Moving tornado-induced effects on a wind turbine : insights into dynamic load responses

Abstract

Wind turbines are essential for harnessing wind energy, but their performance and safety are significantly challenged by extreme weather conditions, such as tornadoes. This study investigates the aerodynamic and flow field characteristics of wind turbines subjected to a moving tornado environment. First, a large eddy simulation model is used to simulate the tornado wind field, with its accuracy validated against real tornado data. A numerical wind tunnel is then constructed and validated using the NREL 5 MW wind turbine model. Subsequently, a moving tornado is introduced into the numerical wind tunnel, considering various relative positions of the turbine. The results show that the moving tornado exerts substantial dynamic wind loads on the turbine, with the load in the windward direction being particularly significant. Different rotor blades exhibit varying sensitivities to these loads, revealing distinct weak points. The tower mainly experiences horizontal loads. Key factors, including relative positions and the spatial configuration of the blades after shutdown, are crucial for understanding the tornado-induced loading on the turbine. The dynamic pressure response of the turbine is marked by a sharp decrease followed by a gradual recovery, reflecting the passage of the tornado. Visualization of vortex shedding and dissipation underscores their considerable impact on the velocity distribution within the flow field, explaining the variations in flow disturbances at different relative positions. The findings of this study provide valuable insights into optimizing wind turbine design and developing effective protective strategies against tornado-induced damage.