Aerodynamic design optimization of ducted openings through high-rise buildings for wind energy harvesting

On-site renewable energy generation in the built environment can be achieved by incorporating wind turbines in the integral design of buildings. Passages through buildings are considered promising to strengthen the local wind resource availability but information concerning their design and performance is scarce. Therefore, two key design parameters that can enhance the wind energy performance of ducted openings in high-rise buildings are addressed and optimized via CFD simulations: the fillet radius (r) of the opening and the duct diameter (d0). 3D steady RANS simulations are performed and validated with wind tunnel data from the literature. Fillets are shown to suppress flow separation, thereby enhancing the magnitude and uniformity of the wind speed in the duct and reducing the turbulent kinetic energy. With a reference diameter d0 = D, the best-performing configuration has a normalized fillet radius r/d0 = 0.2, which increases the average wind speed in the duct by 65% and the wind power by 354%. Modifying the duct diameter alone has limited influence. However, combining a larger duct diameter d0 = 1.5D with fillets with r/d0 = 0.4, can yield up to 78% increase in average wind speed and 650% in wind power density. Findings indicate that the dimensionless wind speed in the duct (U/U0) scales closely in proportion to the normalized fillet radius (r/d0). With these results, the present study demonstrates the aerodynamic advantage of ducted openings in buildings and identifies relevant design conditions required to improve the wind resource availability for the prospective implementation of wind turbines.