Calculation Of The Wave Loads On Offshore Wind Turbines

The offshore wind farms possess rich wind energy resources that are characterized by higher annual average wind speed,lower turbulence intensity and minor wind shear effect when compared to the on-land wind energy resources.Nevertheless,unsteady hydrodynamic loads on the support structure caused by complex ocean waves and currents have severe impacts on the aerodynamic performance of the whole wind turbine system.Detailed simulations of the wave loads on a single pile support structure have been carried out using both the numerical wave tank method and the Morison method to better understanding the mechanism of the interactions between the waves and the support structure of the offshore wind turbineFirst,the Morison method is used to calculate the dynamic wave loads on the support structures of the offshore wind turbine.Ocean waves are modelled using linear superposition method based on the wave spectrum,and the wave loads can be obtained through wave mechanism analysis using the Morison method.A numerical wave tank is built based on incompressible unsteady solver of ANSYS-Fluent software.The free surface of the wave motion is captured using VOF model,and the wave is then generated and eliminated using UDF module combined with the dynamic mesh technology.Comprehensive numerical investigations are conducted to simulate the dynamic loads on the support structure of an offshore wind turbine and the interactions between the waves and support structure using the three-dimensional numerical wave tank method.It can be observed that the results from both the Morison method and numerical wave tank agree well with the experimental data.The Morison method can give a good prediction on the loads with its advantage in efficiency.Meanwhile,the numerical wave tank method can provide more detailed field information of the multiphase flow,and can be applied in the numerical estimations of wave loads on complex support structures.