Impact of wind direction on wind energy potential for building-integrated ducted wind turbines: A numerical analysis

Abstract

The aerodynamic performance of building-integrated ducted wind turbines depends on several parameters such as the duct geometry, variation in wind speed and direction (which are inherent characteristics of the urban wind). This study focuses on the impact of wind direction on wind energy potential of a previously optimized building-integrated duct geometry [1], embedded in a generic isolated high-rise building. The mean power density at the duct throat (where the turbine can be installed) is investigated in four wind directions of θ = 0°, 30°, 60° and 90°. High-fidelity steady RANS simulations, validated with experimental data, are used. The results show that the studied duct can increase the mean power density at its throat (i.e. rotor plane) up to 7.08 - 24.8 times that of the freestream flow at the same height for a wide range of -60° ≤ θ ≤ 60°. The variation of wind energy potential in different wind directions is shown to be due to the increased size of the nozzle stagnation and separation regions for θ > 0° which limit the nozzle effective area and lower flowrate through the throat. Flow deviation from the duct central axis towards its walls further depletes the wind energy in friction.