Thesis (M.S.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 138-141). Also available on the World Wide Web.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1968. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Dissertation (Ph.D.) -- Worcester Polytechnic Institute. / Keywords: Multiphase flow; Two-fluid modeling; Direct numerical simulation; Two fluid modeling. Includes bibliographical references (leaves 116-119).

Thesis (M.S.) -- Worcester Polytechnic Institute. / Keywords: Front tracking method; Level set method. Includes bibliographical references (leaves 51-52).

The aim of this dissertation is to demonstrate the potential of novel measurement techniques based on the scanning of gamma-ray transmission in the investigation of axially-symmetric flow properties of granular materials in 3D hoppers. Furthermore, the results of the experimental investigations are compared on a strictly quantitative basis with Newtonian Dynamics (i.e. Discrete Element simulations) and Molecular Dynamics (i.e. kinetic gas theory calculations). Measurements were performed using two specially constructed scanner systems of different geometric configuration of gamma-ray sources and detectors(namely parallel and fan beam arrangements respectively). The fan beam scanner has been developed entirely in the Department of Chemical & Process Engineering by the author of this thesis and therefore a significant part of the thesis deals with major points concerning both hardware and software development as well as associated calibration procedures. Gas-phase continuous mono-disperse systems have been studied using (i) the full tomographic imaging technique which is able to produce 3D planar maps of voidage at selected heights of a storage vessel and (ii) the single profile absorptiometric technique capable of producing voidage profiles in both Cartesian and polar coordinates at much faster acquisition rates. Results were compared with earlier Distinct Element numerical simulations showing encouraging agreement in terms of both the absolute values of voidage and their spatial fluctuations as well as the geometric structure of the static and dynamic particle assemblies. Size segregation in air borne binary mixtures have been quantified using the novel dual energy photon technique which is capable of producing solids fraction profiles for each of the individual components of a binary mixture in addition to the voidage profiles. Spatial and temporal data on solids fractions in a binary mixture were analysed using methodology based on statistical mechanics principles which led to the definition of "micro-turbulence" during flow in terms of the self-diffusion velocities of individual solid components. This then allows the calculation of both the self- and mutual-diffusion coefficients used to quantify size segregation. These calculations were also compared with theoretical predictions based on the kinetic gas theory which was found to grossly over-predict the calculated diffusion coefficients in slow-shearing granular flows.

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This thesis presents an experimental study and numerical predictions of the separated-reattaching flow around a bluff rectangular section. This laboratory configuration, chosen for its geometric simplicity, exhibits all main features of two-dimensional flow separation with reattachment. Detailed turbulent flow measurements of the mean and fluctuating flow field are reported. The measurement techniques used are: hot-wire anemometry, pulsed-wire anemometry and pulsed-wire surface shear stress probes. The separated shear layer appears to behave like a conventional mixing layer over the first half of the separation bubble, but exhibits a lower growth rate and higher turbulent intensities in the second half. In the reattachment region, the flow is found to be highly turbulent and unsteady. A finite difference method is used, in conjunction with a modified version of the TEACH code, to predict the mean flow field. Two discretization schemes are used: the hybrid-upwind differencing (HD) scheme, and the bounded-skew-hybrid differencing (BSHD) scheme. Laminar flow computations are performed for Reynolds numbers in the range 100 to 325. The HD computations underpredict the separation-bubble length by up to 35% as a result of false diffusion. The BSHD predictions, on the other hand, are in excellent agreement with the experimental results reported in the literature. Turbulent flow computations using the ƙ - ∈ turbulence model and the BSHD scheme result in a reattachment length about 30% shorter than the present measured value. When a curvature correction is incorporated into the model, a reattachment length of 4.3.D, compared to the experimental value of 4.7D, is predicted. The predicted mean flow, turbulent kinetic energy field and pressure distribution are in good agreement with experimental observations. An alternative method of analysis, based on the momentum integral technique, is presented. The method is not applied to the blunt-rectangular plate problem, but its use is illustrated for the simpler case of the flow in a sudden expansion, and promising results are obtained. / Applied Science, Faculty of / Mechanical Engineering, Department of / Graduate

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