http://smartech.gatech.edu/handle/1853/16122 Research Thesis Option for Aerospace Engineering Majors. Search the Channel search http://smartech.gatech.edu/simple-search http://smartech.gatech.edu/handle/1853/19948 Title: Image Analysis of Acoustically Excited Bluff Body Flames <br/> <br/>Authors: Plaks, Dmitriy Vital <br/> <br/>Abstract: This thesis analyzes the effects of various bluff bodies on the downstream flow field. Bluff bodies, for example, those typically found in jet engine augmentors, are objects designed to impede the flow in order to stabilize a flame. The effects of different bluff body shapes (cylindrical and triangular), size (6.35 mm, 9.53 mm, 12.7 mm, and 19.1 mm) and heat release are examined with respect to their influence on downstream vorticity strength, vortex separation distance, and vorticity divergence angle. Particle Image Velocimetry (PIV) is used to obtain the velocity field data from which the vorticity field is calculated. The mean flow velocity, U∞ is 2.7 m/s, and the flow is acoustically excited at 300 Hz with a normalized acoustic velocity of u'/U∞ = 0.8. The vorticity divergence angle increases with increasing bluff body size, is not affected by bluff body shape, and has a non-linear correlation with heat release. Downstream vorticity strength is affected by all three parameters (bluff body shape, size and heat release) in a non-linear manner. Vortex separation distance is a function primarily of bluff body size, increasing for larger bodies; however, the separation distance decreases with increasing heat release. Bluff body shape also has an effect on vortex separation distance as the cylindrical bluff body creates a larger separation distance between vortices. http://smartech.gatech.edu/handle/1853/16119 Title: Non-Deterministic Design of Utility Scale Wind Energy Systems <br/> <br/>Authors: Scott, Robert <br/> <br/>Abstract: The wind is an increasingly significant source of energy with the rising price of non-renewable fuels. The purpose of this project is to determine the specific intensity and frequency of wind speed required to sustain a large-scale wind farm with power output on the order of hundreds of megawatts. To this end, a non-deterministic methodology will be developed to analyze the viability of wind energy systems. A deterministic analysis method considers the majority of design parameters to be known or fixed and may only perform trade studies on a few parameters at a time to optimize performance. In the case of the energy market though, this is not an advantageous strategy since several factors related to economic viability such as energy prices, interest rates, government incentives, acquisition costs and maintenance are highly variable and cannot be assumed to be known. A non-deterministic, statistical approach to wind turbine design has the advantage of predicting with corresponding levels of certainty the power output and economic viability of an energy system. The primary goal of this project is to define the envelope of operating conditions for a large-scale wind project while considering variables of both engineering and economic significance. The National Renewable Energy Laboratory’s (NREL) Hybrid Optimization Model for Electric Renewables (HOMER) will be incorporated into the previous analysis using YawDyn and PROPID to determine the economic returns on investment in hypothetical financing cases. Cost factors will now be assigned a mean value along with a probability distribution. Monte Carlo simulations will be run for a large number of variations in the assumed economic and engineering variables to develop an accurate estimate of the price per kilowatt-hour of energy produced from the simulated wind project for a variety of site conditions with the goal of finding the most suitable environment for sustainable wind development. http://smartech.gatech.edu/handle/1853/16111 Title: Direct Conversion for Space Solar Power <br/> <br/>Authors: Boechler, Nicholas Sebastian <br/> <br/>Abstract: Space Solar Power (SSP) is a powerful yet nearly untapped resource with revolutionary potential. SSP systems currently have several roadblocks to their implementation. With the technology in use today, converting solar power to useable energy is inefficient, the required converters have a large mass per unit power, and launching those converters is expensive. More fundamentally, in all current SSP systems, energy is generated in the form of a direct current before being converted again into whatever form is necessary. In addition to the large mass per unit energy of this conversion equipment, such conversion involves significant efficiency losses, further resulting in the prohibitive cost of launching these converters into space. If techniques could be discovered for converting broadband sunlight directly to a useable narrowband application dependent frequency, many fundamental breakthroughs in aerospace endeavors can be achieved. This project studied a large number of options that might lead to direct conversion. Those technology options were analyzed according to which would warrant further exploration from the point of view of aerospace systems applications and possible power per unit mass. Based on these technologies, several advanced concepts were considered. It is also important to make an estimate of the possible power per unit mass that could be achieved with each concept, so that architecture developers can proceed with the development of applications enabled by direct conversion technology. Accordingly, estimates of the possible power per unit mass of potential direct conversion systems were made, and future applications that would benefit from those direct conversion systems were identified. Three possible concepts were developed. These concepts include: a shocked photonic crystal system; a solar pumped maser based on naturally occurring astronomical masers; and an optical antenna array with central signal processing. The optical antenna array and the solar pumped maser were estimated to have a specific power approximately 15.0 and 10.8 times greater, respectively, than conventional photovoltaic systems. Additionally, several applications were identified that would benefit from direct conversion systems, including a SSP grid and electric propulsion.