Tsunamis are gravity water waves that are generated by impulsive disturbances such as submarine earthquakes, landslides, volcanic eruptions, underwater explosions or asteroid impacts. Submarine earthquakes are the primary tsunami source, but landslides may generate tsunamis exceeding tectonic tsunamis locally, in both wave and runup heights. The field data on landslide tsunami events are limited, in particular regarding submarine landslide dynamics and wave generation. Tsunamis generated by three-dimensional deformable granular landslides are physically modeled in the NEES (Network of Earthquake Engineering Simulation) 3D tsunami wave basin (TWB) at Oregon State University in Corvallis, Oregon. A novel pneumatic landslide tsunami generator is deployed to simulate natural landslide motion on a hill slope. The instrumentation consists of various underwater, above water and particle image velocimetry (PIV) cameras, numerous wave and runup gauges and a multi-transducer acoustic array (MTA). The subaerial landslide shape and kinematics on the hill slope and the surface elevation of the offshore propagating tsunami wave and runup on the hill slope are measured. The evolution of the landslide front velocity, maximum landslide thickness and width are obtained along the hill slope. The landslide surface velocity distribution is obtained from the PIV analysis of the subaerial landslide motion. The shape and the size of the submarine landslide deposit are measured with the MTA. Predictive equations are obtained for the tsunami wave amplitude, wave period and wavelength in terms of the non-dimensional landslide parameters. The generated 3D tsunami waves propagate away from the landslide source as radial wave fronts. The amplitudes of the leading tsunami waves decay away from the landslide source in radial and angular direction. The wave celerity of the leading tsunami wave may be approximated by the solitary wave speed while the trailing waves are slower due to the dispersion effects. The energy conversion rate between the landslide and the generated wave is estimated. The observed waves are weakly non-linear in nature and span from shallow water to deep water depth regime. The unique experimental data serves the validation and advancement of numerical models of tsunamis generated by landslides. The obtained predictive equations facilitate initial rapid tsunami hazard assessment and mitigation.

An experimental program is designed to study the salient features of separated and reattached flows in pressure gradients generated in asymmetric diverging and converging channels. The channels comprised a straight flat floor and a curved roof that was preceded and followed by straight parallel walls. Reference measurements were also made in a parallel-wall channel to facilitate the interpretation of the pressure gradient flows. A transverse square rib located at the start of convergence/divergence was used to create separation inside the channels. In order to simplify the interpretation of the relatively complex separated and reattached flows in the asymmetric converging and diverging channels, measurements were made in the plain converging and diverging channel without the rib on the channel wall. All the measurements were obtained using a high resolution particle image velocimetry technique. The experiments without the ribs were conducted in the diverging channel at Reynolds number based on half channel depth (Reh) of 27050 and 12450 and in the converging channel at Reh = 19280. For each of these three test conditions, a high resolution particle image velocimetry technique (PIV) was used to conduct detailed velocity measurements in the upstream parallel section, within the converging and diverging section, and downstream of the converging and diverging sections. From these measurements, the boundary layer parameters and profiles of the mean velocities, turbulent quantities as well as terms in the transport equations for turbulent kinetic energy and Reynolds stresses were obtained to document the effects of pressure gradient on the flow. In the adverse pressure gradient case, the turbulent quantities were enhanced more significantly in the lower boundary layer than the upper boundary layer. On the other hand, favorable pressure gradient attenuated the turbulence levels and the effect was found to be similar on both the upper and the lower boundary layers. For the separated and reattached flows in the converging, diverging and parallel-wall channels at Reh = 19440, 12420 and 15350, respectively. The Reynolds number based on the approach velocity and rib height was Rek  2700. From these measurements, profiles of the mean velocities, turbulent quantities and the various terms in the transport equations for turbulent kinetic energy and Reynolds stresses were also obtained. The flow dynamics in the upper boundary layer in the separated region and the early stages of flow redevelopment were observed to be insensitive to the pressure gradients. In the lower boundary layer, however, the flow dynamics were entirely dominated by the separated shear layer in the separated region as well as the early region of flow redevelopment. The effects of the separated shear layer diminished in the redevelopment region so that the dynamics of the flow were dictated by the pressure gradients. The proper orthogonal decomposition (POD) was applied to educe the dominant large scale structures in the separated and reattached flows. These dominant scales were used to document structural differences between the canonical upstream flow and the flow field within the separated and redeveloping region. The contributions of these dominant structures to the dynamics of the Reynolds normal and shear stresses are also presented and discussed. It was observed that the POD recovers Reynolds shear stress more efficiently than the turbulent kinetic energy. The reconstruction reveals that large scales contribute more to the Reynolds shear stress than the turbulent kinetic energy.

