Researchers from the University of Rennes 1 and the University of Twente have published a study in the Journal of Fluid Mechanics that sheds light on how wind farm design and airflow dynamics influence noise generation and propagation. The team, led by Dr. Jérôme Colas and Dr. Riccardo Stevens, used advanced numerical simulations to model wind turbine noise and its behavior within wind farms.
The study demonstrates that the flow physics within wind farms significantly affect both the generation and downstream propagation of noise. Using large-eddy simulations (LES) to model the flow field, the researchers found that in the first row of turbines, turbulence-induced noise (TIN) and trailing edge noise (TEN) contribute equally to the overall noise. TIN dominates at low frequencies, while TEN is more prominent at higher frequencies. As the airflow moves downstream, TEN decreases due to reduced wind speeds, but TIN persists because of increased turbulence dissipation.
The layout of the wind farm plays a crucial role in these dynamics. Aligned wind farms, where turbines are positioned in straight rows, experience stronger wake interactions, leading to more pronounced noise reduction downstream. However, staggered layouts, where turbines are offset, produce more noise overall because individual turbines operate at higher wind speeds. Additionally, the study found that the wake superposition in wind farms modifies sound focusing, resulting in different amplification areas compared to isolated turbines. Staggered layouts, in particular, show enhanced sound focusing downwind due to the positioning of turbine wakes, leading to higher sound levels and greater amplitude modulation.
These findings highlight the importance of integrating flow and acoustic models to accurately assess the environmental impact of wind farms. Current models based on isolated turbines do not capture these complex interactions, which could lead to underestimations of noise levels in real-world scenarios. By understanding these dynamics, wind farm developers can optimize layouts and operational strategies to minimize noise pollution and improve community acceptance.
The research underscores the need for more sophisticated modeling approaches that consider the interplay between airflow and acoustics in wind farms. As the energy sector continues to expand wind power capacity, these insights will be valuable for designing quieter, more efficient wind farms that align with environmental and regulatory standards.
This article is based on research available at arXiv.