Computational fluid dynamics or CFD isan importanttool thatis used at various stages in the design of highly complex turbomachinery such as compressorand turbine stages that are used in land and air based power generation units. The ability of CFD to predict the performance characteristics of a specific blade design is challenged by the need to use various turbulence models to simulate turbulent flows as well as transition models to simulate laminar to turbulent transition that can be observed in various turbomachinery designs. Moreover, CFD is based on numerically solving highly complex differential equations, which through the use of a grid to discretize the geometry introduces numerical errors. Allthese factors combine to challenge CFD’s role as a predictor of blade performance. It has been generallyfound that CFD in its current state of the art is best used to compare between various design points and not as a pure predictor of performances. In this study the capability of CFD, and turbulence modeling, in turbomachinery based geometry is assessed.Three different blade designs are tested, that include an advanced two-stage turbine blade design, a three stage 2D or cylindrical design and finally a three stage bowed stator and rotor design. Allcases were experimentally tested at the Texas A&Muniversity Turbomachinery Performance and Flow Research Laboratory (TPFL).In all cases CFD provided good insights into fundamental turbomachinery flow physics, showing the expected improvement from using 2D cylindrical blades to 3D bowed blade designs in abating the secondary flow effects which are dominant loss generators.However, comparing experimentally measured performance results to numerically predicted shows a clear deficiency, where the CFD overpredicts performance when compared to experimentallyobtained data, largely underestimating the various loss mechanisms. In a relative sense, CFD as a tool allows the user to calculate the impact a new feature or change can have on a baseline design. CFD will also provide insight into what are the dominant physics that explain why a change can provide an increase or decrease in performance. Additionally,as part of this study, one of the main factors that affect the performance of modern turbomachinery is transition from laminar to turbulent flow.Transition is an influential phenomena especially in high pressure turbines, and is sensitive to factors such asupstream incidentwake frequency and turbulence intensity.A model experimentally developed, is implemented into a CFD solver and compared to various test results showing greater capability in modeling the effects of reduced frequency on the transition point and transitional flow physics. This model is compared to industry standard models showing favorable prediction performance due to its abilityto account for upstream wake effects which most current model are unable to account for.

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Thesis (Ph. D.)--University of Hawaii at Manoa, 1996. / Includes bibliographical references (leaves 227-232). / Microfiche. / xiii, 232 leaves, bound ill. (some col.) 29 cm

Thesis (Ph. D.)--University of Oregon, 2003. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 271-279). Also available for download via the World Wide Web; free to University of Oregon users.

Thesis (Ph. D.)--Lehigh University, 2006. / Includes vita. Includes bibliographical references (leaves 72-76).

We discuss how to realize simple Smale Flows on 3-manifolds. We focus on three questions: (1) What are the topological conjugate classes of Lorenz Smale flows that can be realized on S3? (2) Which 3-manifolds can also admit a Lorenz Smale flow? (3) What are the topological conjugate classes of simple Smale flows whose saddle set can be modeled by &nu(0+,0+,0,0) can be realized on S3? This dissertation extends the work of M. Sullivan and B. Yu.

In this dissertation, we discuss how to realize simple Smale flows on 3-manifolds. We use four-band and three-band templates to study the linking structure of two types of closed orbits known as attracting closed orbits and repelling closed orbits in the flow. This dissertation extends the work done by M. Sullivan on realizing Lorenz Smale flows on 3-manifolds, by Bin Yu on realizing Lorenz-like Smale flows on 3-manifolds and continues the work of Elizabeth Haynes and Michael Sullivan on realizing simple Smale flows with a four-band template on a 3-sphere. The four-band template we use in this dissertation is different from the template used by Haynes and Sullivan.

We adapted the chord diagram plot to visualize China's recent inter-provincial migration during 2010-2015. The arrowheads were added to present the direction of the flows. This method allows us to show the complete migration flows between 31 provinces in China including the direction and volume of the flows. The spatial component was also clearly depicted in the plot using four color palates representing four regions in China (i.e. East, Center, West, Northeast) and arranging the 31 provinces in an approximate geographic order. Besides that, we extend the chord diagram plot to describe China's bilateral net migration during 2010-2015.