A study of wind-wave misalignment for the Irish coastline and its effect on the wind turbine response

Abstract

A wind turbine is one of the largest rotating structures on earth. More wind turbines are now being developed with taller towers and longer blades, making them more flexible. As a result, an offshore wind turbine can exhibit a significant dynamic response. The wind turbines are subjected to a time-varying, highly turbulent loading environment. The wind and wave loads may not always act in the same direction during the wind turbine operation. The misaligned wind-wave loading can excite the less damped side-to-side mode of vibration for a wind turbine, exhibiting an amplified response for a prolonged period. Therefore, the assumption of co-directionality of wind and wave forces may not always represent conservative wind turbine design. The wind- wave misalignment is a local phenomenon, and it depends on the properties of the coast and wind profile. This paper studies the characteristics of wind-wave misalignment for the East Coast of Ireland and its impact on the system loads and deformations. The environmental data from Irish Marine Weather Buoy Network (IWMBN) is used in this study. This study uses environmental data from the Irish Marine Weather Buoy Network (IWMBN). This network of five offshore buoys monitors weather and oceanographic conditions for the Irish coast in real-time. The method of bins is used to study the statistical properties of wind speed and wind-wave misalignment. The response of the IEA 15MW reference wind turbine model with a monopile foundation for co-directional and misaligned wind-wave loading is simulated using OpenFast. It has been observed that misaligned wind- wave loading amplifies the wind turbine response for some operating conditions.