Effect of heave plates on hydrodynamic response of a spar-type floating offshore wind turbine

摘要

Floating offshore wind turbines (FOWT) are designed for harnessing offshore wind power from deep ocean water locations. The dynamic interactions between the various components of a floating wind turbine are very important in the design of such structures. The spar-type floaters for floating offshore wind turbines have received wide popularity in recent times. In the case of spar-type offshore oil platforms, heave plates are often used in order to limit the heave response of the structure, especially for long waves. The effect of heave plates for such structures are two folds; they increase the added mass and the damping of the structure. However, the feasibility of using heave plates for FOWT structures has not been intensively studied so far. For the present study, the OC3-Hywind spar designed with a 5MW National Renewable Energy Laboratory (NREL) wind turbine is used. A coupled aero-turbine-floater-mooring analysis of the FOWT structure is carried out using the HydroD-HAWC2 model in order to study the effect of heave plates on the hydrodynamic motion. A heave plate in the form of a circular disk attached to the keel of the spar is studied for different diameters of the disks. The Effective response amplitude operators (RAO) of the FOWT are obtained for different disk configurations. Based on the results, recommendations are made on the use of heave plates for FOWT structures. Further, the hydrodynamic response analysis of the wind turbine with heave plate is performed for an operating environmental condition.