Abstract
High-density subtropical cities face severe microclimatic challenges where hyper-dense urban configurations frequently exacerbate urban heat island effects and reduce street-level wind ventilation. This paper presents a novel coupled framework combining Computational Fluid Dynamics (CFD) and Space Syntax analysis to evaluate pedestrian thermal comfort within Hong Kong's predominant podium-tower typologies. By integrating ENVI-met 5.0 numerical microclimate simulations with DepthmapX spatial topological models, we examine the intersection of physical microclimatic stress—measured via the Physiological Equivalent Temperature (PET)—and pedestrian movement probability across high-density streetscapes. The investigation analyzes three representative podium-tower configurations in Mong Kok and Central, Hong Kong, during summer peak solar conditions. Results demonstrate that continuous, unpermeable podium blocks produce stagnant wind zones (wind velocity < 0.5 m/s) and severe thermal discomfort (PET > 42°C) along high-integration pedestrian routes. Conversely, spatial configurations featuring elevated walkways, ground-floor setbacks, and podium voids increase wind speed by up to 1.8 m/s, reducing average ground-level PET by 3.4°C along primary pedestrian corridors. The coupled spatial-microclimatic assessment methodology provides urban designers and planners with a quantitative, human-centered tool to optimize street-level comfort without sacrificing high-density urban development efficiency.
