Objetivo
The purpose of the project is
- to gather statistical information on individual differences in acoustics by measuring series of existing turbines and
- to develop and validate a wind turbine specific sound propagation model by experimental research using artificial sound sources and using wind turbines.
The deliverables for this project are:
1. The measured acoustic source power of six commercial wind turbine types, 5 individual turbines per type (total 30 turbines).
2. An experimentally validated sound propagation model for wind turbine applications taking the effect of ground impedance as well as wind and temperature shear into account.
In planning and licencing procedures of wind farms, authorities have to predict the acoustic noise levels due to the planned wind farm at the nearest dwelling. The prediction is normally done by using the acoustic characteristics such as sound power and tonality that have been measured at a turbine of the same type (or batch) as planned. Further the propagation of sound from the turbines to the dwelling is calculated using general models. This procedure introduces two uncertainties :
- the uncertainty of possible individual differences between the acoustic characteristics of turbines of the same type and
- the uncertainty of the propagation model due to turbine specific situations as wind speed, wind shear and source elevation.