Wind turbine blades are very noisy

Do wind turbines make noise?

Yes, wind turbines generate two types of noise: aerodynamic noise and mechanical noise. The aerodynamic noise is generated from the blades as they pass through the air. The loudness of the aerodynamic noise is related to how fast the tip of the blades are spinning, the size of the blades, and the wind speed.

What is the dominant noise source of a wind turbine blade?

However, provided that mechanical noise is adequately treated, aerodynamic noise from the blades is generally the dominant noise source. Therefore, in this section we will briefly discuss the flow around a wind turbine blade, followed by a description of potential aerodynamic source mechanisms.

What causes aerodynamic noise from wind turbines?

Aerodynamic Noise Sources Aerodynamic noise is flow induced noise caused by interaction of flow structures with the blade wall. Aerodynamic noise from wind turbines can be classified as inflow turbulence noise and airfoil self-noise. Relative contribution of individual sources to total noise are shown in Fig. 3.

How to predict wind turbine noise?

The swishing character of the sound can be explained by trailing edge noise directivity and convective amplification. A semi-analytical, semi-empirical prediction method can accurately predict the characteristics of wind turbine noise. Wind turbine noise can be halved by means of serrations, without adverse effects on the aerodynamic performance.

How to reduce noise in a wind turbine?

Several techniques for noise mitigation have been discussed. Methods like serrated trailing edges for trailing edge noise reduction are already being used in some turbines but more effective methods for noise control are needed.

Why do turbine blades make so much noise?

This strong speed dependence of the sound level is the main reason why practically all turbine noise is produced by the outer part of the blades: doubling the flow speed (all else being equal) results in an increase in source strength of 15 dB!