Thesis (Ph. D.)--Missouri University of Science and Technology, 2009. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed June 2, 2009) Includes bibliographical references (p. 115-126).

Thesis (M.S.) -- Mississippi State University. Department of Aerospace Engineering. / Title from title screen. Includes bibliographical references.

Thesis (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2016. / This work presents the computational uid dynamics (CFD) analysis of a light road vehicle. Simulations are conducted using the lattice Boltzmann method (LBM) with the wall adapting local eddy (WALE) turbulence model. Simulations include and compare the use of a rolling road, rotating wheels, adaptive re nement as well as showing comparison with a Reynolds-averaged Navier-Stokes (RANS) solver and the Spalart- Allmaras (SA) turbulence model. The lift coe cient of the vehicle for the most part was seen to show a much greater di erence and inconsistencies when compared to drag from the comparisons of solvers, turbulence models, re nement and the e ect of rolling road. Determining the drag of a road vehicle can be easily achieved and veri ed using multiple solvers and methods, however, the lift coe cient and its validation require a greater understanding of the vehicle ow eld as well as the solvers, turbulence models and re nement levels capable of correctly simulating the turbulent regions around a vehicle. Using the presented method, it was found that the optimisation of vehicle aerodynamics can easily be done alongside the design evolution from initial low-drag shapes to the nal detail design, ensuring aerodynamic characteristics are controlled with aesthetic change.

Orientador: José Roberto Nunhez / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-19T04:29:50Z (GMT). No. of bitstreams: 1 Souza_Edimilson_D.pdf: 42879503 bytes, checksum: f045a81ccffc27a6b322cd000bb460cd (MD5) Previous issue date: 2011 / Resumo: O projeto de agitadores envolve um grande número de variáveis, além da necessidade de utilização das relações empíricas para que se possa elaborar um projeto eficiente. Em função do grande número de variáveis envolvidas, muitas opções ainda carecem de estudos científicos e bibliografias que deem segurança aos projetistas, como é o caso dos impelidores do tipo disco dispersor, para altas dispersões, com característica predominantemente de alto cisalhamento, também conhecidos como: impelidores dentados, dentes de serra ou simplesmente Cowles. O estudo passa inicialmente pelo entendimento amplo dos conceitos de agitação e mistura, tais como: regime de escoamento em tanques agitados, fluidos, nível de agitação, processos de agitação e mistura, geometrias de tanques, tipos e geometria dos impelidores, número de bombeamento e número de potência. Comparou-se resultados de número de potência obtidos nos ensaios com teoria de autores consagrados para impelidores de pás retas. Obteve-se de forma experimental as equações do torque em função da rotação e as curvas do número de potência em função do número de Reynolds para impelidores do tipo disco dispersores de diversas geometrias, trabalhando com dois métodos de medição de torque: transdutor de torque e parâmetros elétricos, utilizando unidade piloto de 50 e 1000 L, assim como indica o número de potência determinado para oitenta e oito impelidores ensaiados / Abstract: The design of impellers involves a great number of variables, as well as the use of empirical correlations to enable an efficient design. Due to the great number of variables involved, many design options lack a deeper scientific basis and broader literature information that would provide the engineer with a more understanding to elaborate a more efficient design. This is the case for impellers used in dispersions, where the main impeller characteristic are their high shear. These impellers are also known as toothed impellers or Cowles impellers. This study starts with the acquiring of a deeper understanding of .mixing processes using high shear impellers with the corresponding concepts of agitation level, tank geometry, impeller geometry, Pumping and Power numbers. The Power number obtained in this work was compared with the published results of previous authors for flat blade impellers. The correlations for torque as a function of impeller speed and the Power number for several impeller disperses as a function or Reynolds number were obtained through a torque transducer and electrical parameters using both a 50 L and a 100 L pilot plants. The experimental Power number of eighty eight impellers was determined in this work / Doutorado / Processos em Tecnologia Química / Doutor em Engenharia Química

At small length scales, low velocities, and high viscosity, the effects of inertia on motion through fluid become insignificant and viscous forces dominate. Microswimmer propulsion, of necessity, is achieved through different means than that achieved by macroscopic organisms. We describe in detail the hydrodynamics of microswimmers consisting of colloidal particles and their interactions. In particular we focus on two-bead swimmers and the effects of asymmetry on collective motion, calculating analytical formulae for time-averaged pair interactions and verifying them with microscopic time-resolved numerical simulation, finding good agreement. We then examine the long-term effects of a swimmer's passing on a passive tracer particle, finding that the force-free nature of these microswimmers leads to loop-shaped tracer trajectories. Even in the presence of Brownian motion, the loop-shaped structures of these trajectories can be recovered by averaging over a large enough sample size. Finally, we explore the phenomenon of synchronisation between microswimmers through hydrodynamic interactions, using the method of constraint forces on a force-based swimmer. We find that the hydrodynamic interactions between swimmers can alter the relative phase between them such that phase-locking can occur over the long term, altering their collective motion.

Interaction of flow structures from a three-cylinder system is complex and important for fundamental and engineering applications. In this study, experiments using hotwire, 2D PIV, and Tomography are to be conducted to characterize the fluid flow at various Re number and rotation speeds. The Reynolds number considered based on the diameter of the single-cylinder ranges from 37 to 1700. The peaks in the frequency spectrum obtained from the hotwire study show a unique relation of Strouhal number as a function of static incident angle, RPM, and Reynolds number. From the 2D PIV and 3D tomography experiment, vorticity and velocity results characterize the interaction of wake flow from individual cylinders and as a function of the rotational speeds. Besides, the Standard deviation map shows the turbulence intensity variation at the various static and rotating conditions. The obtained results at static conditions are found to be consistent with the previous computational study.

Master thesis deals with the analysis of wind effect on high slender engineering structures. There are explained important knowledge of the flow theory and compared each turbulent models according to relation of Reynolds and Strouhal number. The point of separation i salso defined. All necessary calculations are made in the ANSYS systém.

MSc (Mathematics) / Department of Mathematics and Applied Mathematics / See the attached abstract below

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