Wind Turbine Platform Research Articles

Design, Development and Commissioning of the Boldrewood Towing Tank – A Decade of Endeavour

The process of design, build and eventual commissioning of the towing tank on the Boldrewood Innovation Campus is described. The design brief required a facility that would have a capability to test models at a commercial scale but that would be effective as teaching environment for the next generation of Naval Architects as well as providing a flexible space for future fundamental research. Each of these provided their own challenges but the eventual solution of a 138 m long, 3.5 m deep, 6 m wide facility has more than met the initial aspirations. Equipped with 12 independent 0.5 m wavemaking flaps at the West end, a passive beach at the East end, a deployable side beach along the South wall for post run wave absorption and a monocoque Aluminium alloy carriage, the Boldrewood towing tank has now been successfully operating for more than a year. The carriage position and speed are controlled by a twin winch arrangement using a laser positioning system and low embodied energy composite cables. The carriage can reach a maximum speed of 10 m/s with controllable acceleration rates and can have up to four constant speed phases per run. Initial commissioning results and comparisons with benchmark data for the KCS hull confirm the accuracy and repeatability of the facility. In particular, the position and speed of the carriage are known to a high level of precision. To date research and consultancy work has spanned the performance of high speed vessels, uncrewed underwater and surface vessels, wave energy and tidal current systems, floating platforms for wind turbines, performance sport work for sailing, kayaking, rowing and swimming, open water propeller tests as well as conventional displacement vessel testing for self-propulsion and resistance. All ship science and maritime engineering students use the facility as part of their taught modules in every year of their programme as well as for individual, MSc and group projects as appropriate. It has also made a strong impact on the many thousands of visitors a year to the campus for science and engineering open days.

Distributed real-time hybrid simulation method for dynamic response evaluation of floating wind turbines

Limited land and near coast spaces led to the development of floating wind turbine (FWT) farms in unlimited space of deep water with steady winds. Experimental evaluation of dynamic responses of FWT is essential to ensure its safe operation. However, due to laboratory limitations and scaling issues, realistic FWT responses are difficult to be replicated on scaled-down test specimens. To facilitate larger-scale testing of FWT and apply realistic wind and wave loads, distributed real-time hybrid simulation (dRTHS) method is proposed which combines the testing of FWT substructures at geographically distributed laboratories using wind tunnels and wave tanks. In this research, dRTHS experimental method for FWT is developed and its feasibility is verified through a series of virtual dRTHS (vdRTHS) and proof-of-the-concept partial dRTHS tests. The equation of motion of a prototype FWT structure under coupled aerodynamic and hydrodynamic loads was partitioned to represent the wind turbine tower and platform substructures, based on which substructural formulation was derived. During the vdRTHS, two distributed real-time controllers were used to simulate the physical testing of the two substructures tested in the wind tunnel and water tank, respectively, with interfacing data being transferred in real-time through a network. FWT responses from vdRTHS match well with those obtained from numerical simulations of the whole FWT model and the substructured models, demonstrating that the feasibility of the proposed dRTHS method. In addition, the substructuring approach, the vdRTHS testing platform, and the method to overcome network communication delay are effective in the vdRTHS resulting in reliable FWT dynamic responses under coupled loading conditions. Furthermore, the proposed dRTHS concept was verified through a partial distributed physical tests during which the wind turbine substructure was tested physically, while the platform substructure and the hydrodynamic loads were simulated numerically.

Design Design and Discussion of Offshore Floating Platforms for Wind Turbines

Alongside the development of human civilisations over the last century, the global demand and consumption of fossil fuels have experienced a significant increase. Consequently, environmentally friendly and sustainable designs are in high demand in every professional field. This report focuses on two designs of floating wind turbine platforms as well as related professional discussions in the field of fluid mechanics.

Dynamic responses and mooring line failure analysis of the fully submersible platform for floating wind turbine under typhoon

The mooring line of the floating platform may fail due to various reasons in long-term service conditions, such as overloading, accidental conditions, and performance deterioration. Combining the advantages of three types of floating offshore wind turbine (FOWT) platforms, i.e., spar type, semi-submersible platform type, and tension-leg platform (TLP) type, a novel fully submersible platform (FSP) with vertical CFRP tendons and circumferential catenary chains was developed. The commercial hydrodynamic software ANSYS-AQWA is used to analyze the dynamic responses and mooring forces of the FSP under different wind speeds. It is assumed that a certain mooring line is disconnected from the platform when its safety factor is smaller than the threshold value. The influence of the mooring line failure on the motion characteristics of the platform and the states of the remaining mooring lines are analyzed. Simulated results show that the failure of mooring lines mainly affects the responses of sway, roll, and yaw, which is closely related to the stiffness and symmetry of the mooring system. Once a mooring line fails abruptly, the equilibrium of the mooring is disturbed and the mooring forces are redistributed, leading to a continuous failure of the same type of mooring on the same side, but the entire structure remains stable without overturning, indicating that the mooring system has good redundancy under extreme conditions.

