Building porosity for better urban ventilation in high-density cities – A computational parametric study

Shape-edged buildings impose large frictional drag on the flow in the urban boundary layer. In the sub-tropics, especially during hot and humid summers, compact building blocks create stagnant air that worsens outdoor urban thermal comfort. The current study adapts the κ–ω SST turbulence model to simulate air flow in urban areas. The accuracy of the κ–ω SST turbulence model in detecting air flow around a rectangular block is validated by comparing it with the data from the wind tunnel experiment. In the computational parametric study, wind speed classification is derived based on Physiological Equivalent Temperature (PET) to evaluate the effect of wind speed on outdoor thermal comfort. Numerical analysis compares the effects of different building morphology modifications on pedestrian-level natural ventilation. Critical design issues are also identified. From both the accuracy and practical points of view, the current study allows city planners and architects to improve building porosity efficiently for better pedestrian-level urban ventilation, without losing land use efficacy.

► The study establishes planning and design methods to improve urban ventilation.
► The methods rely on a parametric study that tests the performance of design options.
► The study applies the κ–ω SST model to simulate turbulence flows in urban areas.
► The study calibrates simulation results using wind tunnel studies.
► The study derives a wind speed classification based on the outdoor thermal comfort.