engleski

Bura turbulence in comparison with international wind engineering standards

Bura is a strong, gusty, temporally and spatially variable downslope wind. Bura mean velocity is not that significant, but its strong gusts create significant problems to traffic and engineering structures. Therefore, further research is required to fully elucidate bura turbulence in a form usable for engineers. In this study, unique high-frequency measurements, carried out on a meteorological tower in the hinterland of the city of Split, Croatia are analyzed. Time histories and vertical profiles are analyzed for turbulence intensity, Reynolds shear stress and turbulence length scales in comparison with recommendations provided in major international wind engineering standards. For mean wind velocities larger than 5 m/s, turbulence intensity and Reynolds shear stress are noticed to remain within the same range of values during the observed bura episode. Turbulence intensity and absolute Reynolds shear stress decrease with increasing height from the ground, while simultaneously turbulence length scales increase, all in accordance with the atmospheric physics. For the respective terrain type, the obtained vertical profiles of turbulence intensity, Reynolds shear stress and longitudinal turbulence length scales agree well with international standards. On the other hand, turbulence length scales related to lateral and vertical velocity fluctuations are considerably larger than the standard values that may have significant implications with respect to bura loads on engineering structures and vehicles.

Logaritmic law ; Power law ; Turbulence intensity ; Reynolds shear sress ; Turbulence length scales

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