Hydrostatic stability and hydrodynamics of a floating wind turbine platform integrated with oscillating water columns: A design study

One of the challenges in the installation of Floating Wind Turbines (FWTs) is the occurrence of undesired resonant motions under environmental conditions, which adversely impact their lifespan, maintenance cost, components stress, and electrical performance. This article addresses this challenge by proposing a novel design for the substructure of semisubmersible FWTs, aimed at mitigating the undesired oscillations and improving sustainability. The design concept involves integrating Oscillation Water Columns (OWCs) within the FWT’s substructure, focusing on a specific type of semisubmersible FWT called WINDMOOR. The chambers have been incorporated into the columns, allowing water to enter and compress/decompress the air inside them. The main objective of this article is to demonstrate the feasibility of integrating OWCs into a semi-submersible platform-type FWT. To accomplish this, the adjustment of ballast inside the substructure is performed, followed by evaluations of the system’s intact hydrostatic stability and hydrodynamic performance. Sensitivity analysis has also been conducted to assess the impact of the chamber size on system performance. The results indicate that a chamber size of 4.5 m satisfies the criteria for intact hydrostatic stability without requiring changes to the substructure dimensions. However, increasing the chamber size negatively affects system stability. Furthermore, the hydrodynamic analysis employing Response Amplitude Operators (RAOs) illustrates the effectiveness of integrating OWCs to enhance the stability of this novel hybrid system. This integration results in increased damping effects, which contribute to the reduction of resonant motions in the system’s modes, particularly heave, roll, and pitch. Throughout the article, comprehensive comparisons have been conducted between the WINDMOOR FWT and the proposed hybrid semisubmersible FWT-OWCs system. These comparisons have been performed at every step, including the redesign of the substructure, adjustment of ballast, hydrostatic stability analysis, and hydrodynamic analysis.

A new methodology for upscaling semi-submersible platforms for floating offshore wind turbines

Abstract. This paper presents a new upscaling methodology for semi-submersible floating offshore wind turbine platforms. The size and power rating of offshore wind turbines have been growing in recent years, with modern wind turbines rated at 10–18 MW in contrast with 2–5 MW in 2010. It is not apparent how much further wind turbine size can be increased before it is unjustified. Scaling relations are a useful method for analyzing wind turbine designs to understand the mass, load, and cost increases with size. Scaling relations currently do not exist but are needed for floating offshore platforms to understand how the technical and economic development of floating offshore wind energy may develop with increasing turbine size. In this paper, a hydrodynamic model has been developed to capture the key platform response in pitch. The hydrodynamic model is validated using OpenFAST, a high-fidelity offshore wind turbine simulation software. An upscaling methodology is then applied to two semi-submersible case studies of reference systems (the Offshore Code Comparison Collaboration Continuation (OC4) 5 MW and the International Energy Agency (IEA) 15 MW). For each case study, the platform pitch angle at rated wind turbine thrust is constrained to a specified value. The results show that platform dimensions scale to a factor of 0.75, and the platform steel mass scales to a factor of 1.5 when the wall thickness is kept constant. This study is the first to develop generalized upscaling relations that can be used for other triangular semi-submersible platforms that have three outer columns with the turbine mounted at the center of the system. This is in contrast with other studies that upscale a specific design to a larger power rating. This upscaling methodology provides new insight into trends for semi-submersible platform upscaling as turbine size increases.

