Siu Yuet Lun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves [51]-54). / Text in English; abstracts in English and Chinese. / Siu Yuet Lun. / Abstract --- p.i / Acknowledgments --- p.ii / Contents --- p.iii / List of Figures --- p.v / List of Tables --- p.vii / Chapter Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- What is an electrorheological fluid? --- p.1 / Chapter 1.2 --- Overview of recent theoretical studies of ER fluids --- p.2 / Chapter 1.3 --- Objectives of the thesis --- p.3 / Chapter Chapter 2. --- Justification of the DID model --- p.5 / Chapter 2.1 --- Review of the multiple image method --- p.6 / Chapter 2.1.1 --- The development of the multiple image method --- p.6 / Chapter 2.1.2 --- Image dipole --- p.7 / Chapter 2.1.3 --- Total dipole moment --- p.8 / Chapter 2.2 --- Comparison of the multiple image method with the Klingenberg's force functions --- p.11 / Chapter 2.3 --- Interparticle force in polydisperse ER fluids --- p.16 / Chapter Chapter 3. --- Computer simulations of ER fluids in the DID model --- p.22 / Chapter 3.1 --- The natural scales in the simulation --- p.23 / Chapter 3.2 --- The aggregation for a pair of spheres --- p.25 / Chapter 3.2.1 --- In uniaxial field --- p.25 / Chapter 3.2.2 --- In rotating field --- p.28 / Chapter 3.3 --- The aggregation for three and four spheres in the rotating field --- p.31 / Chapter Chapter 4. --- Computer simulation of morphology in the DID model --- p.35 / Chapter 4.1 --- Hard-core repulsion --- p.35 / Chapter 4.2 --- Periodic boundary conditions --- p.36 / Chapter 4.3 --- Morphology in DID model and PD model --- p.38 / Chapter Chapter 5. --- Conclusion --- p.43 / Chapter Appendix A. --- Analytic results of the equation of motion --- p.44 / Chapter A.1 --- Analytic solution for two spheres --- p.45 / Chapter A.2 --- Analytic solution for three spheres in a chain --- p.45 / Chapter A.3 --- Analytic solution for three spheres in an equilateral triangle --- p.47 / Chapter A.4 --- Analytic solution for four spheres in a square --- p.48 / Chapter Appendix B. --- Table of values of the time steps --- p.50 / Bibliography --- p.51

In a fluidized bed of magnetically susceptible particles, the presence of a magnetic field induce the formation of particle chains due to interparticle magnetic forces. The resulting effect is a change in the overall spatial distribution of the particles, transitioning from a random, isotropic distribution to an ordered, anisotropic distribution. For a magnetic field with the same direction as the superficial fluid velocity, the resulting structures offer less resistance to flow, resulting in a decrease of the effective drag coefficient. Thus the bed is less expanded and have lower voidage in the presence of the magnetic field, at a given fluid superficial velocity. The effect of particle chaining in the particle drag in a liquid-solid fluidized bed is studied. Experimental data is collected on voidage and pressure drop for particle Reynolds number between 75 and 190, and for particle chain separation force to buoyant weight ratio between 0 and 0.58. A two-parameter equation for the change in drag coefficient with respect to the hydrodynamic and magnetic operating conditions in the bed is obtained. It provides very good agreement with the experimental data. A proprietary 3-D simulation code implementing a Computational Fluid Dynamics-Discrete Particle Method is developed and tested under the same conditions as the experiments performed. Without the use of any correction in the drag coefficient, the simulation code overestimates the bed expansion by as much as 70%. This error is reduced to or below 10% when the drag coefficient is corrected using the equation here obtained. / Graduation date: 2005

