Wave loads on monopile-supported offshore wind turbines: current methods and future challenges

This chapter provides an overview of the methods recently proposed for the prediction of the wave loads on fixed-bottom wind turbines, with particular emphasis on the role of nonlinear wave contributions in the assessment of the dynamic response of the support structure. After a brief presentation of the common numerical approaches to the simulation of OWTs, we review the fundamental equations governing the wave motions, briefly present a numerical method for the numerical solution of the fully nonlinear (FNL) problem and finally summarize the main commonly used analytical wave theories. The available hydrodynamic loading models are discussed, and an overview of the main literature findings and open issues in modelling the nonlinear resonant effects follows. Some key examples of the effects of highly nonlinear waves on the response of a 5-MW OWT are given and finally, a conclusion summarizes the current situation and future trends.