AEROELASTIC AND STRUCTURAL DYNAMICS OF WIND TURBINES: AN OPENFAST-BASED COMPUTATIONAL STUDY

Abstract

Wind energy has become a critical component of the renewable energy sector, necessitating advanced computational models to enhance wind turbine performance and structural resilience. This study employs OpenFAST, a multi-physics simulation tool developed by NREL, to investigate the aeroelastic and structural dynamics of the onshore configuration of the NREL 5-MW reference wind turbine — a model originally developed for offshore applications but widely used in both onshore and offshore research contexts. The primary objectives include analyzing turbine eigenmodes, assessing power-thrust characteristics, and evaluating blade bending moments under both steady and turbulent wind conditions. Eigenmode analysis reveals significant out-of-plane bending in the first blade mode and coupled bending-torsional motion in the tower, emphasizing the importance of structural optimization. The power curve exhibits a rapid increase up to the rated wind speed of 12–15 m/s, stabilizing due to active pitch control mechanisms that regulate aerodynamic loads. The thrust force peaks at 11-12 m/s, marking a transition in aerodynamic loading before pitch adjustments mitigate further increases. Under turbulent wind conditions, increased fatigue loads and structural oscillations highlight the necessity for robust damping techniques and fatigue-resistant materials to ensure long-term reliability. The results underscore the significance of aeroelastic interactions, and structural flexibility in optimizing wind turbine longevity and operational efficiency. Further research could explore larger-scale systems, such as the openly available IEA 15MW Reference Wind Turbine and their digital twin’s development.