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Articles 1 - 16 of 16

Full-Text Articles in Computational Engineering

Fedsm 2018 Presentation, Nima Fathi, Peter Vorobieff, Seyed Sobhan Aleyasin, Goodarz Ahmadi Jul 2018

Fedsm 2018 Presentation, Nima Fathi, Peter Vorobieff, Seyed Sobhan Aleyasin, Goodarz Ahmadi

Nima Fathi

Horizontal linear shear stress apparatus offers a convenient way to study the rheology of rigid particles suspended in viscous shear flows in the laboratory. The single particle trajectories of a buoyant spherical solid particle in a linear shear flow are investigated. Reynolds numbers less than 0.1 are considered to provide the creeping flow in this investigating. The experimental apparatus provides a linear stress, Stokes, Couette flow where the wall boundary conditions of the set up can change. The two-dimensional CFD analysis is performed to simulate the primary and secondary phases of the domain. Our numerical assessment, discrete phase element ...


Multiphase Flow Modeling For Design And Optimization Of A Novel Down-Flow Bubble Column, Mutharasu Lalitha Chockalingam Dec 2017

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 Nov 2017

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 ...


Multiscale Wind Modelling For Sustainability And Resilience, Djordje Romanic Oct 2016

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 ...


Testing The Accuracy Of Commercial Computational Fluid Dynamics Codes: Vortex Transport By Uniform Flow And Transonic Ringleb Flow Problems Using Ansys Fluent, Carl Leake Aug 2016

Testing The Accuracy Of Commercial Computational Fluid Dynamics Codes: Vortex Transport By Uniform Flow And Transonic Ringleb Flow Problems Using Ansys Fluent, Carl Leake

College of Engineering

This study juxtaposes the accuracy of a commercial computational fluid dynamics (CFD) software, ANSYS Fluent, against two CFD research codes, EZ4D and Flux Reconstruction. The study uses three problems to make the comparison, two vortex transport problems and one Ringleb flow problem. Fluent was used to simulate all problems, however, data sets from each CFD research code were not available for all cases. The first vortex problem showed that quadrilateral meshes perform better in Fluent than triangular meshes when the flow is aligned normal to quadrilateral cells. In addition, it revealed that Fluent has more dissipation error but less phase ...


Modified Numerical-Analytical Analysis On Scpps, Nima Fathi, Seyed Sobhan Aleyasin, Peter Vorobieff Mar 2016

Modified Numerical-Analytical Analysis On Scpps, Nima Fathi, Seyed Sobhan Aleyasin, Peter Vorobieff

Nima Fathi

In this study an appropriate expression to estimate the output power of solar chimney power plant systems (SCPPS) was considered. Recently several mathematical models of SCPPS were derived, studied for a variety of boundary conditions, and compared against CFD calculations. An important concern for modeling SCPPS is the accuracy of the derived pressure drop and output power equation. To elucidate the matter, axisymmetric CFD analysis was performed to model the solar chimney power plant and calculate the output power for different available solar radiation. Both analytical and numerical results were compared against the available experimental data from the historical Manzanares ...


Project Oasis: Optimizing Aquaponic Systems To Improve Sustainability, Siddharth Nigam, Paige Balcom Jan 2016

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 ...


Eulerian Cfd Modeling Of Multiphase Internal Injector Flow And External Sprays, Eli T. Baldwin Jan 2016

Eulerian Cfd Modeling Of Multiphase Internal Injector Flow And External Sprays, Eli T. Baldwin

Doctoral Dissertations

The improvement of combustion systems which use sprays to atomize liquid fuel requires an understanding of that atomization process. Although the secondary break up mechanisms for the far-field of an atomizing spray have been thoroughly studied and well understood for some time, understanding the internal nozzle flow and primary atomization on which the far-field spray depends has proven to be more of a challenge. Flow through fuel injector nozzles can be highly complex and heavily influenced by factors such as turbulence, needle motion, nozzle imperfections, nozzle asymmetry, and phase change. All of this occurs within metallic injectors, making experimental characterization ...


Optimization Of Blalock-Taussig Shunt And Anastomotic Geometry For Vascular Access Fistula Using A Genetic Algorithm, Guangyu Bao Aug 2015

Optimization Of Blalock-Taussig Shunt And Anastomotic Geometry For Vascular Access Fistula Using A Genetic Algorithm, Guangyu Bao

Engineering and Applied Science 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 Dec 2013

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 ...


Essentially Analytical Theory Closure For Space Filtered Thermal-Incompressible Navier-Stokes Partial Differential Equation System On Bounded Domains, Mikhail Alexandrovich Sekachev Aug 2013

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 Dec 2012

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 described ...


Development And Verification Of A Navier-Stokes Solver With Vorticity Confinement Using Openfoam, Austin Barrett Kimbrell May 2012

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 Jun 2011

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 Apr 2010

High Order Finite Elements For Lagrangian Computational Fluid Dynamics, Truman Everett Ellis

Master's Theses and Project Reports

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 Apr 2009

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 ...