Although the characteristic Reynolds number of small horizontal axis wind turbines is only in the order of 100,000, their noise emissions can be annoying. Three different modifications of the blades aiming at attenuating the aerodynamic noise mechanisms are investigated: (i) Optimization of the blade profile, (ii) application of boundary layer tripping and (iii) addition of serrations to the trailing edges of the blades. All modifications were designed using either a novel optimization method or state-of-the-art design rules. They were tested on a three-bladed research wind turbine with 3 m diameter, which was placed on a large flat roof of an isolated tall building. Shaft and sound power were measured during substantial time periods, statistically analyzed and compared. Depending on the type and thickness of the blade profile, both, tripping and trailing edge serrations, were found to reduce noise but always degraded the turbine shaft power. The model-based optimization of the 15 % thick baseline profile S834 resulted in a new 10 % thick profile with a novel shape of the pressure and suction sides. Blades made from this profile, without trips but with trailing edge serrations, provided the best compromise between noise reduction and degradation of the aerodynamic turbine performance.

尽管小型水平轴风力发电机的特征雷诺数仅为100,000，但其噪声排放却令人讨厌。研究了旨在减弱空气动力噪声机理的叶片的三种不同修改形式：（i）优化叶片轮廓；（ii）边界层脱扣的应用；（iii）在叶片后缘增加锯齿。所有修改都是使用新颖的优化方法或最新的设计规则进行设计的。他们在直径3 m的三叶片研究型风力涡轮机上进行了测试，该风力涡轮机放置在隔离的高层建筑的大平屋顶上。在相当长的一段时间内测量轴和声功率，进行统计分析和比较。根据叶片轮廓的类型和厚度，两者 发现跳闸和后缘的锯齿可减少噪音，但始终会降低涡轮轴的功率。基于模型的15％厚基线轮廓的优化S834产生了新的10％厚轮廓，并具有压力侧和吸力侧的新颖形状。由这种轮廓制成的叶片没有跳动，但具有后缘锯齿，在降噪和空气动力涡轮性能下降之间提供了最佳折衷方案。