Визначення впливу модифікації задньої крайки лопаті турбіни вітрогенератора на аеродинамічний шум

This study investigates acoustic processes that occur during the flow of air around the blade segment of a wind turbine. The issue of aerodynamic noise generated by wind turbines is one of the factors that hinders the widespread implementation of wind turbines. Noise reduction is possible by changing the design of the turbine blade to influence the aerodynamic processes during the flow of air around it. This paper reports an experimental study on the possibility of reducing the aerodynamic noise of wind turbines by modifying the trailing edge of the blade. An original methodology of acoustic experiments in an anechoic chamber is described; the results of experimental studies are given. Two different modifications of serrated trailing edges of the blade with the NACA0012 aerodynamic profile have been considered: a flat serrated edge and a three-dimensional serrated edge. The results from aerodynamic noise measurements of the prototypes of the blade segments were compared with the noise from the basic original sample. Acoustic measurements were carried out in the range of flow speeds: 7.5–20 m/s and angles of attack 0–15°. The results demonstrated that both configurations of the serrated trailing edge make it possible to reduce the level of aerodynamic noise compared to the base segment. It was found that the noise reduction occurs at relatively small angles of attack (0–5°) and moderate flow speeds (up to 15 m/s). In the specified range of parameters, the reduction of aerodynamic noise occurred due to a decrease in the sound pressure level in a certain frequency range by up to 4 dB. The segment with flat serrations turned out to be somewhat more effective in terms of noise reduction in the low-frequency range. Results of this work could be used when designing new generation wind energy systems with reduced noise levels, as well as other aerodynamic devices.