Modeling wind farm noise emission and propagation: Effects of flow and layout

This study demonstrates the influence of wind farm flow on noise generation and downstream propagation through numerical simulations. Time averaged flow fields, modeled using large-eddy simulations, serve as input to acoustic models that predict wind turbine noise. In the first turbine row, turbulent inflow noise and trailing-edge noise contribute equally, with turbulent inflow noise dominating at low frequencies and trailing-edge noise at higher frequencies. Farther downstream in the wind farm, trailing-edge noise’s relative contribution decreases because the wind speed is lower, while turbulent inflow noise persists because turbulence levels remain high. These effects are more pronounced in aligned wind farms than in staggered layouts, given stronger wake interactions. However, staggered farms produce more noise overall because turbines operate at higher wind speeds. Additionally, wind farm flow significantly affects sound propagation downwind. Wake superposition changes sound focusing, modifying amplification areas compared to an isolated turbine. For a staggered layout, it particularly shows enhanced sound focusing downwind. This leads to higher sound levels and amplitude modulation downwind of the wind farm, compared to an aligned layout. These phenomena are not captured by models based on isolated turbines. These findings underscore the importance of integrating flow and acoustic models to more accurately assess the environmental impact of wind farms.