Effects of Street Geometry on Airflow Regimes for Natural Ventilation in Three Different Street Configurations in Enugu City

Efficient natural ventilation is dependent on the micro climate conditions of an urban environment. This is affected by ambient wind flow, radiation and air temperatures. The airflow within the urban street can be cultivated into two regions. The first is a recirculation region, which forms in the near wake of each building. The Second is a ventilated region downstream of the recirculation region, formed when the street is sufficiently wide. The development of the flow into these two regions depends on geometry. This chapter looks at the impacts of street geometry on these regions of airflow cultivation in three different street configurations in high density residential settlements in Enugu city. It utilized schematic analysis of airflow regimes to identify the behaviors of flow in these street configurations relative to the height and width ratios of the street canyon. This schematic analysis can be utilized in preliminary design studies by city and building designers for justifying street dimensions and configurations in tropical regions where natural ventilation is paramount.