The three-dimensional lid-driven cavity flow is investigated at Reynolds Number(Re)=10,000 for a wide range of spanwise-aspect ratios of 3:1:1, 0.5:1:1, and 1:1:1 using the Partially Averaged Navier-Stokes(PANS) turbulence closure model. The PANS turbulence model is a variable resolution turbulence closure model, where the unresolved-to-total ratios of kinetic energy (fk) and dissipation (fe), serve as resolution control parameters. This study focuses on two main aspects of PANS: (i) the evaluation of Turbulent transport models and (ii) the effect of grid spacing on accuracy of the numerical solution. PANS calculations are tested against LES and experimental results of Jordan (1994), in terms of both qualitative and quantitative quantities. The main coclusions are are: (i) for a given fk value, the Zero-Transport model is superior to the Maximum-Transport model for unresolved dissipation, (ii) both models are adequate for unresolved kinetic energy, and (iii) for a given grid size, the results depend heavily on grid spacing especially for larger fk values.

Short cavity lasers have several advantages such as improved output linearity in comparison with long lasers, longitudinal oscillation mode stabilized against the injection level and the operating temperature, and large mode spacing for allowing single-mode operation. In this paper, a short cavity laser has been successfully fabricated. The waveguides of laser diodes were formed by wet-etching with width of 4£gm. A SiO2 thin film was then sputtered onto the sample as surface passivation layer, after that, a PMGI polymer was spun on the sample and used for opening ridge window of metalization. After the SiO2 layers on the top of the ridge were removed, the metalizations were deposited for contact. The final finished laser was 200£gm long. The turn on voltage of the laser diode is 0.8 V with total resistance of 9.8£[. In the CW operation, the threshold current of laser is 20mA with threshold voltage of 1.3V, reaching total output optical power of 8mW at 50mA and 12mW at 70mA. The small signal frequency response is 8GHz (current 70mA). By adopting fiber grating and circulator to filter the main mode, the side mode suppression ratio (SMSR) of single longitudinal mode is about 40dB, showing single mode operation.

The three-dimensional lid-driven cavity flow is investigated at Reynolds Number(Re)=10,000 for a wide range of spanwise-aspect ratios of 3:1:1, 0.5:1:1, and 1:1:1 using the Partially Averaged Navier-Stokes(PANS) turbulence closure model. The PANS turbulence model is a variable resolution turbulence closure model, where the unresolved-to-total ratios of kinetic energy (fk) and dissipation (fe), serve as resolution control parameters. This study focuses on two main aspects of PANS: (i) the evaluation of Turbulent transport models and (ii) the effect of grid spacing on accuracy of the numerical solution. PANS calculations are tested against LES and experimental results of Jordan (1994), in terms of both qualitative and quantitative quantities. The main coclusions are are: (i) for a given fk value, the Zero-Transport model is superior to the Maximum-Transport model for unresolved dissipation, (ii) both models are adequate for unresolved kinetic energy, and (iii) for a given grid size, the results depend heavily on grid spacing especially for larger fk values.

Thesis (M.Sc.(Odontology))--University of Pretoria, 2009. / Includes bibliographical references.

The goal of the thesis was to change reduce the noise produced from a small cavity with grazing sub sonic flow, via alterations in geometry. Research was done into how noise was produced in cavities and existing research in the field. While most work had been done in super sonic flow, little had been done for small cavities at slow, automobile level speeds. Despite the small amount of work done, several features of geometry were noted as affecting the production of sound in cavities. Several of these were chosen to be tested. A modular test rig was designed to allow easy change between the various geometries being tested. It had a flat top surface (of which the cavity came off) to keep the experiment generic, while the bottom surface was a combination of two slopes to keep disturbance to the flow at a minimum and reduce the background noise. A new working section, contraction and anechoic termination were designed and produced to add onto the existing wind tunnel in the mechanical engineering wing at the University of Canterbury. The noise production from a cavity is dependent upon the interaction between the vortices travelling in a 'shear layer' over the cavity throat interact with the front and rear edge of the cavity throat. By minimising the impact to the vortices as they travel between cavity edges, significant noise attenuation can occur. The most successful strategies were lowering the rear edge relative to the front edge and putting ramps on the front and rear edges. To test the principle of superposition, these two strategies, along with an 'L' plate (the third best strategy) were put together to make a 'Super' cavity. the noise spectrum from this cavity was almost identical to the background noise. Removal of the 'L' plate improved sound attenuation even more. Work to do in the future includes testing more examples of each geometry modification, as time constraints minimised the variations on each modification tested. Additionally, the super cavity should be tested in a curved, aerofoil/roof rack extrusion, to see if it as effective in a curved environment as a flat one. All experimental work was done at 100km/h, to coincide with the open road speed limit in New Zealand. The tests should be redone at different speeds, so a more complete picture of the cavity noise can be produced.

Thesis (M.S.)--Oregon State University, 1997. / Typescript (photocopy). Includes bibliographical references (leaves 92-96). Also available on the World Wide Web.

Thesis (M.S.)--University of Michigan, Ann Arbor, 1976. / Typescript (photocopy). Includes bibliographical references (leaves 25-28). Also issued in print.

Thesis (M.S.)--University of Michigan, Ann Arbor, 1972. / Typescript (photocopy). Includes bibliographical references (leave 21). Also issued in print.

Thesis (M.S.)--University of Michigan, Ann Arbor, 1972. / Typescript (photocopy). Includes bibliographical references (leaves 11-12). Also issued in print.

Thesis (M.S.)--University of Michigan, 1986.