Modeling of Atmospheric Turbulent Boundary Layer and Dispersion of Small Scale Solid Pollutants in an Urban Area Using Large Eddy Simulation

Abstract

One of the important factors about the metropolitan air quality is the wind blowing in that environment so that if no wind with effective power for a long time in the metropolitan, the phenomenon of air stagnation occurs and as a result, the concentration of the pollutants will lead to critical conditions. With the wind, these pollutants are scattered throughout the environment. The distribution of these particles depends on factors such as wind velocity, ambient geometry and physical properties of the contaminants and predicting their dispersal and settlement in a small urban environment requires accurate, high-resolution modeling. In the first part of this research a simple model including a building, simulated and results of this modeling including wind flow and velocity field around the building, are compared and validated with experimental results obtained by wind tunnel tests. By identifying the optimal parameters in the modeling settings in the first part, In the following and in the second part, an area of Tehran city with high-rise buildings and irregular urban layout is considered and the velocity field and the dispersion and deposition of the contaminant particles in this real sample environment are also simulated. The results of the study including the variation of the concentration of pollutants at different surfaces over time presented and the factors affecting the concentration of the pollutants are discussed.