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Correlated wind turbulence and aeroelastic instability modeling for 3-D time-domain analysis of slender structural systems

Posted on:2008-12-12Degree:Ph.DType:Dissertation
University:Colorado State UniversityCandidate:Goode, Jonathan SFull Text:PDF
GTID:1442390005972395Subject:Engineering
Abstract/Summary:
Slender structural systems, such as high-mast lighting structural supports, are known to be sensitive to natural wind fluctuations. In particular, these systems are also prone to produce aeroelastic instabilities as a result of the structural motion and wind flow. This in turn can result in poor fatigue performance for these structures. In order to accurately estimate this fatigue performance, numerical time-domain solution techniques are needed. Time-domain solutions, however, require accurate modeling of the fluid/structure interaction and the structural system. Because these systems interact with the wind flow, this modeling problem is only exacerbated due to the modeling complexities associated with the wind flow and corresponding aeroelastic instabilities. This study seeks to incorporate existing models for wind flow and vortex shedding into a numerical time-domain analysis solution procedure.;The objectives and contributions of this study are focused on three modeling techniques. First, the modeling of the approach wind flows to generate a simulated wind speed time history for use in the time-domain structural analysis algorithm is considered. The approach makes use of random field theory to model the spatial correlation of the approach flow based on an empirical relationship. The effects of varying the spatial correlation of the wind flow on the response of the slender structural system are determined. Second, the modeling of vortex shedding phenomenon into the time-domain structural analysis routine is implemented. Again, the model considered is empirical in nature and a numerical investigation is similarly conducted to determine the effects of varying parameters of the model on the response of the structure. Finally, the fatigue performance of a structural system with respect to a statistically described lifetime wind speed distribution that describes the natural wind fluctuations over the lifetime of the structure is modeled. The spatially correlated wind flow and vortex shedding models are subsequently included to determine their effects on the fatigue performance of the system. Recommendations for future study and improvement are made so that other studies can extend the work contained herein to obtain further understanding and potential improvements in design standards and mitigation techniques to improve performance.
Keywords/Search Tags:Wind, Structural, Modeling, Time-domain, Performance, Aeroelastic
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