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1 
Finite volume methods and adaptive refinement for tsunami propagation and inundation /George, David L., January 2006 (has links)
Thesis (Ph. D.)University of Washington, 2006. / Vita. Includes bibliographical references (p. 181188).

2 
Thermofluid modeling and robust control of modern optic fiber drawing processesWei, Zhiyong. January 2004 (has links) (PDF)
Thesis (Ph. D.)Mechanical Engineering, Georgia Institute of Technology, 2004. / KokMeng Lee, Committee Chair ; Andrei G. Fedorov, Committee Member ; William E. Singhose, Committee Member ; David G. Taylor, Committee Member ; Zhi Zhou, Committee Member. Includes bibliographical references.

3 
Numerical study of linear and nonlinear problems using twofluid plasma model in one dimensionMantravadi, Bhargav 04 1900 (has links)
The ideal twofluid plasma model is a more generalized plasma model compared to the ideal MHD and it couples the ion and electron Euler equations via Maxwell's equations. Twofluid plasma model is essential when the ion and electron fluids are at different temperatures. In this work, a fundamental investigation on the effect of nondimensional light speed, iontoelectron mass ratio and plasma beta on the plasma dynamics in the BrioWu shock tube Riemann problem is presented. A one dimensional finite volume code is developed based on the macroscopic governing equations, with second order accuracy in space and time. The source terms are treated implicitly and the homogeneous flux terms are treated explicitly. The credibility of the numerical results is assessed by performing several linear and nonlinear tests.
Realistic light speed results in increasing the stiffness of the equations and severe time step restriction, which poses a challenge to the numerical simulations. In the context of the BrioWu shock tube problem, it is observed that the light speed is not important with respect to the hydrodynamics. However, light speed does affect the magnitude of the self generated electric field. Mass ratio affects the electron plasma dynamics. The speed of the fast moving electron plasma waves changes with the mass ratio. The results obtained using a mass ratio of 500 are in close agreement with that of realistic mass ratio of 1836. Increasing plasma beta suppresses the amplitude of the fast moving electron plasma waves.

4 
Development of numerical code for the study of Marangoni convectionMelnikov, Denis 14 May 2004 (has links)
A numerical code for solving the timedependent incompressible 3D NavierStokes equations with finite volumes on overlapping staggered grids in cylindrical and rectangular geometry is developed. In the code, written in FORTRAN, the momentum equation for the velocity is solved by projection method and Poisson equation for the pressure is solved by ADI implicit method in two directions combined with discrete fast Fourier transform in the third direction. A special technique for overcoming the singularity on the cylinder's axis is developed. This code, taking into account dependence upon temperature of the viscosity, density and surface tension of the liquid, is used to study the fluid motion in a cylinder with free cylindrical surface (under normal and zerogravity conditions); and in a rectangular closed cell with a source of thermocapillary convection (bubble inside attached to one of the cell's faces). They are significant problems in crystal growth and in general experiments in fluid dynamics respectively. Nevertheless, the main study is dedicated to the liquid bridge problem.
The development of thermocapillary convection inside a cylindrical liquid bridge is investigated by using a direct numerical simulation of the 3D, timedependent problem for a wide range of Prandtl numbers, Pr = 0.01  108. For Pr > 0.08 (e.g. silicon oils), above the critical value of temperature difference between the supporting disks, two counter propagating hydrothermal waves bifurcate from the 2D steady state. The existence of standing and traveling waves is discussed. The dependence of viscosity upon temperature is taken into account. For Pr = 4, 0g conditions, and for Pr = 18.8, 1g case with unit aspect ratio an investigation of the onset of chaos was numerically carried out.
For a Pr = 108 liquid bridge under terrestrial conditions , the appearance and the development of thermoconvective oscillatory flows were investigated for different ambient conditions around the free surface.
Transition from 2D thermoconvective steady flow to a 3D flow is considered for lowPrandtl fluids (Pr = 0.01) in a liquid bridge with a noncylindrical free surface. For Pr < 0.08 (e.g. liquid metals), in supercritical region of parameters 3D but nonoscillatory convective flow is observed. The computer program developed for this simulation transforms the original nonrectangular physical domain into a rectangular computational domain.
A study of how presence of a bubble in experimental rectangular cell influences the convective flow when carrying out microgravity experiments. As a model, a real experiment called TRAMP is numerically simulated. The obtained results were very different from what was expected. First, because of residual gravity taking place on board any spacecraft; second, due to presence of a bubble having appeared on the experimental cell's wall. Real data obtained from experimental observations were taken for the calculations.

5 
Development and applications of a fullstress flowband model for ice using the finite volume method /Price, Stephen F., January 2006 (has links)
Thesis (Ph. D.)University of Washington, 2006. / Vita. Includes bibliographical references (leaves 149159).

