CFD Analysis of the Impact of Building Layout and Morphology on Pedestrian-Level Airflow and Pollutant Stagnation in Urban Areas with Well-Developed Surface Boundary Layers

This study focuses on the features of wind flow and pollutant diffusion of continuous urban street canyons with distinct surface boundary layers through computational fluid dynamics (CFD) analysis. The CFD analysis is set as cyclic boundary conditions to represent the continuous canyons. This study establishes four cases with different building heights and arrangements, and three cases with different atmospheric stability conditions to evaluate the effects of building types and atmospheric stability on wind flow and ventilation characteristics. Pollutants were emitted in a section below the height of 7.5 m from the ground to figure out the ventilation performance of spaces where pedestrians move within urban street canyons. Ventilation rate and purging flow rate (PFR) were calculated to confirm the results. Furthermore, this study analyzed the effects of the ventilation efficiency of canyons on ventilation performance depending on canyon patterns and diverse conditions of atmospheric stability.