Bora wind characteristics for engineering applications

Lepri, Petra and Večenaj, Željko and Kozmar, Hrvoje and Grisogono, Branko (2017) Bora wind characteristics for engineering applications. = Bora wind characteristics for engineering applications. Wind and structures, 24 (6). pp. 579-611. ISSN 1226-6116. Vrsta rada: ["eprint_fieldopt_article_type_article" not defined]. Kvartili JCR: Q3 (2016). Točan broj autora: 4.

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Bora is a strong, usually dry temporally and spatially transient wind that is common at the eastern Adriatic Coast and many other dynamically similar regions around the world. One of the Bora main characteristics is its gustiness, when wind velocities can reach up to five times the mean velocity. Bora often creates significant problems to traffic, structures and human life in general. In this study, Bora velocity and near-ground turbulence are studied using the results of three- level high-frequency Bora field measurements carried out on a meteorological tower near the city of Split, Croatia. These measurements are analyzed for a period from April 2010 until June 2011. This rather long period allows for making quite robust and reliable conclusions. The focus is on mean Bora velocity, turbulence intensity, Reynolds shear stress and turbulence length scale profiles, as well as on Bora velocity power spectra and thermal stratification. The results are compared with commonly used empirical laws and recommendations provided in the ESDU 85020 wind engineering standard to question its applicability to Bora. The obtained results report some interesting findings. In particular, the empirical power- and logarithmic laws proved to fit mean Bora velocity profiles well. With decreasing Bora velocity there is an increase in the power-law exponent and aerodynamic surface roughness length, and simultaneously a decrease in friction velocity. This indicates an urban-like velocity profile for smaller wind velocities and a rural- like velocity profile for larger wind velocities. Bora proved to be near-neutral thermally stratified. Turbulence intensity and lateral component of turbulence length scales agree well with ESDU 85020 for this particular terrain type. Longitudinal and vertical turbulence length scales, Reynolds shear stress and velocity power spectra differ considerably from ESDU 85020. This may have significant implications on calculations of Bora wind loads on structures.

Item Type: Article (["eprint_fieldopt_article_type_article" not defined])
Keywords (Croatian): ora wind ; gusts ; velocity profile ; thermal stratification ; turbulence intensity ; Reynolds shear stress ; turbulence length scales ; velocity power spectra ; field measurements
Subjects: TECHNICAL SCIENCE > Mechanical Engineering
Divisions: 1400 Department of fluid mechanics > 1420 Chair of environment and construction aerodynamics
Indexed in Web of Science: Yes
Indexed in Current Contents: Yes
Quartiles: Q3 (2016)
Date Deposited: 28 Aug 2017 07:29
Last Modified: 28 Aug 2017 07:29

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