Search

Flow-induce motions (FIM) small-scale model tests were performed for the Jappaku floating offshore wind turbines (JPK), a FOWT developed to operate in Brazilian waters. This paper aims to investigate the presence of FIM on the JPK to show the importance of heave plate (HP) design and to show how HP mitigates FIM. Three different HP dimensions were tested and compared with the condition without HP. In addition, two different incidence angles of the current were tested, namely, 0 deg and 180 deg. The results showed amplitudes in the transverse direction similar to the diameter of the external platform column for the case without HP. These amplitudes are higher than the ones observed for previous deep-draft semi-submersibles found in the literature. Conversely, the largest HP dimensions implied in mitigation of the FIM amplitudes, i.e., very low amplitudes, were observed. The presence of the central column played an essential role in FIM and significantly modified the amplitudes in different current incidences. Due to the different diameters of the external and central columns, the FIM presented two different branches of response related to the vortex-shedding frequency around the columns. The results showed that significant FIM could occur for this specific JPK investigation even with HP. The HP design has a positive effect on reducing dynamic behaviors due to the wave and current incidences. Therefore, its design must be included in the preliminary stages of FOWT developments. [ABSTRACT FROM AUTHOR]

Operations and installation on offshore wind and especially floating are complex and difficult actions due to site accessibility and equipment availability. In this regard, digitalization is disrupting the wind section thanks to the development of advanced sensors, automated equipment, computational power, among other. All these allow to optimize and simplify different parts of the offshore wind power plant development (i.e. design, planning, installation, O&M, etc.). This fact is of special interest on maintenance, since the early detection of failures or malfunctions lead to reduced costly corrective maintenance. This paper presents a literature review of current state-of-the-art on the application of digitalization activities which can be applied for floating wind, including typical component failures, monitoring techniques and advanced digital tools as Digital Twin concept and Building Information Models (BIM). Finally, the review paper provides an analysis of existing gaps, needs and challenges of the sector to provide guides on research and innovation to foster offshore wind sector.

Flow-induced motions (FIM) are an issue for floating offshore structures, such as multi-column platforms, as the phenomenon can decrease the fatigue life of the mooring, riser, and cable systems. The new concept of floating offshore wind turbines (FOWT) have a multi-column design that may be subjected to FIM. In the past, FIM was studied mainly for Oil & Gas platforms installed in deep waters. However, the FIM phenomenon of FOWT has been insufficiently explored. To rectify this, model tests were performed for the semisubmersible (SS) floating system design developed for the DeepCwind project (Offshore Code Comparison Collaboration Continuation (OC4) phase II). This paper will investigate the presence of FIM and show its importance in the design process of FOWT. Three different incidence angles of the current were tested, namely, 0, 90, and 180 deg. For each heading, 30 reduced velocities were tested, across the range 8000 < Re < 70,000. The results showed amplitudes in the transverse direction of around 70% of the diameter of the platform column, which is similar to those observed for deep-draft (DD) SS with circular columns. Note that these amplitude values are larger for a floater with a circular column, than for a platform with square columns. The results showed that as FIM occurred for this specific FOWT SS, its effect has to be considered in the mooring system and electric cable design. [ABSTRACT FROM AUTHOR]

Floating offshore wind turbines (FOWTs) still face many challenges on how to better predict the dynamic responses. Artificial intelligence (AI) brings a new solution to overcome these challenges with intelligent strategies. A new AI technology-based method, named SADA, is proposed in this paper for the prediction of dynamic responses of FOWTs. Firstly, the methodology of SADA is introduced with the selection of Key Disciplinary Parameters (KDPs). The AI module in SADA was built in a coupled aero-hydro-servo-elastic in-house program DARwind and the policy decision is provided by the machine learning algorithms deep deterministic policy gradient (DDPG). Secondly, a set of basin experimental results of a Hywind Spar-type FOWT were employed to train the AI module. SADA weights KDPs by DDPG algorithms' actor network and changes their values according to the training feedback of 6DOF motions of Hywind platform through comparing the DARwind simulation results and that of experimental data. Many other dynamic responses that cannot be measured in basin experiment could be predicted in higher accuracy with this intelligent DARwind. Finally, the case study of SADA method was conducted and the results demonstrated that the mean values of the platform's motions can be predicted by AI-based DARwind with higher accuracy, for example the maximum error of surge motion is reduced by 21%. This proposed SADA method takes advantage of numerical-experimental method and the machine learning method, which brings a new and promising solution for overcoming the handicap impeding direct use of traditional basin experimental technology in FOWTs design.

