**Gilberto Santo 1,\* , Mathijs Peeters <sup>2</sup> , Wim Van Paepegem <sup>2</sup> and Joris Degroote <sup>1</sup>**


Received: 4 December 2019; Accepted: 15 January 2020; Published: 21 January 2020

**Abstract:** The effect of a wind gust impacting on the blades of a large horizontal-axis wind turbine is analyzed by means of high-fidelity fluid–structure interaction (FSI) simulations. The employed FSI model consisted of a computational fluid dynamics (CFD) model reproducing the velocity stratification of the atmospheric boundary layer (ABL) and a computational structural mechanics (CSM) model loyally reproducing the composite materials of each blade. Two different gust shapes were simulated, and for each of them, two different amplitudes were analyzed. The gusts were chosen to impact the blade when it pointed upwards and was attacked by the highest wind velocity due to the presence of the ABL. The loads and the performance of the impacted blade were studied in detail, analyzing the effect of the different gust shapes and intensities. Also, the deflections of the blade were evaluated and followed during the blade's rotation. The flow patterns over the blade were monitored in order to assess the occurrence and impact of flow separation over the monitored quantities.

**Keywords:** fluid–structure interaction; wind turbine; atmospheric boundary layer; composite materials; gusts; wind energy
