Wind Turbine Noise Reduction

Xi Engineering Consultants Ltd, Edinburgh, UK

Xi Engineering Consultants Ltd specializes in complex vibration issues, like those caused by wind turbines. The meshing of teeth within the gearbox of a wind turbine can cause great vibrations which are perceived as excessive noise. This presents a problem as there are strict regulatory standards throughout Europe and North America limiting permissible noise from these structures.

Studying the design data lead engineers to conclude that this gearbox was the source of the noise and vibration, and that it was being amplified by the tower’s steel skin. Using a COMSOL model of the structure, they were able to locate hot spots where the noise was being amplified and test various solutions. The solution found was to use a specific material to coat the inside of the tower and reduce the amplification. Due to the materials high cost, they used COMSOL to determine the least amount of material necessary to keep the noise levels below the required standards.

Acoustic-structural interaction model of a wind turbine surrounded by air showing the vibration acceleration amplitude of the turbine and slices through the air showing the resultant sound pressure level.