CFD applications in airship design.

摘要

This thesis examines the aerodynamic characteristics and flight dynamics of a lighter-than-air airship using analytical and computational fluid dynamics (CFD). Modern airships have frequently been proposed for military operations; one of which, designated YEZ-2A, was a prototype whose design was initiated during the 1980's. Designs were evaluated through the wind tunnel tests of a 1:75 scaled model performed by Gomes. His tests relied on surface roughening techniques to compensate for the inability to maintain Reynolds number similarity among scales.;Later, the scaled prototype would receive further attention during a CFD study at WVU. This study was undertaken to numerically simulate the wind tunnel tests of Gomes on the scaled model. Current research was conducted subsequent to these investigations with multiple objectives. Most studies were satisfied by evaluating the prior scaled models in conjunction with full sized CFD models. These evaluations aided in validating the results of all three investigations while exploring potential errors in scaled modeling and turbulent studies. Goals included evaluating previous work through modern numerical analysis. This required a high fidelity CFD modeling approach with appropriate turbulent conditions. Sensitivity studies would ensure credible results independent of the approach. These conditions also served the second goal---providing a modern CFD approach to the design of airships.;This research validated the Gomes' data by means of CFD analysis of 1:75 scale and full scale models of the airship hull. Initial work reexamined the methods developed during the WVU study followed by their implementation for additional analysis. This research included axisymmetric temporal and grid sensitivity studies in addition to 3D analysis. This research confirmed that the techniques Gomes used were incapable of producing accurate full scale flight coefficients. Lastly, this research was presented as a design tool. It demonstrated a modern approach to the design and development of future airships via CFD analysis.