Dynamic Behavior Assessment of OC4 Semi-submersible FOWT Platform Through Morison Equation

This paper proposes an effective inertia coefficient (EIC) in the Morison equation for better wave-force calculations. The OC4 semi-submersible floating offshore wind turbine (FOWT) platform was considered to test the feasibility. Large diffraction at large Keulegan– Carpenter (KC) numbers and the interaction between columns can result in errors in estimating the wave force using the Morison equation with a theoretical inertia coefficient, which can be corrected by the EIC as a function of the wave period and direction. The horizontal and vertical wave forces were calculated using the Morison equation and potential theory at each column, wave period, and wave direction. The EICs of each column were then obtained, resulting in a minimal difference between the Morison inertia force and the wave excitation force by the potential theory. The EICs, wave forces, phase angles, and dynamic motions were compared to confirm the feasibility of an EIC concept under regular and random waves.

Research on dynamic response prediction of semi-submersible wind turbine platform in real sea test model based on machine learning

The motion response of floating offshore wind turbine (FOWT) platform is closely related to its safety, and model test is the most direct method to fully study its dynamic characteristic behavior. In this paper the dynamic response of intermediate-scale physical semi-submersible FOWT model test under real sea environmental loads is studied and compared with the numerical model dynamic response, demonstrating that some limitations of small-scale physical model tests can be overcome, such as the catenary effect of mooring lines. It is found that the nonlinear dynamic characteristics of the physical model under actual marine environmental loads can be captured by the numerical model, which can improve the fidelity of model test data for semi-submersible FOWT structures in the existing literature. The dynamic response database of semi-submersible FOWT under complex wind, wave and current loads was established by using a numerical model with high accuracy, and was used in the prediction research of different machine learning algorithm models such as Genetic Algorithm optimization Back Propagation neural network (GA-BP), Support Vector Machine (SVM) and Gaussian Process (GP). The research shows that the relationship between the environmental load and the dynamic response of FOWT can be established by using the machine learning model, in which the number of samples has a significant impact on the prediction of the mooring line tension, and the research on the three algorithm models shows that GP performs significantly better than GA-BP and SVM in predicting the mean value of surge, pitch and mooring line force. For the dynamic response prediction of mooring line tension, GP model can get better results. In the future, this method will become an important method to predict and monitor the dynamic response of FOWT.

Effect of the multi-segment mooring system failure on the dynamic motions of the floating platform

The mooring system can effectively reduce the dynamic response of floating wind turbine platforms (FOWT), especially in extreme environmental conditions. Investigating mooring line failure is crucial for ensuring safety in FOWT operations. MSM-BMW is the multi-segment mooring (MSM) arrangement of the catenary and taut lines, consisting of the buoy multi-clump weight (BMW) that is proposed as a new concept to reduce platform hydrodynamic response. The aim of this study is to assess the performance of FOWTs in both intact and mooring system failure scenarios for two mooring systems: OC4-DeepCwind, representing the primary configuration, and MSM-BMW, representing a hybrid mooring system. The boundary element method (BEM) has been used in the time domain under irregular wave conditions in different wave directions. To simulate mooring line failure, a specific mooring line was intentionally detached from the floating platform at a predetermined time. The hydrodynamic platform responses, mooring line tensions and their statistical responses were checked. Based on the result the BMW concept presents a better performance in both intact and failure modes in comparison primary mooring system (OC4) that significantly reduces platform offset.

Numerical validations and investigation of a semi-submersible floating offshore wind turbine platform interacting with ocean waves using an SPH framework

In this work, we propose numerical validations of the DeepCwind semi-submersible floating platform configuration for a single horizontal axis wind turbine using data from two experimental testing investigations. A Smoothed Particle Hydrodynamics solver is employed to estimate fluid induced loads, whereas the mooring connections are handled via an external library. The first validation setup is based on the DeepCwind offshore wind semi-submersible concept moored with a system of taut-lines and tested for free-decay surge and heave motion (OC6-Phase Ia). The damping evaluation yields a fair estimation of the heave damping behavior, whereas much more dissipation is experienced for the surge. The second validation features a full hydrodynamic characterization of the frequency-related load patterns induced by three different sea-state representations (mono-, bi-chromatic, and irregular waves) (OC6-Phase Ib). The model accurately matches the hydrodynamic load estimation for the whole spectrum of investigated wave components, perfectly capturing the non-linear behavior shown by the considered wave patterns. This work concludes with a systematic study on the motion response, mooring tension, pressure and vorticity, suggesting that: the wave steepness criterion alone cannot identify the most restrictive load case; waves with spectral characteristics close to the heave resonance period lead to higher tensions in the mooring systems, whereas the maximum fluid-induced loads on the hull are decoupled from displacement peaks, showing an average reduction of 30% with respect to the maxima; very steep waves maximize the likelihood of wave overtopping and slamming loads, resulting in locally induced overpressure on the free-board of up to 100% higher than expected for similar wave heights with milder profiles. The input data for these last tests is released for the sake of reproduction.

