Understanding how wind turbine blade damage affects air flow and noise generation

As more and larger wind turbines are built, detecting structural damage on turbine blades becomes more important. One goal of the wind energy field is to develop flexible and cost-effective detection and monitoring frameworks that can reduce maintenance expenses and minimize the operation risk of wind farms.

Zhang et al. investigated an aeroacoustics-based approach toward developing a remote, non-contact damage detection and monitoring framework. By deepening understanding of how damage affects the underlying aerodynamics and aeroacoustics, their study provides insights necessary to assess such methods.

Studying an airfoil in a wind tunnel under both clean and turbulent inflow conditions, they found that a crack at the trailing edge will alter the properties of the boundary layer and flow field around the blade. The crack increased velocity gradients near the trailing edge and reduced the size of coherent vortex structures in the near-wake.

Compared to clean inflow conditions, inflow turbulence reduced the size of the coherent vortex structures. This suggests that existing models for predicting aerodynamic noise, which were originally developed for clean inflow, must be modified for turbulent inflow conditions.

“This study advances the fundamental knowledge of vortex dynamics and aeroacoustics associated with cracked blunt trailing edges in turbulent flow environments, which is essential for improving predictive models and future damage detection strategies,” said author Yanan Zhang. “This work lays the foundation for future applications in real wind farms, where it can enable effective, remote, and real-time monitoring of wind turbines.”

This experiment examined an airfoil section; next, the authors will test these results with a scaled rotating wind turbine in a wind tunnel, using blades subjected to fatigue-induced damage.

Source: “On the impact of turbulent inflow and crack-induced blunt trailing edge on the flow field and far-field noise of an airfoil,” by Yanan Zhang, Simon Watson, Daniele Ragni, and Francesco Avallone, Physics of Fluids (2025). The article can be accessed at https://doi.org/10.1063/5.0299883 .