Wind Farm Noise Impact Assessment Source and Characteristics – Different types of wind turbine
Subjective noise from wind turbines Higher frequencies Swishing, lapping, hissing, whistling… Mid frequencies Tones, whines, roar… Lower frequencies Rumble, thumping…
Principal Sources of Noise Aerodynamic sources Motion of air around the blades Various sources, complex mechanisms Mechanical sources Motion of mechanical & electrical components Sources are more easily identified and controlled Aerodynamic sources affected by air inflow speed and turbulence All sources affected by rotor speed and loading
Separation (stall) noise Aerodynamic sources (after Hayes, IOA 25-04-2006 and Lowson) Separation (stall) noise Tip noise Trailing edge noise Boundary layer noise Turbulence ingestion Dominant
Comparison of sound power outputs of different wind turbines…. Turbine sound output levels are wind speed dependent Actual variation with wind speed is turbine specific Common now for large turbines to be pitch-regulated variable speed
Evolution for a particular model
Capacity of variable speed pitch-regulated turbines Reduced noise modes Capacity of variable speed pitch-regulated turbines Most turbines offer reduced noise mode operation Speed restriction or pitch setting change Cost is power generation loss but can be restricted to specific conditions
Thank you