Power and dynamic performance of a floating multi-functional platform: An experimental study

Hybrid platforms which integrate a floating offshore wind turbine and a wave energy converter are a promising technology as the wave energy converter can lead to a more stable platform and potentially lower costs. In the present work, a semi-submersible floating offshore wind turbine platform integrating with an array of wave energy converters (WECs) in the form of an oscillating water column (OWC) is presented and tested experimentally. The hydrodynamic properties of the multi-functional platform were investigated under a series of regular and irregular wave tests considering both operational and survival sea states. The influence of various parameters (including incident wave directions and chamber opening ratios) on the dynamic responses and the wave energy capturing were systematically studied. The introduction of the oscillating water column can not only capture wave energy but also reduce the heave, roll and pitch responses, especially for long waves kh ≤ 2.0, kh ≤ 1.4 and kh ≤ 1.76 respectively. The maximum reduction in heave, roll and pitch are 35 %, 55.4 % and 13.8 %, respectively. The chamber air orifice size was analyzed and optimized. From the survival sea state tests, it is found that the introduction of the OWC WECs decreases the maximum amplitudes of the platform motions in all five freedoms and the nacelle acceleration.

Variability of Kinetic Response Estimates of Froude Scaled DeepCwind Semisubmersible Platforms Subjected to Wave Loading

Abstract Froude scaling for Floating Offshore Wind Turbine (FOWT) platforms is typical for understanding and interpreting their behavior and subsequent designs for testing in wave basins. Despite its popularity, the variability and uncertainty of the kinetic responses of such floating structures as a function of scaling require more attention. This work addresses the question of consistency of Froude scaling by comparing the hydrodynamic responses of a range of DeepCwind semisubmersible FOWT scaled models (full model, 1/2, 1/4, 1/9, 1/16, 1/25, 1/36, 1/49, and 1/50). The comparison was made both in the mooring-line tension and bending moment of structural members, which are directly related to their safety limit states. Hydrodynamic forces due to diffraction, radiation, and viscosity along with hydrostatic forces and mooring boundaries are modeled by ansys-Aqwa, which were subsequently converted to bending moment estimates. The variability of kinetic responses like mooring-line tensions and bending moment estimates was investigated for each scaled model, along with the identification of regions of inconsistencies. In the context of offshore renewable energy development through technological readiness levels, the study is especially pertinent for understanding how force variabilities and uncertainties are related to these kinetic responses of semisubmersible platforms.

Experimental Validation of Models of a Hull-Based Tuned Mass Damper System for a Semisubmersible Floating Offshore Wind Turbine Platform

Floating offshore wind turbine designs can be further optimized if the controller and remaining systems are designed together, known as control co-design. To effectively perform control co-design, modeling tools predicting the influence of the control systems on the response of a system must be validated. This article presents an experimental validation that utilizes a scale model of a semisubmersible platform for an offshore wind turbine that is fitted with adjustable tuned mass dampers. These dampers can be tuned to attenuate either the hull-pitch resonance or the tower-bending resonance. The data from the experiment are used to validate state-of-the-art modeling tools. It is shown that the models capture the overall effects of the tuned mass dampers; however, some models overpredict the reduction in platform pitch motion when the dampers are tuned to the pitch resonance. The relative reduction in the tower-base bending moment is more consistently captured by the models when the dampers are tuned to the tower-bending resonance. However, there are significant differences in the absolute level of tower-base bending moment between the models and the experiment. Much of the differences observed are a consequence of the challenge with accurately predicting the baseline platform resonance motion and the tower-bending moment, which should be addressed in future modeling efforts.

Application of CFD on VIM of semi-submersible FOWT: A Case Study

This study examines the Vortex Induced Motions (VIM) of the INO WINDMOOR 12 MW semi-submersible Floating Offshore Wind Turbine (FOWT) platform using three-dimensional Computational Fluid Dynamics (CFD). The results from both model- and full-scale simulations are presented. The model scale results reveal varying VIM performances at different current headings, with detailed flow visualizations and analyses of hydrodynamic loads on FOWT components providing insights into the underlying wake interaction scenarios. One simulation shows bifurcated VIM, where regular motions are intermittently interrupted due to simultaneous suppression of vortex shedding on all FOWT columns. Preliminary full-scale CFD results suggest a strong scale effect. The paper concludes with a discussion on how CFD simulation can be more effectively used in VIM research.

