Characterization of Near-Surface Turbulent Boundary Layer Flows for Wind Load Analysis and Optimization of Large Frame Structures Under Wind Action
Başlık:
Characterization of Near-Surface Turbulent Boundary Layer Flows for Wind Load Analysis and Optimization of Large Frame Structures Under Wind Action
Yazar:
Caban, Pedro Luis Fernandez, author.
ISBN:
9780438120495
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (154 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 79-11(E), Section: B.
Özet:
This dissertation presents three interrelated studies of importance to the quantification of boundary layer wind loads on civil infrastructure.
The first study refutes the longstanding assumption that near surface wind velocity exhibits Gaussian behavior irrespective of the aerodynamic roughness length of the upwind fetch. Analysis of a large database comprising ground-level anemometric observations during land falling hurricanes, and a series of boundary layer wind tunnel (BLWT) experiments suggest that the longitudinal component of the wind velocity positively skews in more built-up terrain conditions during strong wind events. Quadrant analysis of the Reynolds stress revealed the strong linkage between non-Gaussian observations and sweep events---high-velocity air masses moving towards the surface. The study demonstrates and discusses possible implications of observed non-Gaussian trends on peak loads on buildings.
The second study leverages a comprehensive series of experiments in a large boundary layer wind tunnel to investigate the variation of external pressure coefficients with increasing surface roughness on low-rise buildings. BLWT modeling was carried out on three rigid building models of the Wind Engineering Research Field Laboratory (WERFL) experimental building with geometric scales of 1:20, 1:30, and 1:50. A total of 33 upwind terrain configurations were explored for each model scale. BLWT pressure tests were also compared to aerodynamic experiments of a 1:100 model of the WERFL building conducted at University of Western Ontario (UWO). The findings revealed the dependency of extreme pressure coefficients with increasing surface roughness. Peak pressures near the leading edge of the roof appeared to vary linearly with increasing turbulence levels at eave height. Only slight variations in the mean pressures were observed with increasing turbulence levels.
The third study addresses the optimization of large frame structures subjected to wind action. It presents a new metaheuristic technique to minimize the weight of the structure while satisfying strength and serviceability requirements. The algorithm transitions from the global examination of the design domain, to the restricted investigation around promising regions (subdomains). The latter is performed through a discrete stochastic search scheme, which conducts an exhaustive search near the global optimum during late stages of the optimization process (exploitation).
Notlar:
School code: 0070
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Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(696591.1) | 696591-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
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