The saturation of wind resources in onshore plains and nearshore regions highlights the requirement of expand wind energy development through large-scale vertical axis wind turbines (VAWTs). However, current researches on large VAWT wakes lack long-term, high-resolution, three-dimensional field measurements, leaving key wake characteristics insufficiently resolved. This research investigates the wake of a 15 kW straight-blade VAWT (H-VAWT) based on continuous multiplane LiDAR measurements to quantify wake velocity, turbulence intensity, and vorticity. The results indicate that velocity recovery is faster in top and bottom regions (14 D, diameter) than at the hub (16 D), with the wake center showing a persistent lateral offset of up to 0.55 D due to counter-rotating tip and hub vortices. The wake width is largest at the hub (2.53 D) and narrower at the blade top (2.09 D). Turbulence intensity peaks at 30% in the hub region with an influence range of y/D≈±1.2. Vorticity remains elevated up to x/D=12 at the hub and displays secondary enhancement at x/D≈6 near the blade top. Strong asymmetry is observed in velocity, turbulence, and vorticity distributions, with the upstream tip-vortex side recovering most rapidly and the hub-centered region recovering most slowly. Wake behavior transitions from complex vortex interactions in the near wake (x/D4) to Gaussian-like diffusion in the far wake (x/D4), with distinct horizontal and vertical spreading rates. These findings provide an empirical foundation for improving aerodynamic performance and supporting the scale-up of H-VAWT arrays.
Yue et al. (Wed,) studied this question.