6 
Modeling of the Stator of Piezoelectric Traveling Wave Rotary Ultrasonic MotorsBolborici, Valentin 01 March 2010 (has links)
This thesis is concerned with the modeling of the stator of a piezoelectric traveling wave rotary ultrasonic motor. Existing models for piezoelectric traveling wave rotary ultrasonic motors are either too complicated to be used in motor control or do not reflect the real behavior of the motor and are of limited use in developing a controller for the motor.
Finite Element methods have been used in the past to examine the properties of piezoelectric structures however, the Finite Volume Method has always been ruled out without justification. The main goal of this thesis is to provide a Finite Volume modeling approach for the stator of the piezoelectric traveling wave rotary ultrasonic motor taking into account the basic theoretical principles from piezoelectricity and structural mechanics. This model can in future be extended to develop a complete model of the motor in addition to other piezoelectric structures.
The Finite Volume Method is shown to have the following specific advantages over the Finite Element Method especially for structures with simple geometries: 1. the Finite Volume Method respects the PDEs conservation law structure due to the fact that the fluxes are conserved between cells/domains/subregions, 2. the Finite Volume Method involves only surface integrals thus making it easier to implement a rotorstator contact model as the contact mechanism occurs at the boundary of the stator, and 3. the Finite Volume Method yields a system of ODEs that more intuitively map onto circuit simulation software.
The Finite Volume Method is initially used to model a simple piezoelectric plate. A corresponding circuit of the piezoelectric plate model, based on the Finite Volume Method, is generated. Two additional but more complex models are considered: one for a unimorph plate and one for the stator of an ultrasonic motor. The modeling results obtained with the Finite Volume Method are validated by comparing them with the results obtained with Finite Element simulations performed with COMSOL. Two test platforms designed to test and validate the Finite Volume and COMSOL results for the simple piezoelectric plates and piezoelectric traveling wave rotary ultrasonic motors are also presented in this thesis.

7 
Modeling of the Stator of Piezoelectric Traveling Wave Rotary Ultrasonic MotorsBolborici, Valentin 01 March 2010 (has links)
This thesis is concerned with the modeling of the stator of a piezoelectric traveling wave rotary ultrasonic motor. Existing models for piezoelectric traveling wave rotary ultrasonic motors are either too complicated to be used in motor control or do not reflect the real behavior of the motor and are of limited use in developing a controller for the motor.
Finite Element methods have been used in the past to examine the properties of piezoelectric structures however, the Finite Volume Method has always been ruled out without justification. The main goal of this thesis is to provide a Finite Volume modeling approach for the stator of the piezoelectric traveling wave rotary ultrasonic motor taking into account the basic theoretical principles from piezoelectricity and structural mechanics. This model can in future be extended to develop a complete model of the motor in addition to other piezoelectric structures.
The Finite Volume Method is shown to have the following specific advantages over the Finite Element Method especially for structures with simple geometries: 1. the Finite Volume Method respects the PDEs conservation law structure due to the fact that the fluxes are conserved between cells/domains/subregions, 2. the Finite Volume Method involves only surface integrals thus making it easier to implement a rotorstator contact model as the contact mechanism occurs at the boundary of the stator, and 3. the Finite Volume Method yields a system of ODEs that more intuitively map onto circuit simulation software.
The Finite Volume Method is initially used to model a simple piezoelectric plate. A corresponding circuit of the piezoelectric plate model, based on the Finite Volume Method, is generated. Two additional but more complex models are considered: one for a unimorph plate and one for the stator of an ultrasonic motor. The modeling results obtained with the Finite Volume Method are validated by comparing them with the results obtained with Finite Element simulations performed with COMSOL. Two test platforms designed to test and validate the Finite Volume and COMSOL results for the simple piezoelectric plates and piezoelectric traveling wave rotary ultrasonic motors are also presented in this thesis.

8 
Turbulent Flow and Transport Modeling by Long Waves and CurrentsKim, Dae Hong 2009 August 1900 (has links)
This dissertation presents models for turbulent flow and transport by currents
and long waves in large domain.
From the NavierStokes equations, a fully nonlinear depthintegrated equation
model for weakly dispersive, turbulent and rotational flow is derived by a perturbation
approach based on long wave scaling. The same perturbation approach is applied
for the derivation of a depthintegrated transport equation. As the results, coherent
structures generated by the turbulence induced by the bottom friction and topography
can be predicted very reasonably.
The three dimensional turbulence effects are incorporated into the flow model by
employing a back scatter model. The back scatter model makes it possible to predict
turbulent transport: It contributes to the energy transport and the lateral turbulent
diffusion through relying on the turbulent intensity, not by relying on an empirical
diffusion constant. The inherent limitation of the depthintegrated transport equation,
that is, the limitation for the near field prediction is recognized in the derivation
and the numerical simulation.
To solve the derived equation set, a highly accurate and stable finite volume
scheme numerical solver is developed. Thus, the numerical solver can predict dispersive
and nonlinear wave propagation with minimal error. Also, good stability is
achieved enough to be applied to the dambreak flows and undular tidal bores. In addition, a robust moving boundary scheme based on simple physical conditions is
presented, which can extend the applicability area of the depthintegrated models.
By the comparison study with experimental data, it is expected that the numerical
model can provide high confidence results for the wave and current transformations
including shocks and undular bores on complex bathymetry and topography. For
the accurate near field transport prediction, a three dimensional transport model in
?coordinate coupled with the depthintegrated flow model is developed. Like the
other models, this model is also intended for large domain problems, and yet efficient
and accurate in the far field and near field together.

9 
A Multidimensional Fitted Finite Volume Method for the BlackScholes Equation Governing Option PricingHung, ChenHui 05 July 2004 (has links)
In this paper we present a finite volume method for a twodimensional BlackScholes equation with stochastic volatility governing European option pricing. In this work, we first formulate the BlackScholes equation with a tensor (or matrix) diffusion coefficient into a conversative form. We then present a finite volume method for the resulting equation, based on a fitting technique proposed for a onedimensional BlackScholes equation. We show that the method is monotone by proving that the system matrix of the discretized equation is an Mmatrix. Numerical experiments, performed to demonstrate the usefulness of the method, will be presented.

10 
Prediction of mass transfer performance of microchannel dialyzers using deconvolution of impulseresponse experiments /Anderson, Eric K. January 1900 (has links)
Thesis (M.S.)Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 7778). Also available on the World Wide Web.

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