Pressure and velocity distribution in the new tube of the Plabutschtunnel

The main ridge of the Alps lays just crosses Austria. Therefore it is not surprising that most highways in Austria do have to pass through a lot of road tunnels. Among these tunnels, some of the world longest tunnels for vehicle traffic are found. For safety reasons today all long road tunnels are planed with two tubes. Two tubes allow one way traffic in each tube. In the case of one way traffic it is easier to deal with the dense smoke which can be produced by heavy fires. However due do the very high cost in many cases only one tube was finished first and therefore the tunnel has to be operated with two-way traffic. After some years the second tube was opened and the traffic was changed to one-way traffic. The layout of the ventilation system must be a way, so that both cases -one way traffic and two way trafficcan be handled in normal operation and in fire situations. The authors developed system to model the ventilation system in normal operation and in fire situations. The model is used for two different situations. On the one hand the necessary regulations for the ventilation system under normal conditions are calculated, on the other and simulations can be done to foresee the influence of many changes of traffic conditions or changes in the ventilation system. For many cases the velocities in all ducts of the tunnel and the pressure distribution can be calculated. Key-words: road tunnel, ventilation, piston effect, one-way – two-way traffic Proceedings of the 5th IASME / WSEAS International Conference on Fluid Mechanics and Aerodynamics, Athens, Greece, August 25-27, 2007 307