Predicting loads and dynamic responses of an offshore wind turbine in a nonlinear mixed sea

Abstract

ABSTRACT In this article the loads and dynamic responses of an offshore wind turbine (OWT) operating in a nonlinear multidirectional mixed sea have been rigorously investigated. It has been demonstrated that nonlinearly simulated realistic waves with bottom effects should be utilised as inputs in the stochastic time domain simulation in order to design an un-conservative support structure for the offshore wind turbine. In order to further improve the simulation efficiency, a novel transformed linear simulation method based on a Hermite transformation model has been first proposed in this article for generating equivalent waves as those obtained from the nonlinear simulation method. The predicted results of the loads and dynamic responses of the offshore wind turbine have been rigorously analysed and systematically compared, and the advantages of using our proposed novel method have been convincingly substantiated.