Research Of Dynamic Response Of Detachable Floating Wind Turbine-Aquaculture Cage Composite Structure

In recent years,in order to develop the vast amount of wind energy resources in the deep sea and alleviate the problems of sea water pollution and production limitation caused by offshore aquaculture,people began to combine the large floating wind turbine and aquaculture cage to realize the comprehensive utilization of wind energy and fishery resources.In this paper,the wind turbine is combined with the aquaculture cage through the connector,and a detachable composite structure is designed to reduce the integrated installation cost,and the aquaculture cage can also be re-installed for the wind turbine in service to improve the utilization rate of resources.The main research contents are as follows:(1)Composite structure design of detachable aquaculture cage and floating wind turbine.Using DTU 10 MW offshore three float bowl floating wind turbine,a compound structure of aquaculture cage and floating wind turbine was designed by referring to the design cases and standards of aquaculture cage and connector,and the detachable connector was designed.The wind-wave-current loads of the structure under normal and self-existing conditions were calculated and analyzed.The stress of the composite structure,the displacement of the tower top and the stress of the connector were calculated by using the finite element software.The strength of the composite structure was checked and the stability of the composite structure was analyzed.(2)Dynamic response analysis of floating wind turbine-aquaculture cage complex structure.The structural hydrodynamic model was established by ANSYS AQWA software,and the hydrodynamic-aerodynamic-servo-elastic fully coupled model was established by OPENFAST software.Firstly,the dynamic response of NREL 5MW floating wind turbine was analyzed,and the correctness of the numerical model was verified by comparing with the shrinkage experiment results.Then,the hydrodynamic model of wind turbine-aquaculture cage was established based on DTU 10 MW floating wind turbine,and the composite structure was analyzed in the frequency domain combining Morison equation and Three-dimensional potential flow theory.The threedimensional parameters and hydrodynamic parameters of the composite structure were input into the Hydrodynamic module of OPENFAST,and the dynamic response in the time domain was analyzed based on the global coupling theory.(3)Optimization design of cage geometry based on dynamic response analysis.The influence of different sizes of steel tube and mesh clothing on dynamic response of composite structure was studied.The compound structure models of 1m,1.3m and 1.6m steel pipe sizes and 2m,3m and 4m net clothing widths were established to study the dynamic response changes in frequency domain and time domain of aquaculture cage and floating wind turbine.Finally,an appropriate geometric size was selected as the reference size.