abstract: Efficient performance of gas turbines depends, among several parameters, on the mainstream gas entry temperature. At the same time, transport of this high temperature gas into the rotor-stator cavities of turbine stages affects the durability of rotor disks. This transport is usually countered by installing seals on the rotor and stator disk rims and by pressurizing the cavities by injecting air (purge gas) bled from the compressor discharge. The configuration of the rim seals influences the magnitude of main gas ingestion as well as the interaction of the purge gas with the main gas. The latter has aerodynamic and hub endwall heat transfer implications in the main gas path. In the present work, experiments were performed on model single-stage and 1.5-stage axial-flow turbines. The turbines featured vanes, blades, and rim seals on both the rotor and stator disks. Three different rim seal geometries, viz., axially overlapping radial clearance rim seals for the single-stage turbine cavity and the 1.5-stage turbine aft cavity, and a rim seal with angular clearance for the single-stage turbine cavity were studied. In the single-stage turbine, an inner seal radially inboard in the cavity was also provided; this effectively divided the disk cavity into a rim cavity and an inner cavity. For the aft rotor-stator cavity of the 1.5-stage turbine, a labyrinth seal was provided radially inboard, again creating a rim cavity and an inner cavity. Measurement results of time-average main gas ingestion into the cavities using tracer gas (CO2), and ensemble-averaged trajectories of the purge gas flowing out through the rim seal gap into the main gas path using particle image velocimetry are presented. For both turbines, significant ingestion occurred only in the rim cavity. The inner cavity was almost completely sealed by the inner seal, at all purge gas flow rates for the single-stage turbine and at the higher purge gas flow rates for 1.5-stage turbine. Purge gas egress trajectory was found to depend on main gas and purge gas flow rates, the rim seal configuration, and the azimuthal location of the trajectory mapping plane with respect to the vanes. / Dissertation/Thesis / M.S. Mechanical Engineering 2010

abstract: Single cell phenotypic heterogeneity studies reveal more information about the pathogenesis process than conventional bulk methods. Furthermore, investigation of the individual cellular response mechanism during rapid environmental changes can only be achieved at single cell level. By enabling the study of cellular morphology, a single cell three-dimensional (3D) imaging system can be used to diagnose fatal diseases, such as cancer, at an early stage. One proven method, CellCT, accomplishes 3D imaging by rotating a single cell around a fixed axis. However, some existing cell rotating mechanisms require either intricate microfabrication, and some fail to provide a suitable environment for living cells. This thesis develops a microvorterx chamber that allows living cells to be rotated by hydrodynamic alone while facilitating imaging access. In this thesis work, 1) the new chamber design was developed through numerical simulation. Simulations revealed that in order to form a microvortex in the side chamber, the ratio of the chamber opening to the channel width must be smaller than one. After comparing different chamber designs, the trapezoidal side chamber was selected because it demonstrated controllable circulation and met the imaging requirements. Microvortex properties were not sensitive to the chambers with interface angles ranging from 0.32 to 0.64. A similar trend was observed when chamber heights were larger than chamber opening. 2) Micro-particle image velocimetry was used to characterize microvortices and validate simulation results. Agreement between experimentation and simulation confirmed that numerical simulation was an effective method for chamber design. 3) Finally, cell rotation experiments were performed in the trapezoidal side chamber. The experimental results demonstrated cell rotational rates ranging from 12 to 29 rpm for regular cells. With a volumetric flow rate of 0.5 µL/s, an irregular cell rotated at a mean rate of 97 ± 3 rpm. Rotational rates can be changed by altering inlet flow rates. / Dissertation/Thesis / Video of the irregular cell rotation / M.S. Bioengineering 2011

