engleski

Natural ventilation of the Sv. Rok Tunnel

The natural road tunnel ventilation was studied on the example of the Sveti Rok Tunnel (5670 m long) that connect continental (continental climate) and coastal (Maritime climate) part of Croatia. The purpose of the analysis was to obtain information as needed for the design of proper tunnel ventilation system. The natural tunnel ventilation exists when the pressure difference between the tunnel portals is big enough to compensate forces that are consequence of longitudinal tunnel inclination and flow resistances. The analysis is based on the meteorological measurements that took place from February 1999 to August 2003 on the both tunnel portals. Air pressure differences between the portals are in 46.5% cases grater than 1 hPa. In 80% of all measurement terms the air density difference between the portals are positive (air flows from continental to the costal entrance of the tunnel). The most favorable weather situations for the natural tunnel ventilation are those with relatively week winds and very pronounced temperature difference with stationary cold air mass on the northern slopes of Velebit mountain.

Tunnel ventilation; pressure difference; wind

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