An experimental study on the influence of gust and debris on the wake flow characteristics of wind turbines*

The operational efficiency of wind turbines is highly dependent on environmental conditions. Impacting particles such as hail, dust, rain, and other debris that may be suspended in the air, such as during a strong wind gust, can significantly impact the wind turbines and overall performance of wind farms over the short and long term. As a result, studying the characteristics of the flow during such intense events is essential, with the aim of developing mitigation strategies. In this experimental study, we attempt to simulate gust events that are sufficiently strong to suspend particles that subsequently impact small-scale wind turbines. A porous disk is placed in a water tank where rotating impellers generate the background turbulence field. A strong gust event is intermittently introduced by deformation of the flow field resulting from the motion of a rapidly moving plate. The fluid is seeded with inertial particles that settle on the bottom of the turbulent flow field but are resuspended due to the gust event. Particle Image Velocimetry and Lagrangian Particle Tracking are used to analyze the flow field in the near wake behind the porous disk.