Bioinspired Trailing Edge Serrations for Vertical Axis Wind Turbine Blades in Urban Environments: Performance Effects

Abstract

Biomimetics has recently emerged as an interesting approach to enhance renewable energy technologies. In this work, bioinspired Trailing Edge Serrations (TES) were evaluated on a typical Vertical Axis Wind Turbine (VAWT) airfoil, the DU06-W200. As noise reduction benefits of these mechanisms are already well-established, this study focuses on their impact on airfoil and VAWT performance. A saw-tooth geometry was chosen based on VAWT specifications and existing research, followed by a detailed assessment through wind tunnel tests using a newly developed aerodynamic balance. For a broad spectrum of attack angles and Reynolds numbers, lift, drag, and pitching moments were carefully measured. The results show that TES enhance the lift-to-drag ratio, especially in stalled conditions, and postpone stall at negative angles, expanding the effective performance range. A notable increase in pitching moment also is also observed, relevant for blade-strut joint design. Additionally, the impact on turbine performance was estimated using an analytical model, demonstrating excellent accuracy when compared against previous experimental results. TES offer a modest 2% improvement in peak performance, though they slightly narrow the optimal tip-speed ratio zone. Despite this, the potential noise reduction and performance gains make TES a valuable addition to VAWT designs, especially in urban settings.