Influence of Traffic Flow Characteristics on Traffic Wind of Highway Tunnel

In ventilation of highway tunnel, the traffic wind generated by moving vehicles causes air flowing. Traffic flow makes an essential effect on the traffic wind. In this paper, we studied the relationships between traffic wind and traffic flow factors separately, including traffic speed and vehicle proportion. A computational simulation using dynamic mesh was carried out. Three types of vehicles, sedan, minibus, and coach, were consisted in the traffic flow. Meanwhile, based on different average speeds, the traffic flow were defined as three scenarios: free flow, mild jam, and moderate jam. According to the simulation results of three-lane tunnel, traffic wind in tunnel was influenced by the sedan proportion and average speed significantly. In three traffic scenarios, the average wind speed increased as the proportion of sedan decreased. As the proportion of sedan reduced from 100% to 50%, the average traffic wind speed in the tunnel reached nearly 1.5 times. Furthermore, when the proportion of sedan was fixed, the increase of the average speed could lead the average wind speed increasing, too. It can be concluded that traffic wind as a kind of natural resource, affords an important supplement to the tunnel ventilation system, thereby reduces the electricity cost of tunnel operation.