Near wake of the X-Rotor vertical-axis wind turbine

Abstract

In the present study, the near wake of a novel vertical-axis wind turbine known as the X-Rotor is experimentally investigated. Particle image velocimetry is used to measure the phase-locked flowfield at several streamwise locations within the rotor's volume of rotation. The results show a clear impact of coned blades on the streamwise and axial induction fields as well as the local presence of vorticity structures. A notable counteraction of the average expansion of the wake in the axial direction is observed stemming from the shed and tip vorticity of the coned blades. As a result, an axial contraction and radial expansion in the wake can be observed across several phase and cross-stream combinations as well as a consistent asymmetry in streamwise flow. These results encourage the development and validation of numerical models that can account for the three-dimensional induction field of the X-Rotor as well as a further study into the far wake and farm-level installation of vertical-axis wind turbines.