Influence of atmospheric thermal stability on wake meandering of a large-scale wind turbine

The evolution process of wind turbine wake structures under different atmospheric thermal stabilities was simulated based on large eddy simulation with the actuator line model. It examined how thermal stability affects the structural scale and dominant factors of wake meandering and revealed the spatiotemporal evolution patterns of wake coherent structures through proper orthogonal decomposition and spectral proper orthogonal decomposition methods. The results indicate that as atmospheric stability increases, the structural scale of wake meandering decreases while its dominant frequency increases. Additionally, the driving mechanism shifts from passive entrainment by external turbulence to active development driven by internal shear instability within the wake. This transition is manifested as a marked increase in the shear layer instability frequency in the power spectral density. The highest spectral peak is observed under neutral conditions, while the spectral peaks under convective and stable conditions are 0.76 and 0.54 times, respectively, indicating that large-scale disturbances in the inflow exert a strong activating influence on the development of wake meandering.