Designing breezeways to enhance wind environments in high-density cities: A comprehensive analysis of ten morphological parameters

To advance urban breezeway designs, this paper presents a pioneering and comprehensive study of breezeway morphological parameters. Ten parameters, identified through extensive literature review, include coverage ratio, porosity, line density, sinuosity, rotation angle, width, length, average height, height variation, and aspect ratio. Regression analysis, utilizing over 200 data points collected from wind tunnel experiments in Hong Kong, established correlations between these parameters and pedestrian-level wind velocity ratio (VR_point). Results reveal that among the 2D parameters, width, length, line density, and coverage ratio exhibit the strongest correlations with VR_point, while aspect ratio and porosity emerge as significant factors among the 3D parameters. Notably, simple 2D parameters, coverage ratio and width, can effectively substitute for their 3D counterparts, porosity and aspect ratio, in high-density urban environments. Furthermore, the results highlight the relative contributions of different parameters to urban ventilation. From a street-level perspective, VR_point is primarily influenced by configurations of street segments (width, 80 %) and street intersections (rotation angle, 20 %). From a neighborhood-level perspective, permeability (coverage ratio, 35 %), fragmentation (line density, 30 %), and roughness (average height, 35 %) are critical factors. Illustrative examples are provided to help translate these findings into spatial analysis tools and design guidelines, aiding planners and decision-makers in improving urban living environments.