ALe travail réalisé dans le cadre de cette thèse en co-tutelle est à cheval entre deux domaines d’étude de l’interférence de sillage d’obstacle non profilé (soit un cylindre ou deux cylindres en tandem) et celle des zones de recirculations dans un sluice artisanal (un appareil de tri d’or). Notre étude contribue à l’étude des écoulements à surface libre par combinaison de quelques méthodes expérimentales. Nous avons couplé quelques techniques entre autres la visualisation de la topologie du sillage proche par la caméra CCD embarquée, les mesures des champs de vitesse par PIV et des efforts hydrodynamiques. Ainsi, le cylindre animé d’un mouvement uniformément accéléré/décéléré est caractérisé par les forces de traînée et de portance, les enveloppes des maximas, la longueur de le zone de recirculation et le nombre de Strouhal local. Dont ce dernier a une valeur avoisinant de 0.4 près de la surface libre. Et entre deux pics de la portance, le déferlement de la vague d’accompagnement est observable. L’interférence entre deux structures est simulée à travers deux cylindres et que sur une configuration symétrique, le paramètre de proximité B a tendance à accroître la longueur de la zone de recirculation. Les méthodes et dispositifs expérimentales décrites ci-dessus sont appliqués dans le cas d’écoulement hydrodynamique turbulent au sein du sluice. Les essais sur sites aurifères à Madagascar ont permis la collecte des informations sur les paramètres optimums du tri. Ces paramètres sont pris comme base initiale des travaux de laboratoire entamés sur une maquette à l’échelle 1. L’acquisition par PIV suivi des traitements statistique à multi-variables POD Snapshot nous a permis de créer un modèle expérimental de l’écoulement composé de 4 zones distinctes. L’étude expérimentale a été complétée par une simulation numérique par ANSYS14.5 ; qui nous a permis de conclure que l’approchement des riffles entraîne une diminution de la zone favorable du dépôt des minerais lourds. / Two major areas are focused in the thesis. The first investigates the interference due to a wake-pattern of non-profiled obstacles (such as one or two cylinder in tandem). The second characterizes the zone of recirculation inside an artisanal sluice-boxe, which is a device for gold extraction. The work contributes to the study of the flow of a free-surface using experimental methods. Also, a few approaches is combined for the investigation. In this regard, the near-wake pattern of the flow is examined using an embedded CCD camera, correlated to a PIV measurement of the velocity fields and the hydrodynamic forces. We found that a cylinder of uniform motion, accelerated or decelerated, is characterized by: the drag and the lift forces, the envelopes of maxima, the length of the recirculation zone and the local Strouhal number. The Strouhal number approaches the value of 0.4 next to a free-surface and a breaking wave is observed in-between two peaks of the lift force. We modeled the interference between two structures using a succession of two cylinders. The proximity parameter B tends to an increase of the recirculation length for a symmetrical arrangement.Our methods and the experimental procedures are applied for the examination of a turbulent hydrodynamic flow inside a sluice. Tests were performed on gold sites in Madagascar. This permitted the collection of information concerning the optimum parameters for an extraction. The obtained values form the basis of our laboratory work and are applied to a scaled model for validation. An experimental flow model, made of four distinct zones, is derived from a monitored PIV data and a statistical analysis of a multi-variable POD snapshot. The results are validated through simulations using the package ANSYS 14.5. The investigation shows that a closer riffles reduces the region for heavy minerals deposition.

