&nbsp; &nbsp; Although the technology of floating offshore wind turbines (FOWTs) is rapidly moving forward, there is still a long way to go for the commercial application due to weak economic competitiveness. Recently, a novel structure integrating a floating offshore wind turbine with a steel fish farming cage (FOWT-SFFC) has been developed by two leading authors to enhance the competitiveness of FOWTs. This work is dedicated to comparing the experimental and numerical results of the dynamic responses of FOWT-SFFC under wind and wave loadings.&nbsp; &nbsp; The experimental study is carried out in the Ocean Basin of Tsinghua Shenzhen International graduate school, with Froude scaling of 1:30 chosen for the fabrication of the physical model. The basin owns a wind generator that is capable of generating high-quality wind fields, including steady and random wind. A small commercial wind turbine is used to produce the scaled wind loads on FOWT-SFFC in terms of the similarity of thrust force.&nbsp; &nbsp; In this paper, the setup of model tests is described first. Second, the experimental results of FOWT-SFFC under a variety of load cases are presented. They include free decay tests of tower and substructure, seakeeping tests for hydrodynamic motion RAOs (Response Amplitude Operators), and dynamic responses corresponding to normal operating and survival conditions. The experimental data highlights the outstanding performance of FOWT-SFFC to withstand harsh environments. Finally, for validation purposes, a numerical model of FOWT-SFFC is built in the software OrcaFlex. The numerical simulation results are compared with the experimental results. It is shown that they agree well in most of load cases, not only validating the use of Froude scaling and associated model setup in experiments, but also revealing increased damping in the presence of fish nets. Furthermore, even though a number of nonlinearities do exist in aerodynamic and hydrodynamic loads, the structural responses tend to be Gaussian.

Dynamic Responses of the State-of-the-Art Floating System Integrating a Wind Turbine With a Steel Fish Farming Cage: Model Tests vs. Numerical Simulations

Paper Proceedings: https://asmedigitalcollection.asme.org/OMAE/OMAE2021/volume/85116

OMAE 2021

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