Ph.D. Tezi Görüntüleme | |||||||||||||||||||||
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| Summary: In this study, flow fields around roof models, which are in different types and slopes have been investigated experimentally and theoretically in order to search the wind loads that can damage the buildings. The experimental part of the study was carried out in an atmospheric boundary layer that is modeled in the wind tunnel. Atmospheric boundary layer was simulated with combination of barrier, elliptic vortex generators and elements of roughness and at 15 m/s wind velocity, a 150 mm height boundary layer is formed and flow visualization, velocity and surface pressure measurements are done at the flow fields around building models which have four different roof slopes as 0º, 15º, 30º and 45º. For flow visualization oil and paraffin vapour techniques were used. Then, mean velocity and turbulence components on the roof models were measured with hot-wire anemometry system. The correlation between atmospheric turbulence and wind-induced turbulence was investigated and a correlation was obtained around % 50 level except for reverse flow region. For various roof geometries, eaves types and wind direction the mean and fluctuating surface pressures were measured in more detail. According to mean and fluctuating surface pressure measurements on the roof models, the critical roof slope and wind direction were found as 15º and 45º respectively. It is observed that, the spoiler elements placed at the critical negative peak pressure regions on the models have decreased suction effect on those regions up to % 50 level.In the theoretical part of the study, 2D numerical solutions in flow fields were obtained using FLUENT commercial package. In the numerical studies, the performances of turbulence models were evaluated and when compared with experimental data, it was seen that Realizable k-epsilon at the prediction of velocity fields and Standard k-omega model at the prediction of surface pressures have more precise results. Key Words: Atmospheric Boundary Layer, Flow Separation, Roofs, Eaves, Suction Loads, Pressure Coefficient, Turbulence Model | |||||||||||||||||||||