Research on the method of digital twin operation and maintenance platform for intelligent early warning of wind turbine tower

Wind power generators have a complex structure and operate in harsh environments, where working conditions are highly variable. As a result, the operation and maintenance of wind turbines face numerous challenges. In response to the need for the development of wind power operation and maintenance informatization, it is necessary to satisfy the requirements for multi-party collaborative monitoring to ensure the long-term safe and reliable operation of wind turbines. In this paper,we proposed a method for building an intelligent early-warning digital twin platform focused on the simulation of wind turbines and tower components. The platform construction method proposed in this article is based on the Web and from the perspective of intelligent operation and maintenance of wind turbines. It establishes a warning model for tower agent simulation and vibration signal time series prediction. The tower mechanism model is established based on the operating data set of a 4MW wind turbine at Shanghai Electric. Different physical responses of the tower under different wind speeds are simulated, and an agent model using LSTM and decision tree models is established for predictive analysis. To account for uncertainty, a Bayesian-LSTM model is established to warn against predictive errors. Finally, a data-driven digital twin wind turbine platform is achieved on the Web.

Dynamic Simulation of Wave Point Absorbers Connected to a Central Floating Platform

AmAmong the challenges currently being faced by the wave energy industry, there are the ones related to the mathematical and numerical modelling of Wave Energy Converters. Because various levels of physical complexity are reflected in the dynamics of wave converters, the mathematical modelling of such systems usually comes up with nonlinear dynamic equations to be solved. The nonlinearities, however, may appear in many ways. In this paper, the nonlinear geometric constraints that arise naturally in hinged structures are investigated for floating multi-body systems including wave point absorbers. To achieve that, a method of constraint linearization is proposed and applied to a realistic case study. The method is based on generalized coordinates and generates a robust first-order dynamic matrix to characterize the multi-degrees of freedom hydrodynamic system. The simulation outputs the motion response for all floating bodies, as well as the constraining forces responses, among other parameters. The method requires knowledge of the geometries of the system but rather few assumptions, namely, to perform the linearization of constraints. The method is illustrated with a case study, where three wave point absorbers are concentrically attached to a Floating Offshore Wind Turbine platform with an onboard hydraulic Power-Take Off system.

NEMOH: Open-source boundary element solver for computation of first- and second-order hydrodynamic loads in the frequency domain

NEMOH is developed to solve potential flow problems using the boundary element method for computing wave loads on offshore structures. The solver solves the first-order problem in the frequency domain. An extended module enables computation of the second-order loads on a structure in bi-chromatic bi-directional waves. NEMOH is released as open-source, developed, and distributed under the terms of GNU General Public License (GPLv3). Along with the source code, a user manual is available which facilitates the compilation and execution of the source files. In this new release, NEMOH v3.0 has new features; irregular frequencies removal method, new linear system solvers for enhancing computational efficiency, and a new module for computing the full quadratic transfer function (QTF) of drift forces. Verification cases are shown for a truncated cylinder, a truncated cylinder with a thin heave plate, a spar buoy platform (SOFTWIND), and a semi-submersible platform (OC4). The results are compared with reference data from commercial software, WAMIT, DIODORE, and HYDROSTAR, and the comparison showed that NEMOH v3.0 is accurate and efficient. Program summaryProgram Title: NEMOHCPC Library link to program files:https://doi.org/10.17632/k9v4hjb5xj.1Developer's repository link:https://gitlab.com/lheea/NemohCode Ocean capsule:https://codeocean.com/capsule/9256007Licensing provisions: GPLv3Programming language: FortranExternal libraries and programs: BLAS [1], LAPACK [2]Nature of problem: NEMOH solves the potential flow problems of diffraction and radiation in wave-structure interactions. Typical use is the estimation of the dynamic response of floating structures, e.g. floating offshore wind turbine platforms, or wave-energy converters.Solution method: The linear potential flow problems, diffraction and radiation, are expressed in the boundary integral of the source distribution formulation. The equations are solved in the frequency domain and implemented using the boundary element method with quadrilateral panels. The source distribution on the body panels is obtained by solving the linear system. The hydrodynamic coefficients are computed with the known source distribution. The second-order potential flow problem is not solved directly; the Green formulation is used with an assisting function which is the instantaneous radiation potential, that allows the computation of second-order force for given first-order hydrodynamic quantities.Additional comments including restrictions and unusual features:•The previous version, NEMOH v2.0 [3], was available only for computing first-order hydrodynamic coefficients without the irregular frequency removal method. NEMOH v3.0 has new features, the extended boundary integral method is implemented for removing the irregular frequencies, new linear system solvers are added for enhancing computational efficiency, and a new module is added for computing second-order wave loads. NEMOH v3.0 has better accuracy than v2.0 due to finer interpolation points of the free-surface Green function and a better integration method for constructing the influence coefficients.•For the free-surface piercing bodies problem, it is known that non-unique solutions exist in the boundary integral equation at certain frequencies. In NEMOH, the extended boundary integral equation is applied to remove the irregular frequencies by providing the lid panels on the body waterplane. The second-order loads require the computation of the free-surface forcing terms in the integral forms. These free-surface integrals are essential for the sum-frequency wave loads but may be negligible in the difference-frequency loads. For now, it is suggested not to apply the lid panels when the free-surface integrals are computed.