Previous studies in Magnetically Stabilized Fluidized Bed (MSFB) are well known for conventional two-phase, gas-solid or liquid-solid fluidization. Many researchers have investigated the fluid dynamic behavior of the MSFB, however, all of these studies are based on a uniform magnetic field that is constant throughout the bed column. Currently, there are no references in the open literature indicating either fundamental or applied research with a magnetically fluidized bed where a non-uniform magnetic field is used in a two-phase liquid-solid fluidization. In this study, the fluid dynamic behavior of a Magnetically Assisted Fluidized Bed (MAFB) in a non-uniform magnetic field is experimentally observed. In the MAFB, a magnetic force, F[sub m] , is created which acts on the ferromagnetic particles (20% ferrite) by varying the magnetic field intensity from the top to the bottom of the fluidization column. However, the field gradient is kept constant throughout the bed. Because of the differences in the magnetic field intensity at any location in the bed, the particle holdup, or inversely the bed voidage, has to change to accommodate the equilibrium of forces acting on the particles (drag force, gravitational force, buoyancy force, and magnetic force). In the laboratory experiments, performed magnetic field gradient, [see PDf for equation] Alm/m, -18,289 Alm/m, -20,543 Alm/m and -33,798 A/m/m) and fluid flow rate (U[sub 0] =0.0153 m/s, 0.0176 m/s, 0.0199 m/s and 0.0222 m/s) are varied. These experiments show that the increase in the magnetic field gradient and the magnetic field intensity results in the decrease in the height of the bed, and therefore, in the decrease of the bed voidage. The dynamic pressure drop, [delta]P[sub f][sub(d)], is also experimentally measured, then converted to a corresponding voidage. The relationship between the dynamic pressure drop and the bed voidage is given by the following equation:[see PDF for equation] The fluid dynamic behavior of the MAFB is described by the equation of motion and the equation of continuity for both liquid and solid phases. A mathematical model is developed and used to evaluate the voidage distribution in the MAFB. The resulting expression for the voidage distribution in the MAFB is given as [see PDF for equation]. Experimentally obtained bed voidage data in both, laboratory experiments (1g) and on board of the NASA KC-135 plane (0g) fit very well the above equation which does not have any adjustable parameter. / Graduation date: 2001

Thesis (Ph. D.)--University of Nevada, Reno, 2005. / "December 2005." Includes bibliographical references (leaves 155-166). Online version available on the World Wide Web. Library also has microfilm. Ann Arbor, Mich. : ProQuest Information and Learning Company, [2005]. 1 microfilm reel ; 35 mm.

Thesis (Ph. D.)--Oregon Graduate Center, 1973.

Graduation date: 1990

.La tesi analitza les dinàmiques no locals i la intermitència en fluids no homogenis i no isotròpics tant en experiments de laboratori com en dades geogràfiques. Després de l'estudi sobre els models que descriuen la intermitència en fluids homogenis i isotròpics, presentem un model per fluids no homogenis i no isotropics. El model es basa en l'anàlisi de la jerarquia de transmissió d'energia. S'utilitza la tècnica de la Extended Self Similarity amb l'objectiu d'estudiar l'escala de lleis de les funcions estructurals de velocitat. Els resultats experimentals de tres tipus de fluids que s'han comparat amb el model per fluids no homogenis i no isotròpics són els següents: turbulència generada per un cilindre en un canal de vent i turbulència generada per una reixa i per un jet en un canal d'aigua. S'analitza la turbulència geogràfica del Delta de l'Ebre i del Knebel Vig i els resultats són comparats amb els del model anteriorment esmentat. La contribució principal és el descobriment d'un paràmetre aparentment relacionat amb la jerarquia de transmissió d'energia en el rang inercial que juga un paper clau en la comprensió de les dinàmiques dels fluids no homogenis. / .The thesis analyze the non-local dynamics and intermittency in non-homogeneous and non-isotropic flows both in the laboratory experiments and geophysical data. After a review on models describing intermittency in homogeneous and isotropic flows, a different model for non-homogeneous and non-isotropic flows is introduced. A model is based on the analysis of the energy transfer hierarchy. The technique of Extended Self Similarity is used to study the scaling laws of the velocity structure functions. Experimental results of three type of flows cylinder wake turbulence in wind tunnel, grid and jet turbulence in water channel are presented and compared with the model. The geophysical turbulence in the Ebro Delta and Knebel Vig are analyzed and the results are compared with the model. The important contribution is the discovery of a new apparently parameter related to the energy transfer hierarchy in the inertial range which plays a key role in the understanding of the dynamics of the non-homogeneous flows.

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 237-250). Available also in a digital version from Dissertation Abstracts.

Thesis (M.S.)--University of Missouri-Columbia, 2003. / Typescript. Includes bibliographical references (leaves 50-51). Also available on the Internet.

Thesis (M.S.)--University of Missouri-Columbia, 2003. / Typescript. Includes bibliographical references (leaves 50-51). Also available on the Internet.