Effects of wind-gathering cascade structural optimization and blade tip modification on the aeroacoustic performance of roof-mounted concentrator wind turbines

Abstract

To enhance aerodynamic performance and suppress operational noise of roof-mounted concentrator wind turbines, this study proposes a synergistic scheme integrating concentrator cascade structural optimization and blade tip leading-edge perforation. First, Venturi-effect-based 3D numerical simulations optimized cascade parameters (8° windward, 15° leeward, 0.23 m spacing, 1.40 m pitch), significantly increasing the wind concentration ratio and flow stability. Second, Large Eddy Simulation (LES) coupled with the Ffowcs Williams-Hawkings (FW-H) acoustic analogy evaluated leading-edge micro-perforations to mitigate broadband noise. Results indicate that an optimal 1.5 mm hole diameter achieves moderate pressure relief, effectively disrupting the spanwise coherence of leading-edge pressure fluctuations and accelerating large-scale tip vortex breakdown. Consequently, this scheme realizes full-spatial noise reduction, decreasing the low-frequency peak sound pressure level (SPL) by 5.3 dB while simultaneously improving aerodynamic power. This provides a novel aeroacoustic design framework for urban micro-wind systems.