consumption and construction costs while using universally available materials. The computational fluid dynamics (CFD) software OpenFOAM was used to create transient and steady-state models of fish tanks to visualize velocity profiles, streamlines, and particle movement. …
Optimization Of Blalock-Taussig Shunt And Anastomotic Geometry For Vascular Access Fistula Using A Genetic Algorithm, Guangyu Bao
Optimization Of Blalock-Taussig Shunt And Anastomotic Geometry For Vascular Access Fistula Using A Genetic Algorithm, Guangyu Bao
McKelvey School of Engineering Theses & Dissertations
Blalock-Taussig (BT) shunts are used for defects that affect the flow of blood from the right ventricle, through the pulmonary artery, and to the lungs. Arteriovenous (AV) fistula is one type of vascular access which is a surgically created vein used to remove and return blood during hemodialysis. Plastic grafts used in the above two reconstructions may result in areas of non-physiologic flow in the grafts leading to risk of stenosis (blocked area) and thrombosis, which is the single major cause for access morbidity. The focus of this thesis is to study BT shunts and anastomoses models using Computational Fluid …
Numerical Modelling Of Downburst Interaction With Bluff Body, Aditi Jog
Numerical Modelling Of Downburst Interaction With Bluff Body, Aditi Jog
Electronic Thesis and Dissertation Repository
The objective of this study is to investigate the interaction of a bluff body with a downburst flow. Numerical investigation of the flow field using CFD analysis was carried out for three different downburst sizes (h/d=1, 2, 4) under suitable boundary conditions subjected to constant jet velocity. The downburst-structure interaction study was conducted for two jet diameters (h/d=1 and 4) and two radial locations from the downburst center.
The results showed that the downburst size greatly dominates the intensity of the flow. The largest downburst resulted in the highest velocity magnitude near the ground and also covered a larger area …
Essentially Analytical Theory Closure For Space Filtered Thermal-Incompressible Navier-Stokes Partial Differential Equation System On Bounded Domains, Mikhail Alexandrovich Sekachev
Essentially Analytical Theory Closure For Space Filtered Thermal-Incompressible Navier-Stokes Partial Differential Equation System On Bounded Domains, Mikhail Alexandrovich Sekachev
Doctoral Dissertations
Numerical simulation of turbulent flows is identified as one of the grand challenges in high-performance computing. The straight forward approach of solving the Navier-Stokes (NS) equations is termed Direct Numerical Simulation (DNS). In DNS the majority of computational effort is spent on resolving the smallest scales of turbulence, which makes this approach impractical for most industrial applications even on present-day supercomputers. A more feasible approach termed Large Eddy Simulation (LES) has evolved over the last five decades to facilitate turbulent flow predictions for reasonable Reynolds (Re) numbers and domain sizes. LES theory uses the concept of convolution with a spatial …
Modelling Three-Phase Flow In Metallurgical Processes, Christoph Goniva, Gijsbert Wierink, Kari Heiskanen, Stefan Pirker, Christoph Kloss
Modelling Three-Phase Flow In Metallurgical Processes, Christoph Goniva, Gijsbert Wierink, Kari Heiskanen, Stefan Pirker, Christoph Kloss
Gijsbert Wierink
The interaction between gasses, liquids, and solids plays a critical role in many processes, such as coating, granulation and the blast furnace process. In this paper we present a comprehensive numerical model for three phase flow including droplets, particles and gas. By means of a coupled Computational Fluid Dynamics (CFD) - Discrete Element Method (DEM) approach the physical core phenomena are pictured at a detailed level. Sub-models for droplet deformation, breakup and coalescence as well as droplet-particle and wet particle-particle interaction are applied. The feasibility of this model approach is demonstrated by its application to a rotating drum coater. The …
Development And Verification Of A Navier-Stokes Solver With Vorticity Confinement Using Openfoam, Austin Barrett Kimbrell
Development And Verification Of A Navier-Stokes Solver With Vorticity Confinement Using Openfoam, Austin Barrett Kimbrell
Masters Theses
Vorticity Confinement (VC) is a numerical technique which enhances computation of fluid flows by acting as negative diffusion within the limit of vortical regions, preventing the inherent numerical dissipation present with conventional methods. VC shares similarities with large eddy simulation (LES), but its behavior is based on a stable negative dissipation of vortical structures controlled by the automatic balance between two parameters, μ [mu] and ε [epsilon].
In this thesis, three-dimensional, parallel-computing Navier-Stokes solvers with VC are developed using the OpenFOAM computational framework. OpenFOAM is an open-source collection of C++ libraries developed for computational fluid dynamics. Object-oriented programming concepts are …
Cavitation Modelling Based On Eulerian-Eulerian Multiphase Flow, Rachid Bannari Ph.D
Cavitation Modelling Based On Eulerian-Eulerian Multiphase Flow, Rachid Bannari Ph.D
Rachid BANNARI
Cavitation is a physical phenomenon encountered in the normal operation of hydraulic turbines. It can lead to loss in efficiency, vibrations and blade erosion damages. It is crucial to accurately predict cavitation development and evolution to make confident predictive results for hydraulic turbines in a cavitating regime. The cavity closure is a critical region that is characterized by its unsteady and unstable behavior. In this region, liquid and vapor are highly mixed and experienced a strong interaction between the cavity and the outer flow. Most of the published work is based on the mixture multiphase model. An important limitation of …
High Order Finite Elements For Lagrangian Computational Fluid Dynamics, Truman Everett Ellis
High Order Finite Elements For Lagrangian Computational Fluid Dynamics, Truman Everett Ellis
Master's Theses
A general finite element method is presented to solve the Euler equations in a Lagrangian reference frame. This FEM framework allows for separate arbitrarily high order representation of kinematic and thermodynamic variables. An accompanying hydrodynamics code written in Matlab is presented as a test-bed to experiment with various basis function choices. A wide range of basis function pairs are postulated and a few choices are developed further, including the bi-quadratic Q2-Q1d and Q2-Q2d elements. These are compared with a corresponding pair of low order bi-linear elements, traditional Q1-Q0 and sub-zonal pressure Q1-Q1d. Several test problems are considered including static convergence …
A Coupled Cfd-Kinetic Models For Cellulase Production In Airlift Reactor, Rachid Bannari, Abdelfettah Bannari, Brahim Selma, Pierre Proulx
A Coupled Cfd-Kinetic Models For Cellulase Production In Airlift Reactor, Rachid Bannari, Abdelfettah Bannari, Brahim Selma, Pierre Proulx
Rachid BANNARI
Cellulase production provides a catalyst for cellulose hydrolysis to glucose, to be used for eventual production of ethanol. The transport of reactants may influence the reaction rate remarkably, for the biological reaction, especially the enzymatic reaction, The transport behavior of the components in a biological system should be considered in the model. In this work, we propose a coupled model between hydrodynamics (twoPhaseEuler- Foam) and a kinetic model for batch and fed-batch cellulase enzyme production by T. reesei from cellulose/lactose substrate which is constructed from literature concepts and laboratory data. Good agreement is obtained between the results and experimental data.