Jet engines operate by ingesting incoming air, adding momentum to it, and exhausting it through a nozzle to produce thrust. Because of their reliance on an inlet stream, jet engines are very sensitive to inlet flow nonuniformities. This makes the study of the effects of inlet nonuniformities essential to improving jet engine performance. Swirl distortion is the presence of flow angle nonuniformity in the inlet stream of a jet engine. Although several attempts have been made to accurately reproduce swirl distortion profiles in a testing environment, there has yet to be a proven method to do so. A new method capable of recreating any arbitrary swirl distortion profile is needed in order to expand the capabilities of inlet distortion testing. This will allow designers to explore how an engine would react to a particular engine airframe combination as well as methods for creating swirl distortion tolerant engines. The following material will present such a method as well as experimental validation of its effectiveness. / Master of Science

Tests were conducted to characterize mixing in a square and a rectangular duct with respect to suitability for single point sampling of contaminants. Several configurations, such as a straight duct with unidirectional flow at the entrance section and straight ducts preceded by mixing elements (a 90° mitred bend, double 90° bends in S- and U-type configurations) were tested. For a straight duct of square cross section, the COV of tracer gas concentration at 19 duct diameters downstream of the gas release location is 143% (Center release). COVs of velocity and tracer gas concentration downstream of each mixing element in square duct setups were verified throughout this study. In the case of a rectangular duct with a 3:1 (width to height) aspect ratio, COVs of velocity and tracer gas concentration only downstream of a 90° mitred bend were verified. Tests were conducted to develop improved inlets for a Battelle bioaerosol sampling system. New inlets have been developed called the All Weather Inlets (AWI), which are designed to prevent entry of precipitation while maintaining aerosol penetration. The AWI has two inlets - one that samples at a flow rate of 780 L/min and the other one that is operated at a flow rate of 90 L/min. The initial version of the AWI-780 L/min unit featured an internal cone, which was removed because the penetration of the AWI-780 without the bottom chamber was higher than that of the Battelle inlet – 81% with the cone while 86% without the cone for around 9.5 µm AD at 2 km/h. The best bug-screen configuration was verified and a cutpoint management process was performed. The inlets were tested with different wind speeds from 2 to 24 km/h to verify the wind sensitivity of those inlets.

This thesis aims to provide a better understanding of the economic and socio-cultural impacts associated with small scale tourism development in the Inuit community of Pond Inlet, Baffin Island. A brief history and economic profile of the community illuminate the reasons underlying its adoption of tourism as a source of income and employment. I then proceed to review past attempts to understand the relationship between tourism and community development. Despite the merits of these studies, they are shown to have largely failed to supply a theoretical framework capable of explaining the underlying factors that influence the scale and nature of the resulting impacts. I then propose that recent theoretical developments, based on the 'flexible specialization' approach, may better assist our attempts to understand the dynamic relationship between tourism and the communities that host it. / The empirical section of the thesis is based on surveys of several key actors: residents, tourists, and the tourist industry. When combined with a simplified multiplier analysis, the findings indicate that the community's current tourism strategy is largely consistent with local economic objectives and that as a result residents support tourism development. Nevertheless, the results suggest certain weaknesses in the current approach to tourism development. They include: the potential for conflicts to develop between local hunters and wildlife watchers; a failure to link tourism to other sectors of the local economy; and difficulties reaching consumers in the context of a restructured travel industry increasingly dominated by computer technology. I then proceed to provide some policy and planning recommendations. This is followed by a brief evaluation of the theoretical approach adopted. I conclude by outlining some areas for future research.

No description available.

Research over the past several decades on the nature of Inuit hunting of narwhals has focused upon harvesting technologies and the traditional ecological knowledge of modern hunting of the species. However, as much as such work has contributed to our understanding of Inuit and narwhal interaction, less is known about contemporary Inuit hunting behaviour of narwhal. The research presented in this dissertation redresses this gap by providing a detailed behavioural description and analysis of the Inuit narwhal hunting in two critical environments utilized by the Inuit of Pond Inlet---those of the spring floe-edge and the summer open water. / This information and its analysis are presented through three manuscripts. The first manuscript forms the analytical basis of the behavioural description by presenting through the use of a decision flow chart, the parameters that affect narwhal hunting. The second and third manuscript explore different foraging strategies involved in several major decisions the Inuit typically face when pursuing narwhal at the floe-edge (Manuscript Two) and in the open water environment (Manuscript Three). The data pertinent to the major decision factors influencing actions in both environments were obtained through participant observation, supplemented by interviews with hunters and elders. / The main results of this research pertain to the different, but complementary, strategies employed by Mittimatalingmiut (Pond Inlet Inuit) hunters during the floe-edge and ice free seasons, as well as during the transition between the two. Before break-up, the most frequent method employed in floe-edge and outpost camp hunts is an ambush or a sit-and-wait strategy. Interestingly, during the transition between floe-edge and complete open water, Pond Inlet Inuit utilized both sit-and-wait and pursuit hunting strategies to maximize their hunting opportunities.

No description available.

