Pedestrian-Level Wind Speed Enhancement with Void Decks in Realistic Built Environments

Building voids at the pedestrian level allows wind to flow through them, thereby reducing the resistance to pedestrian-level wind speed. Previous studies show that pedestrian-level wind speed can be significantly enhanced with void decks in the form of empty ground floor (also known as “lift-up buildings” in some studies) in idealized urban street canyons. This study explores the wind-enhancement potential of void decks in realistic built environments. Computational fluid dynamics (CFD) simulations are used to simulate the wind fields of two residential sites in Singapore. The first site has simple building geometry and smooth (unobstructed) upwind areas, while the second site has complex building geometry and rough upwind areas. For each site, the simulated wind fields with and without void decks are compared to extract the effects of void decks. For the first site, the wind enhancement effects are significant, reaching up to 80% of the atmospheric wind speed. However, for the second site, the wind enhancement effects are only up to 50% of the atmospheric wind speed due to the rough upwind conditions. The CFD results also show that some areas suffer from wind speed reduction, but overall, void decks have a net positive effect to enhance pedestrian-level wind speed, especially with smooth upwind conditions. Therefore, void decks are an effective architectural features to passively improve urban ventilation, which promotes heat and pollutant dispersion.