Numerical Investigation of the Impact of Tall Buildings on Pollutant Dispersion during Stable Stratification

Abstract

The present study employs the k-epsilon turbulence model to investigate the influence of stable stratification with different Richardson numbers (Rib) on flow patterns and pollutant dispersion near tall buildings. The results show that thermal stratification significantly affects the flow pattern around buildings. As Rib increases, the leeward stagnation point gradually shifts upward toward the top of the building, while the recirculation region on the top of the building moves downward, and the length of the recirculation region on the windward side initially increases and then decreases. The vortex position gradually moves above the building. The region with high TKE/uH2 is primarily concentrated on the top of the building and within the downwind recirculation area. As Rib increases, the TKE/uH2 decreases in the top and wake regions of the building. With increasing Rib, the ground-level pollutant concentration first increases and then decreases, the height of the downwind plume gradually reduces, while the maximum concentration in the plume rises.

Keywords

• stable stratification
• numerical investigation
• tall buildings
• dispersion