Influence of Various Urban Morphological Parameters on Urban Canopy Ventilation: A Parametric Numerical Study

Abstract

Numerical simulation is vital for evaluating urban ventilation. However, accurate urban-scale ventilation modeling requires extensive building surface simulation for computational demand. The distributed drag force approach simplifies the urban canopy by modeling buildings as a porous volume that accounts for momentum and turbulence. This method is a practical solution for simulating urban airflow. The drag force coefficient (Cd) is a crucial aerodynamic parameter in this approach. This study examines how Cd varies with urban design parameters such as plan area density (λp), average building height (H), frontal area density (λf), floor aspect ratio (AR), and sky view factor (SVF). Employing extensive numerical simulations conducted under neutral atmospheric conditions, we explore ranges of λp = 0.04–0.07 and λf = 0.1–1.2. The numerical model has been validated against existing wind tunnel data. The results show that Cd is insensitive to the model scale and background wind speed. We discover a nonlinear relationship between Cd and the parameters λp, λf, and SVF. For urban layouts with cubic-shaped buildings, Cd peaks at different λp within the range of 0.2~0.8. When λp and H are constant, Cd has a linear relationship with AR and λf. It is recommended to use λp, SVF, and AR as predictors for Cd across various urban configurations.

A New Method Based on Lattice Boltzmann Method and Unsupervised Clustering for Identification of Urban-Scale Ventilation Corridors

“…In recent years, with the acceleration of global urbanization, urban climate issues have gradually become one of the focuses of widespread attention [1][2][3][4][5]. As an important means to mitigate the urban heat island effect, regulate the urban climate, improve air quality and enhance urban livability, urban ventilation corridors have received more and more attention from scholars and urban planners [6][7][8][9][10]. In urban design, understanding the distribution of urban ventilation corridors is of great significance for improving the quality of the urban ecological environment [11][12][13][14][15].…”