Ducted wind turbines in yawed flow: A numerical study

Abstract. Ducted Wind Turbines (DWTs) can be used for energy harvesting in urban areas where non-uniform flows are caused by the presence of buildings or other surface discontinuities. For this reason, the aerodynamic performance of DWTs in yawed flow conditions must be characterized. A numerical study to investigate the characteristics of flow around two DWT configurations using a simplified duct-actuator disc (AD) model is carried out. The analysis shows that the aerodynamic performance of a DWT in yawed flow is dependent on the mutual interaction between the duct and the rotor; an interaction that changes with duct geometry, AD loading and operating conditions. It is found that the duct cross-section camber not only offers insensitivity to yaw, but also a gain in performance up to a specific yaw angle; thereafter any further increase of yaw results in a performance drop.