Numerical Simulation Of Air Pollution In An Urban Community Of City Underlying Surface With WRF-CMAQ-CFD Multi-scale Coupled Method

Because of China’s 30 years of sustained economy growth, people’s living standard has been greatly improved, and more and more people have moved from country to city. Although the rapid growth of urbanization can increase resource utilization efficiency, the rapid expansion of the urban population also leads to a lot of problems, such as traffic congestion, noise pollution, air pollution, water pollution, soil contamination and so on. This study explores the method of coupling CFD with mesoscale software WRF, CMAQ to simulate city’s environment.This paper introduces geographical and climatic conditions of the region, and then constructs the simulation model by simplifying unrelated buildings. We use Gambit to mesh the entire domain, which leads to about 14 million tetrahedronal cell. When comparing the simulation results to the monitoring results, CFD method is more accurate than the CMAQ method in most of the time. Therefore we conclude that CFD method is a better simulation method.This paper also considers the impact of vehicle pollution to its surrounding environment. We takes the impact of motor vehicle exhausts and chemical reaction mechanism of pollutants into count when we simulate the urban environment. We also conduct qualitative and quantitative analysis of the characteristics of vertical and horizontal transmission of the pollutants. In the end, we also study the different wind and pollutant environment characteristics in different seasons, hoping to gain more knowledge of pollutant transportation in urban environment.