The interior flowfield analysis of fan has been considered to be one of the most difficult problems in the past. With the advent of computational fluid dynamics (CFD) methods, many flow problems inside the fan can now be solved with a good degree of accuracy. ¡@ A numerical study of the influence of inlet cone and volute cutoff on a centrifugal fan performance is presented in this work. Using the flow-visualization simulating analysis of the flow-flied characteristic of air across the inner of centrifugal fan, the performance curve with different inlet cone shape, inlet clearance gap, cone position, extending angle and curvature radius of cutoff arc were obtained and explored. The Reynolds-Averaged Navier- Stokes equations with the Standard k-£` turbulence model is used to simulate the three-dimensional, steady, incompressible, turbulent flow field inside a double-suction backward-curved centrifugal fan and is solved by control volume method. The numerical model is validated by experimental data. The results showed that (i) the inlet cone can induce the air to enter into the impeller smoothly and uniformly, which reduces the flow-separation occurrence along the blade surface. However, the inlet cone with larger friction loss will also slightly lessen the fan performance; (ii) recirculation zones appear inside the volute channel due to the existence of inlet clearance gap between inlet cone and volute, which results in part of fluid leaving from the impeller outlet re-entering into the impeller inlet and reducing the fan performance. This recirculation leakage ratio of fluid through inlet clearance gap increases with increasing inlet clearance gap, which is also depends on the shape of inlet cone; (ii) the distance of inlet cone extending into the impeller will interfere the uniformity of inlet airflow distribution along each blade height. The longer the extending distance, the larger the vortex zone occupying the inter-blade space which makes less fan performance; (iv) it makes only little improvement in the fan performance to change the shape of volute cutoff. ¡@ It is found that (1) decreasing the inlet clearance from 11mm to 5mm, the outlet average total pressure increases about 3.26%; (2) increasing the distance of inlet cone extending into the impeller from 0mm from 20mm, the outlet average total pressure decreases about 6.32%; (3)changing the shape of inlet cone, the outlet average total pressure increases up to 5.4%, and (4) reducing the tongue radius of volute cutoff from 25mm to 15mm, the performance efficiency of fan promotes slightly about 1%.

Analysis of monthly observations of temperature, salinity and dissolved oxygen content in the basin formed by Rupert and Holberg Inlets reveals a greater degree of mixing than that found in most British Columbia Inlets. Although relatively uniform water properties are constantly found, there are large monthly variations of the actual values. The water temperature correlates with the solar radiation while the salinity changes follow the river runoff which is in turn controlled by precipitation. The variation in dissolved oxygen content appears due to a combination of biological influences and influx of Pacific Oceanic water. A model has been developed which ascribes the monthly fluctuations and vertical homogeneity to an accumulation of irregular mixing events associated with the tidal flow through Quatsino Narrows, a shallow connecting channel. Thermal microstructure measurements disclose a region of deep turbulent mixing near the narrows and provide evidence of an up-inlet flow beneath the thermocline in Rupert and Holberg Inlets. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Computational investigations were carried out on an advanced serpentine jet engine inlet duct to understand the development and propagation of secondary flow structures. Computational analysis which went in tandem with experimental investigation was required to aid secondary flow control required for enhanced pressure recovery and decreased distortion at the engine face. In the wake of earlier attempts with modular fluidic actuators used for this study, efforts were directed towards optimizing the actuator configurations. Backed by both computational and experimental resources, many variations in the interaction of fluidic actuators with the mainstream flow were attempted in the hope of best controlling secondary flow formation. Over the length of the studies, better understanding of the flow physics governing flow control for 3D curved ducts was developed. Blowing tangentially, to the wall at the bends of the S-duct, proved extremely effective in enforcing active flow control. At practical jet momentum coefficients, significant improvements characterized by an improved pressure recove ry of 37% and a decrease in distortion close to 90% were seen.

The specific power (or specific thrust) of modern gas turbines is much influenced by the gas temperature at turbine inlet. Even with the use of the best superalloy available and the most advanced cooling configurations, there are competitive pressures to operate engines at even higher gas temperatures. Ceramic coatings operate as thermal barriers and can allow the gas temperature to be increased by 50 to 220 K over the operating gas temperature for an uncoated turbine . It is important that the surface temperature of the blade be determined as accurately as possible. Large uncertainties as to the surface temperature require significant margins for safe operation . Blade surface temperatures can be determined with an accuracy of 10 K using radiation pyrometry and about'30 to 40 K by calculating the blade temperature based on---gas temperature measurement of the exhaust gas plane. This'- makes pyrometry an attractive option for advanced high temperature gas turbines . However, there is little experience in measuring surface temperatures of blades coated with ceramic coatings. There is evidence that the. radiation signal picked up by the pyrometer will not only depend on the surface temperature but also on a number of optical properties of the coating. Important among these are the emissivity of the coating and whether the coating is translucent. Parameters affecting this are the coating material, coating surface finish, coating thickness and whether or not a bond coat is used . This work explores these variables in a rig that simulates the conditions within a turbine stage of a gas turbine engine. In which six thermal barrier coating systems were tested. These systems are of current interest to gas turbine manufacturers and users. They include the latest advances in coating technology. Four stabilized zirconia systems and two alumina based systems were tested. It was found experimentally that the surface emissivity of these coating systems was invariant over the range 873 to 1023 K surface temperature. It was found that the use of different stabilizers did not affect the surface spectral emissivity. In further experiments six turbine wheels were coated with these systems and tested at turbine entry temperatures of 973, 1073, and 1173 K. It was found that the blade surface temperature was function of the coating material, coating thickness and turbine entry temperature. The blade surface temperature was also function of the blade height being maximum at the blade tip and minimum at the blade root . It was found that the C-YPSZ was better insulator than the rest of the systems. Whilst the blades coated with zirconia based systems suffered minor loss near the edges, the two alumina based systems were lost from more than a blade during the test. This coating loss was picked up by. the pyrometer . Analysis shows that the measured blade surface temperature was within 10 K of that calculated. The use of 0.3 mm of C-YPSZ on air cooled turbine blades caused 250 K surface temperature increase and 270 K metal temperature decrease for turbine entry temperature of 1673 K. The metal temperature reduction was as high as 310 K for coating thickness of 0.5 mm.