A numerical investigation of the interaction of a planar shock wave with a rigid wedge and cone in an air-filled shock tube is performed by computing the unsteady flow field of the interaction process. The Euler and Navier-Stokes equations are solved in two dimensions to produce flow solutions for regular and Mach reflections with and without the viscous and thermal boundary layer on the inclined surface. The transition boundary between these two patterns is determined by changing both the shock strength and the angle of the inclined surface so that the simulations are perpendicular to the theoretical transition boundary. The numerically determined boundaries are compared to the theoretical boundaries predicted by two- and three- shock theories and with results obtained from experiments. The results show that the transition boundary between regular and Mach reflection is different not only for wedges and cones but also for inviscid and viscous numerical solutions.

A numerical investigation of the interaction of a planar shock wave with a rigid wedge and cone in an air-filled shock tube is performed by computing the unsteady flow field of the interaction process. The Euler and Navier-Stokes equations are solved in two dimensions to produce flow solutions for regular and Mach reflections with and without the viscous and thermal boundary layer on the inclined surface. The transition boundary between these two patterns is determined by changing both the shock strength and the angle of the inclined surface so that the simulations are perpendicular to the theoretical transition boundary. The numerically determined boundaries are compared to the theoretical boundaries predicted by two- and three- shock theories and with results obtained from experiments. The results show that the transition boundary between regular and Mach reflection is different not only for wedges and cones but also for inviscid and viscous numerical solutions.

A numerical method is used to predict flow fields and forces for squeeze film dampers (SFDs). A two dimensional SFD is modeled with different amplitudes and frequencies of the journal orbiting inside the wall. In addition to the typical circular centered orbit (CCO) motion prescribed in most studies, orbits can vary greatly from circular to linear. The study is divided into two distinctive models including single phase flow model and two phase flow model. The single phase flow model cases including three amplitudes, i.e. 0.002, 0.001, and 0.0005 inches, and three frequencies, i.e. 10, 50, and 200 Hz, of journal motions are conducted to portray flow fields and forces and ultimately determine their relationships. The numerical prediction shows that the journal amplitude and frequency affect flow and consequently force in the SFD. The force is directly proportional to frequency and motion amplitude. Owing to the presence of cavitation in the practical SFD, the two phase flow model is also presented with the journal amplitude of 0.0002 and three frequencies of 10, 50, and 100 Hz, respectively. The ambient pressure condition was set up for numerical processing ranging from 0.001 Mpa to 100 Mpa. The results indicate that the operating pressure has an integral role in suppressing the presence of the cavitation. The caviation disappears if the operating pressure is high enough above the vapor pressure of the lubricant.

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Recirculating turbulent flow within a cavity with an inlet wall jet was examined. In steady water flow velocity profiles were constructed with measurements taken with a Laser Doppler Anemometer system mounted on a traversing mechanism. Two test cases were examined Re jet = 1167 and Re jet = 3231 as well as developing wall jet profiles. The results are presented with mean velocity plots and turbulent kinetic energy contours. Comparisons are then made with results obtained using a finite difference computational scheme based on the k - e turbulence model. Good agreement was obtained between the computer code predictions and the experimental data. / Thesis / Master of Engineering (ME)

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This thesis deals with a one and two dimensional numerical modeling of a low-pressure DC glow discharge in argon gas. We develop two-component fluid model which uses the diffusion-drift theory for the gas discharge plasma and consists of continuity equations for electrons and ions, as well as Poisson equation for electric field. Numerical method is based on the control volume technique. Calculations are carried out in MATLAB environment. Computed results are compared with the classic theory of glow discharges and available experimental data.

Flows of fluids and solid particles through microchannels have a very wide range of applications in biological and medical science and engineering. Understanding the mechanism of microflows will help to improve the development of the devices and systems in those applications. The aim of this study is to develop a sophisticated simulation and analysis technique for the study of fluid-particle flow through microchannels. This work involves construction of mathematical models, development of analytical methods and numerical algorithms, and numerical investigation and analysis. / The study consists of three parts. The first part of the research focuses on the transient flow of an incompressible Newtonian fluid through a micro-annual with a slip boundary. The flow of the fluid is governed by the continuity equation and the Navier-Stokes equations, and is driven by the pressure field with a timevarying pressure gradient. By using the Fourier series expansion in time and Bessel functions in space, an exact solution is derived for the velocity field. The velocity solution is then used to obtain the exact solutions for the flow rate and the stress field. Based on the exact solutions, the influence of the slip parameter on the flow behaviour is then investigated. / The second part of the research focuses on the particle-fluid flow in microchannels. The transport of fluid in the vessel is governed by the continuity equation and the transient Navier-Stokes equations, while the motion of the particles is governed by Newton’s laws. The particle-wall and particle-particle interactions are modelled by the interacting forces, while the particle-fluid interaction is described by the fluid drag force. A numerical scheme based on the finite element method and the Arbitary Lagrangian-Eulerian method is developed to simulate the motion of the particles and the fluid flow in the vessels. The influence of boundary slip on the velocity field in the fluid is also investigated numerically. / Based on the work in the second part, the third part of the research focuses onthe control of the movement of particles in the fluid by applying an external magneticfield to the system. Maxwell’s equations are used to model the magnetic fieldgenerated by the external magnetic source, and a finite element based numericalscheme is developed to solve the underlying boundary value problem for the magneticflux density generated. From the computed flux density and magnetic vectorpotential, the magnetic forces acting on the particles are determined. These magneticforces together with the drag force and the particle-particle interacting forcesdominate the behaviour of the particle motion. A numerical scheme, similar to thatfor the second part of the research, is then developed to study the fluid-particle flowin microchannels under magnetic forces, followed by a numerical investigation onthe influence of the magnetic forces on the particle flow behaviour.

<p>  </p> <p>A three-dimensional isothermal multiphase flow transient CFD model simulation of the comprehensive chemical processes, including desulfurization and reoxidation in a gas-stirred ladle during the secondary refinement process, has been investigated. The multiphase interactions and turbulence flow among steel, slag, and gas inside a ladle are simulated based VOF multiphase model and discrete model (DPM) in Fluent commercial software. A widely used theory describing the desulfurization and reoxidation processes, (Al2O3) -[O] equilibrium theory, is introduced into the model. The compositions of both steel and slag are monitored, and the mass fractions of each species in steel and slag are compared with the industrial data. There are two main stages for this study.</p> <p>In the first stage, the CFD model of an 80-ton ladle is developed to simulate both the flow field and reaction rates based on literature work. Then the predicated species contents are validated with industrial measurement, which proves the accuracy of the CFD model.</p> <p>The validated CFD model is applied to a Nucor Decatur two plugs bottom injection ladle in the second stage. There are two different plug separation angle scenarios: 90° and 180°, investigated in this part. Three argon gas flow rate combinations ((5/5 SCFM, 5/20 SCFM, and 20/20 SCFM) were employed. The slag eye size was validated with plant measurement. The results show that the desulfurization rate and reoxidation rate are promoted with a higher argon injection rate. When the argon injection rate is fixed, a larger separation angle improves the reaction rates.</p>