Ventilation Effect and Optimum Design of an Urban I-Shaped Pedestrian Underpass

Abstract

To reveal the reason for moisture condensation of an I-shaped pedestrian underpass in the summer, which is widely constructed in many large southern cities of China, its ventilation effect was investigated under a hot, rainy, and humid climate condition. Through in situ monitoring of the Yuejiazui I-shaped pedestrian underpass in Wuhan City, China, some internal environment parameters, such as the wind speed, relative humidity, air temperature, and wall temperature, were recorded and analyzed systematically. Then, with computational fluid dynamics (CFD), numerical simulation studies were conducted by comparing the field measured data. The results show that the main tunnel of the I-shaped underpass cannot achieve effective natural ventilation, and the underpass is often in a higher humidity state in the summer; therefore, it is prone to serious moisture condensation. Meanwhile, the Magnus formula was used to investigate the cause of moisture condensation. To improve the ventilation effect of the underpass, different optimization models were compared by CFD numerical simulations to further validate the rationality of the optimization scheme. The results can provide references for the design of urban pedestrian underpasses in hot-moist climate regions.