Submitted by Jordan (jordanbiblio@gmail.com) on 2017-03-02T14:03:04Z No. of bitstreams: 1 DISS_2015_Larissa Alves Berté Barbosa.pdf: 410769 bytes, checksum: 903677a2ce06bd213b48a06034419b79 (MD5) / Approved for entry into archive by Jordan (jordanbiblio@gmail.com) on 2017-03-03T12:03:08Z (GMT) No. of bitstreams: 1 DISS_2015_Larissa Alves Berté Barbosa.pdf: 410769 bytes, checksum: 903677a2ce06bd213b48a06034419b79 (MD5) / Made available in DSpace on 2017-03-03T12:03:08Z (GMT). No. of bitstreams: 1 DISS_2015_Larissa Alves Berté Barbosa.pdf: 410769 bytes, checksum: 903677a2ce06bd213b48a06034419b79 (MD5) Previous issue date: 2015-03-19 / O hormônio de crescimento (GH) é um hormônio secretado pela hipófise e atua no crescimento de vários tecidos, incluindo a sistema reprodutor. Ele não é um hormônio reprodutivo, porém tem uma ligação importante para o desenvolvimento dos folículos ovarianos e no amadurecimento oocitário. Seus receptores estão presentes nas células do cumulus na membrana citoplasmática e nuclear do oócito, e isso faz com que o GH atue diretamente em seu crescimento. Na produção in vitro de embriões o GH vem sendo estudado visando aumentar a quantidade e a qualidade dos embriões, porém a concentração de GH na maturação in vitro ainda não está definida, havendo uma variação na literatura de 10 a 1000 ng/mL. Com isso, esse estudo comparou diferentes dosagens de GH adicionados ao meio de maturação, a fim de definir uma dosagem ideal para que haja um aumento na quantidade e qualidade dos embriões produzidos, que foi mensurada através das taxas de clivagem, produção de embriões e quantificação do número de células embrionárias, como também se comparou a interação do GH com a geração de estresse oxidativo. Os oócitos foram maturados com meio composto por TCM 199 com sais de Earl, suplementado com 10% de soro fetal bovino, hormônio luteinizante, hormônio folículo estimulante, estradiol e amicacina. Diferentes dosagens de GH foram adicionadas ao meio de maturação sendo elas 0 ng/mL, 25 ng/mL, 50 ng/mL, 75 ng/mL e 100 ng/mL. Após 24 horas de maturação os oócitos foram fertilizados e estes foram incubados por 22 horas, para posteriormente passarem para o cultivo, onde ficaram incubadas por 7 dias. No terceiro dia de cultivo foram avaliadas as clivagens e no sétimo dia a produção de embriões. Os embriões em estagio de blastocisto expandido foram fixados em lâmina e corados com Panótico para a contagem de células embrionárias. A análise de estresse oxidativo foi feito pela reação dos meios de maturação, fertilização e cultivo com o acido tiobarbitúrico. Houve diferenças significativas sobre a quantificação de células quando usado 100 ng/ml proporcionando uma melhora na qualidade dos embriões, e também se aumentou o estresse oxidativo quando usado 75 e 100 ng/mL na fertilização e no cultivo in vitro. / Growth hormone (GH) is a hormone secreted by the pituitary gland and acts on the growth of various tissues, including the reproductive system. It is not a reproductive hormone, but has an important link to the development of ovarian follicles and the oocyte maturation. Its receptors are present in cumulus cells in cytoplasmic and nuclear membrane of the oocyte, and this causes the GH acts directly in its growth. In vitro production of embryos GH has been studied to increase the amount and quality of embryos, but the concentration of GH in vitro maturation is not yet defined, with a variation in the literature 10 to 1000 ng/mL. This study compared different dosages of GH added to the maturation medium in order to set an optimal dosage so that there is an increase in the quantity and quality of embryos produced, which was measured by the cleavage rates, embryo production and quantifying the number of embryonic stem cells, as well as comparing the interaction of GH with the generation of oxidative stress. Oocytes were matured in medium composed of TCM 199 with Earl's salts, supplemented with 10% fetal bovine serum, luteinizing hormone, follicle stimulating hormone, estradiol, and amikacin. Different dosages of GH were added to maturation medium these being 0 ng/mL 25 ng /mL, 50 ng/mL, 75 ng/mL and 100 ng/mL. After 24 hours of maturation, oocytes were fertilized and these were incubated for 22 hours to later pass to the culture and they were incubated for 7 days. On the third day of cultivation were evaluated cleavages and on the seventh day the production of embryos. Embryos expanded blastocyst stage were fixed on slides and stained with Panotic for embryonic cell count. The oxidative stress analysis was done by the reaction of the means of maturation, fertilization and cultivation with thiobarbituric acid. There were significant differences in quantitation of cells when used 100 ng/mL giving an improvement in the quality of embryos, and also increased the oxidative stress used when 75 and 100 ng/mL in fertilization and in vitro culture.

