In this study, computational fluid dynamics (CFD) is employed to evaluate the influence of surrounding buildings on the performance of a roof-mounted, 2-bladed Savonius vertical-axis wind turbine (VAWT). The latter is planned to be located in the Bovisa Campus of Politecnico di Milano. In the present work a preliminary simulation campaign has been conducted, explicitly depicting the surrounding area and employing an advanced Reynolds-averaged Navier-Stokes (RANS) model. This closure is suitable for Atmospheric