Naslov
First observations of the bura wind turbulence using the hot-wire anemometer

Autori
Večenaj, Željko ; Ptičar, Damir ; Hegeduš, Hrvoje ; Lončar, Goran ; Grisogono, Branko

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, ostalo

Izvornik
Knjiga sažetaka - Book of Abstracts / - , 2015

Skup
Meteorological Challenges 4

Mjesto i datum
Zagreb, Hrvatska, 24.11.2015. - 25.11.2015

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
bit će unijeto naknadno

Sažetak
During bura event, i.e., a famous downslope windstorm at the eastern Adriatic coast, difficulties often emerge in traffic, industry and, generally, in everyday life. This is mainly due to bura persistency and severe gustiness (the wind speed maxima may surpass even 70 m/s), which makes bura a subject of intensive scientific research. In the past few decades, statistical, synoptic and main mesoscale characteristics of the bura flow have been comprehensively studied, but some aspects of bura dynamics are still insufficiently investigated, especially its turbulence. The main reason for such situation has been the lack of suitable measurements which are needed to asses these aspects. In this work we address the near-surface bura turbulence. We mounted a single point 1D hot-wire anemometer (HWA) (Dantec Dynamics Multichannel CTA Anemometer System) and 3D ultrasonic anemometer (USA) (Gill Instruments WindMaster) at the north- eastern Adriatic coast in Vratnik Pass (44.98 °N, 14.98 °E, 700 m above MSL) on the mast 2.8 m above the ground. We measured a moderate bura event that occurred on 25 September 2014. We gathered 267 min of data (1451–1918 LST). HWA sampled streamwise wind speed component with sampling rate of 50 kHz while USA sampled all three wind speed components using 10 Hz sampling rate. We performed an in situ calibration of the HWA voltage data using the wind speed data from the collocated USA. In this work we focus on calculation of turbulence kinetic energy dissipation rate, "epsilon". We calculate and compare using the direct dissipation technique and two indirect dissipation techniques: the inertial dissipation technique and the Kolmogorov’s four-fifths law. The goal is to find out which of the two indirect techniques provides better results for bura wind turbulence because the use of indirect techniques significantly reduces expenses needed for the reliable estimation of "epsilon".

Izvorni jezik
Engleski

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