Impact of Building Configurations on Fluid Flow in an Urban Street Canyon

Abstract

The problem of pollution dispersion in urban areas is significant in the densely populated cities. The topography and barriers in the form of buildings impact the atmospheric fluid flow. The resulting phenomena known as pollution traps cause an artificial dispersion in the buildings’ proximity, affecting the health of ordinary road commuters. The primary source of pollution on the street canyons is exhaust gases from the vehicle movements. However, the concern is associated with the poor dispersion of pollutants under normal wind conditions. The primary reason behind the poor dispersion is the buildings that act as obstacles to the atmospheric wind flow. Thereby it is essential to comprehend the behaviour of pollutants under given shape constraints and flow conditions to improve urban air quality. The present study investigates the wind flow in the proximity of a six-storey building for a medium street canyon configuration under the logarithm inlet velocity profile that acts as atmospheric boundary layer (ABL). Effect of important parameters such as the building height, the wind direction (0, 30, 45, 60, and 90°), and building configurations (straight road, both side building, and only upwind side building with downwind side building) are investigated to gain valuable insights into pollutant dispersion. The analysis of turbulence and velocity profile in the domain at nose level (1.5 m above ground level) leeward sidewalk and windward sidewalk shows turbulent intensity decreases at the nose (breathing) level with building height; however, it increases when the approach angle is 45⁰ suggesting the formation of dominant pockets of pollutants.