Reliability-based design method for marine structures combining topology, shape, and size optimization

The uncertainty and extremity of ocean conditions make the design of marine structures a challenging process. Reliability-based optimization is a powerful approach to enhance material utilization and ensure system survivability. In this paper, a novel reliability-based design optimization (RBDO) method that combines topology, shape, and size optimization is proposed to achieve the design of marine structures. Within the framework of decoupled sequence optimization and reliability assessment, the developed method employs an innovative multi-technology combined optimization Scheme and a new reliability assessment algorithm. The combined optimization Scheme is established by simultaneously incorporating topology, shape, and size optimization technologies to further improve the lightweighting effect. The advanced arc interpolation algorithm is developed, which dynamically selects the advanced mean value method or arc interpolation method based on the trend judgment criterion to accelerate the calculation for the most probable point in reliability assessments. The RBDO examples of the wind turbine jacket and platform stiffened plate are utilized to verify the proposed method's applicability and validity, and the results are compared with those of other approaches. The findings prove that this RBDO method can effectively address reliability-based design problems of marine structures and is superior in providing lightweighting structures compared with others.

The dynamic response of floating offshore wind turbine platform in wave–current condition

In this paper, the fluid–structure interaction of floating offshore wind turbine (FOWT) platforms under complex ocean conditions is investigated using OpenFOAM and in-house developed models. Two types of FOWT platform, i.e., a semi-submersible platform and a barge platform, are studied for their dynamic responses to either wave or current. The results reveal that a semi-submersible platform exhibits larger cross-flow motion and lock-in phenomenon, while a barge platform experiences smaller motion with no significant lock-in within the velocity range examined. The combined wave–current conditions are further studied for the semi-submersible platform, with different angles between wave and current, the current speeds, and wave parameters. Unlike other investigations focusing on colinear wave–current interaction, in which the waves usually mitigate vortex-induced motion (VIM); here, we find that waves might lead to an enhanced VIM with a large angle between current and wave. The evaluation on the interaction effect factor shows that the largest wave height in the lock-in region does not lead to the most dangerous scenario, herein, the largest platform motion. Instead, a smaller wave height with a large wave period can induce even larger motion.

Numerical investigation on wake characteristics of floating offshore wind turbine under pitch motion

AbstractThe floating offshore wind turbine platform is subject to six degrees‐of‐freedom motions due to the influence of wind, waves, and currents. To examine the impact of pitch motion on the wake characteristics of offshore wind turbines, this research focused on investigating the wind turbine wake under pitch motion using the RANS model and the overset grid technique based on OpenFOAM. The simulation accounted for wind shear flow conditions and simplified the movements of the six degrees‐of‐freedom of floating platform. Results showed that the wind turbine wake recovery rate increased with pitch motion, and that the recovery rate increased with the frequency and amplitude of the pitch motion. The wind velocity recovery rate of near‐wake was sensitive to small amplitudes, while the far‐field wake was unaffected. When the amplitude was larger, pitch motion accelerated the wind velocity recovery rate in all wake areas, leading to more pronounced diffusion. These findings provide insight into the mechanism of wake generation and diffusion under pitch motion in floating offshore wind turbines and offer a basis for enhancing the wake deficit model of floating offshore wind farms.