A study on the effect of different modeling parameters on the dynamic response of a jacket-type offshore wind turbine in the Korean Southwest Sea

As a country mostly surrounded by water, Korea has good potential for offshore wind energy utilization. With offshore wind turbines growing larger and with increasing water depth, jacket structures are attracting increased attention because they appear to be cost-effective, but they are still at an early stage of development for use in the offshore wind industry. This paper aims to design a jacket structure to support a 5MW wind turbine in 33m deep water for a Korean offshore demonstration project and to investigate the effects of different modeling parameters (including joint can, overlap, flooding of the member, marine growth and mass of the transition piece) on the dynamic response of an offshore wind turbine with a jacket substructure. For this purpose, modal analysis and aero-servo-hydro-elastic simulation with varying modeling parameters are performed under Korean environmental conditions. The results show that joint can, overlap and marine growth strongly affect the dynamic response and there is a small effect on the natural frequencies of the designed structure. Choosing the appropriate transition piece mass may reduce the extreme loads in the members. This study provides applicable knowledge of the utilization of large-scale offshore wind turbines for intermediate water depths in Korea.