Vertical axis wind turbines (VAWTs) can enhance aerodynamic performance through wake interaction, but this also affects noise characteristics. This study investigates the influence of wake interference on noise in a twin-VAWT array using an Improved Delayed Detached Eddy Simulation coupled with the Ffowcs Williams–Hawkings acoustic analogy. By analyzing flow structures and acoustic directivity in comparison to an isolated turbine case, correlations between wake vortex evolution and noise features were established, uncovering the underlying mechanisms of noise alteration. Results show that the windward wake diffusion of the upstream turbine (Turb I) is suppressed, accelerating flow in the upwind region of the downstream turbine (Turb II). Along the centerline between the turbines, along the centerline between turbines, interactions among vortices from Turb I, the strong vortex shed by Turb II near 150°, and turbulent mixing raise the sound pressure level by 9.52 dB. Turb I's vortex shedding dynamically correlates with hump-shaped noise features in Turb II's upwind and leeward regions. The near-field decay rate of the wake from Turb II increases by 22.54% compared to the isolated turbine, while Turb I maintains a high noise level above 99.7 dB within the 1.5R–3R range. Phase difference is identified as a key control parameter that reshapes vortex–acoustic coupling without compromising power output, thereby modifying noise spectral humps and enabling spatial redistribution of acoustic energy. These findings provide a theoretical basis for noise control and performance optimization in turbine arrays.
Zhao et al. (Thu,) studied this question.