The wind turbine wake is a downstream region of velocity deficit, resulting in a power loss for downstream wind turbines. A turbulator is proposed to minimize this velocity deficit. In this work, a very successful field test campaign was executed which demonstrated the use of segmented Gurney Flaps as a promising add-on to promote enhanced wind turbine wake recovery for improved overall wind farm farm performance.

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. It is found that the duct cross-section camber offers not only insensitivity to yaw but also a gain in performance up to a specific yaw angle; thereafter any further increase in yaw results in a performance drop.

Multi-element ducts are investigated to further improve the aerodynamic performance of ducted wind turbines. CFD simulations are performed for a multi-element duct geometry consisting of a duct and a flap; the goal is to evaluate the effects on the aerodynamic performance of the radial gap length and the deflection angle of the flap. Increasing the radial gap length results in an augmentation of the total thrust generated by the DWT, whereas a larger deflection angle has an opposite effect.

Predicting the 50-year extreme loads for wind turbines requires a tremendous computational effort. Therefore, designers often have to extrapolate from relatively small data sets and have to settle for some degree of uncertainty. We investigated the impact of this uncertainty on practical design problems by drawing subsets from a 96-year load data set and using a crude Monte Carlo method to find the 50-year load. The results show that designers have to be careful with selecting sample sizes.

The flow in the blade root region of horizontal axis wind turbines is highly three-dimensional. Furthermore, it is influenced by the presence of strong trailing vortices. In this work we study the complex root flow by means of experiments and numerical simulations. The simulations are shown to be reliable at predicting the main flow features of the rotor blades. Additionally, new insight into the physical mechanisms governing the blade root aerodynamics is given.