Dynamic evolutions of traffic wind influenced by ambient wind for urban road tunnel with shafts

Abstract

Urban road tunnels with shafts have been applied in some cities in China. Field measurements of Mofan Road Tunnel show that ambient wind is widespread and its influence on the ventilation efficiency of shaft is unclear. In this paper, the physical model of a three-lane 210 m (length) *12 m (width) *6 m (height) tunnel is studied, with three vehicles in each lane and a speed of 60 km/h. Three-dimensional CFD simulations on a 210 m long tunnel with double shafts is carried out by Fluent 6.3.26. Momentum equation and k-ε equation turbulence model are used for simulation analysis and dynamic grid technology is used to simulate vehicles driving. It is found that the ambient wind in tunnel has great influence on the flow field in tunnel and shaft. Number Ri is defined as the ratio of horizontal inertia force to vertical inertia force, revealing the conversion of horizontal inertia force to vertical inertia force.

Keywords

• urban road tunnel with shafts
• ambient wind
• traffic wind
• dynamic grid
• ventilation efficiency