Model vehicle movement system in wind tunnels for exhaust dispersion studies under various urban street configurations

The exhaust dispersion in the close vicinity of urban roadways and intersections takes place under the joint influence of natural and vehicle-induced turbulence. The physical simulation studies of vehicular exhaust using wind tunnels have shown high potential to understand complex dispersion mechanisms. One of the vital components of simulation in the environmental wind tunnel (EWT) is the design of model vehicle movement system (MVMS). An efficient design of MVMS is a foremost requirement for carrying out exhaust dispersion studies in the EWT, otherwise it may adversely affect the atmospheric boundary layer. Therefore, an attempt has been made to critically review the previously used MVMS in exhaust dispersion studies. Further, sophisticated MVMS with real traffic situation for urban streets at various configurations has been designed and developed. The MVMS for urban streets and intersection has been successfully operated for variable traffic volume and speed as seen in real life situation. In addition, multi-lane traffic for two-way urban roads has also been successfully operated. The dispersion results revealed that the traffic induced turbulence at low wind condition causes considerable amount of pollutant reduction in urban street canyon surrounded by high-rise buildings.