Exploring computational fluid dynamics to assess the role of vegetated planters in urban canyon microclimate regulation

Accurately modelling urban microclimates is essential for developing effective mitigation strategies against urban overheating. This study assesses the potential of ANSYS Fluent to simulate an experimental urban canyon with vegetated planters, using three different simulation methods. The analysis focuses on accuracy, operational suitability, and an improved understanding of the physical mechanisms operating at the scale of an urban canyon. Numerical results related to radiative, thermal, and aerodynamic fluxes, are evaluated based on (i) experimental data obtained from a dense network of sensors and (ii) the physical consistency obtained in the spatial distribution of the variables analysed. Despite some discrepancies in spatial and temporal variations, the model demonstrated strong agreement with experimental data, with absolute errors in air temperature and relative humidity below 3 % on average (maximum 11 %). Radiation, as the most sensitive factor for daytime thermal comfort variation in the study area, highlights the importance of improving radiative exchange in the proposed models. While certain software limitations require user-defined functions, such as representation of average radiant temperature, thermal comfort indices and multiple vegetation heat source terms, the study underscores the tool’s capacity to generate detailed and high-resolution microclimate data. This rich numerical database improves our understanding of urban heat dynamics, paving the way for more efficient urban climate solutions.