Abstract
As the global population gravitates towards urban areas, the demand for construction and housing rises, influencing the dynamics of air flow, pollution concentrations, and overall air quality. Because of the impact of these trends on air quality, natural ventilation, and pollutant dilution in urban environments, there is the need for solutions able to make cities not only healthier but also more resilient, and sustainable. In this context, this study delves into the effects of building structures and street canyons on natural ventilation potential. Two primary ventilation methods, mechanical and natural, are typically available as a design choice. While mechanical systems have drawbacks such as additional energy consumption, natural ventilation emerges as an alternative, with wind-driven, pressure-driven and buoyancy-driven approaches being explored. This thesis investigates the influence of urban morphology, street canyons, and building layouts on natural ventilation potential. This research explores the effects of air displacement around buildings in urban street canyons on natural ventilation potential, employing a combination of Computational Fluid Dynamics (CFD) simulations and wind-tunnel experiments for both generic and real case studies. The research activity begins with CFD simulations on generic building layouts. Various turbulence models, such as standard k−ϵ, realizable k−ϵ, and RNG k−ϵ turbulence model, are discussed in the context of CFD simulations, providing insights into their applicability based on computational resources and accuracy requirements and, at the end, utilizing the standard k−ϵ turbulence model for the simulations following the mesh independency analysis. Subsequent Air Changes per Hour (ACH) calculations indicate satisfactory airflow around and indoors of buildings, contributing to comfortable conditions. Validation of simulation results is achieved through Particle Image Velocimetry (PIV) applied to experiments on reduced-scale models, demonstrating good agreement. Real case study on a building at the city-center campus of Free University of Bozen-Bolzano, Italy, (i.e., the E-building) further confirms the turbulent behavior of air and its potential for natural ventilation. In the end, the outcomes can be served as a valuable guide for future research endeavors, aiding urban planners, architects, and engineers in enhancing ventilation strategies for sustainable and inclusive urban development.