No description available.

We investigate experimentally the turbulent flow through a two-dimensional contraction. Using a water tunnel with an active grid we generate turbulence at Taylor microscale Reynolds number Reλ ~ 250 which is advected through a 2.5:1 contraction. Volumetric and time-resolved Tomo-PIV and Shake-The-Box velocity measurements are used to characterize the evolution of coherent vortical structures at three streamwise locations upstream of, and within the contraction. We confirm the conceptual picture of coherent large-scale vortices being stretched and aligned with the mean rate of strain. This alignment of the vortices with the tunnel centerline is stronger compared to the alignment of vorticity with the large-scale strain observed in numerical simulations of homogeneous turbulence. We judge this by the peak probability magnitudes of these alignments. This result is robust and independent of the grid-rotation protocols. On the other hand, while the point-wise vorticity vector also, to a lesser extent, aligns with the mean strain, it principally remains aligned with the intermediate eigen-vector of the local instantaneous strain-rate tensor, as is known in other turbulent flows. These results persist when the distance from the grid to the entrance of the contraction is doubled, showing that modest transverse inhomogeneities do not significantly affect these vortical-orientation results.

This work is focused on computational modelling of a flow in a burner. The main objective is to provide a complex comparison of the results obtained through several approaches to modeling, on different computational grids and also using different turbulence models. Experimental measurement data are used for validation. Numerically obtained data are compared to each other and to experimental data. The method of Proper-Orthogonal Decomposition is also applied on the calculated data. The greatest benefit of this work is providing a wider view on the swirling flow modeling in burners and the results obtained here will help to better understand the behavior of stated models for tasks of this kind and their potential for modelling combustion in furnaces.

This work investigates flow measurement capabilities within meso- and micro-scaled medically relevant devices using particle image velocimetry (PIV). Medical devices can be particularly challenging to validate due to small length scales and complex geometries, which can reduce measurement accuracy by introducing noise and reducing available signal. Although the sources of such problems are often device specific, the effective outcome is a reduction in the signal-to-noise ratios (SNRs) of PIV images and correlations. This effort utilizes advanced PIV processing and post-processing techniques to establish protocols for achieving high accuracy PIV measurements in challenging flow environments. This investigation takes place within three wide-ranging medically related devices. First, channel flow in a microfluidic device is investigated to evaluate improvements in measurement accuracy gained using phase correlations in comparison to confocal microscopy. This work found substantial improvements in error with respect to the ensemble field for phase correlations while only moderate improvements were observed for confocal imaging with standard processing techniques. Secondly, an evaluation of stenting procedures was executed resulting in the first published PIV and computational fluid dynamics (CFD) joint study on bifurcating stents. This work analyzes steady flow in three bifurcation angles and four different single- and double-stenting procedures, which are clinically used in coronary bifurcations. Finally, a medical device analog was evaluated to develop a comprehensive CFD validation dataset, including a full uncertainty analysis for velocity and wall shear stress as well as estimates for pressure fields and relevant flow statistics including Reynolds stresses and dissipation. / Ph. D.