Considerable efforts are being made worldwide to develop offshore wind energy, both in shallow and deep waters, where bottom fixed solutions are still dominating. Development and successful implementation of offshore floating wind will depend on reducing costs in all areas including design, manufacturing, installation, and operation. Two important cost drivers are manufacturing and installation of the anchoring system. This paper discusses the application of dynamically installed anchors for floating offshore wind turbines. Based on experience from field and model tests, a detailed description of the different aspects of anchor design is presented. At the example of a recently installed floating offshore wind farm, the advantages of the proposed concept are demonstrated. Further cost reduction is achieved by the presented and discussed shared anchoring system. • Dynamically installed anchors for use in floating offshore wind farms. • Anchor sharing using gravity-installed anchors in floating offshore wind farms. • Dynamically installed anchors can reduce the costs of floating offshore wind farms. [ABSTRACT FROM AUTHOR]

Over the past decade, there has been rapid increase in the offshore wind turbine installations. The future installations will see a progression from shallow to deep waters. It necessitates the development of innovative floating platforms to support the offshore wind turbines capable of resisting coupled wind and wave forces to meet the exponential growth of energy demand. The floating offshore wind turbine (FOWT) is a complex dynamic system. There exists coupling and interaction between aerodynamics, hydrodynamics, servodynamics, structural dynamics and mooring dynamics. Various analysis methods have been developed over the time to model the complex behaviour of FOWT system and to accurately predict its response. These methods can be classified as uncoupled, partially coupled and fully coupled methods based on their degree of coupling. Each of these methods can be utilized in the specific stages of the design. This paper provides an integrated review of the recent advances in the experimental and numerical methods used for the dynamic analysis of the FOWT. Various software tools used for the numerical analysis of FOWT are also reviewed in this paper. Fully coupled experimental analysis is usually carried out using real-time hybrid simulation (RTHS) in the laboratory environment. Several possible configurations of RTHS based on different partitioning schemes are also discussed. This paper encapsulates the different methods available in the literature and will be useful for further building up the research in the analysis of FOWTs. Finally, this paper is complemented with the technical challenges and future scope identified based on the review. • Analysis and design specifications for FOWT • Methods for evaluation of hydrodynamic and aerodynamic loads on FOWT • Uncoupled, partially coupled, fully coupled dynamic analysis of FOWT • Real Time Hybrid Simulation and control methods of FOWT • Technical challenges and future scope of FOWT [ABSTRACT FROM AUTHOR]

Hydrodynamic analyses of classic and truss spar platforms for floating offshore wind turbines (FOWTs) were performed in the frequency domain, by considering coupling effects of the structure and its mooring system. Based on the Morison equation and Diffraction theory, different wave loads over various frequency ranges and underlying hydrodynamic equations were calculated. Then, Response Amplitude Operators (RAOs) of 6 DOF motions were obtained through the coupled hydrodynamic frequency domain analysis of classic and truss spar-type FOWTs. Truss spar platform had better heave motion performance and less weight than classic spar, while the hydrostatic stability did not show much difference between the two spar platforms. [ABSTRACT FROM AUTHOR]

The platform and floating structure of spar type offshore wind turbine systems should be designed in order for the 6-DOF motions to be minimized, considering diverse loading environments such as the ocean wave, wind, and current conditions. The objective of this study is to optimally design the platform and substructure of a 3MW spar type wind turbine system with the maximum postural stability in 6-DOF motions as well as the minimum material cost. Therefore, design variables of the platform and substructure were first determined and then optimized by a hydrodynamic analysis. For the hydrodynamic analysis, the body weight of the system was considered, and the ocean wave conditions were quantified to the wave forces using the Morison\'s equation. Moreover, the minimal number of computation analysis models was generated by the Design of Experiments (DOE), and the design variables of the platform and substructure were finally optimized by using a genetic algorithm with a neural network approximation. [ABSTRACT FROM AUTHOR]