The impact of passive tuned mass dampers and wind–wave misalignment on offshore wind turbine loads

2014 ◽  
Vol 73 ◽  
pp. 54-61 ◽  
Author(s):  
Gordon M. Stewart ◽  
Matthew A. Lackner
Keyword(s):  
Wind Turbine ◽  
Wind Wave ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Tuned Mass Dampers ◽  
The Impact

scholarly journals Effects of Wind-Wave Misalignment on a Wind Turbine Blade Mating Process: Impact Velocities, Blade Root Damages and Structural SafetyAssessment

2020 ◽  
Vol 19 (2) ◽  
pp. 218-233
Author(s):  
Amrit Shankar Verma ◽  
Zhiyu Jiang ◽  
Zhengru Ren ◽  
Zhen Gao ◽  
Nils Petter Vedvik
Keyword(s):  
Wind Turbine ◽  
Failure Modes ◽  
Wind Wave ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Alignment Procedure ◽  
Blade Root ◽  
Wave Conditions ◽  
The Impact ◽  
Relative Motions

Abstract Most wind turbine blades are assembled piece-by-piece onto the hub of a monopile-type offshore wind turbine using jack-up crane vessels. Despite the stable foundation of the lifting cranes, the mating process exhibits substantial relative responses amidst blade root and hub. These relative motions are combined effects of wave-induced monopile motions and wind-induced blade root motions, which can cause impact loads at the blade root’s guide pin in the course of alignment procedure. Environmental parameters including the wind-wave misalignments play an important role for the safety of the installation tasks and govern the impact scenarios. The present study investigates the effects of wind-wave misalignments on the blade root mating process on a monopile-type offshore wind turbine. The dynamic responses including the impact velocities between root and hub in selected wind-wave misalignment conditions are investigated using multibody simulations. Furthermore, based on a finite element study, different impact-induced failure modes at the blade root for sideways and head-on impact scenarios, developed due to wind-wave misalignment conditions, are investigated. Finally, based on extreme value analyses of critical responses, safe domain for the mating task under different wind-wave misalignments is compared. The results show that although misaligned wind-wave conditions develop substantial relative motions between root and hub, aligned wind-wave conditions induce largest impact velocities and develop critical failure modes at a relatively low threshold velocity of impact.

Coupled Dynamic Response of a Spar Type Floating Offshore Wind Turbine

2014 ◽  
Author(s):  
Cheng Peng ◽  
Fasuo Yan ◽  
Jun Zhang
Keyword(s):  
Numerical Simulation ◽  
Wind Turbine ◽  
Wind Wave ◽  
Offshore Wind ◽  
Numerical Code ◽  
Offshore Wind Turbine ◽  
Mooring System ◽  
Floating Offshore Wind Turbine ◽  
The Impact ◽  
Near Future

FOWTs (Floating Offshore Wind Turbine) are feasible renewable devices to harness the wind energy in the near future. However, because of the complicated interactions among wind turbine, mooring system and the hull, the motion of a FOWT under the impact of severe wind, wave and current has not been well studied yet. This research focuses on the coupled numerical analysis of a FOWT. A numerical code COUPLE-FAST is developed by integrating two existing codes, namely, COUPLE and FAST, to carry out the task. In this study, a particular FOWT model is chosen for the numerical simulation, which consists of a NREL 5-MW baseline wind turbine and OC3-Hywind Spar. Although the numerical simulation is limited to this particular type of FOWTs, the results and related code (COUPLE-FAST) may be helpful to the design of FOWTs in the future.

Model Test and Numerical Analysis of an Offshore Bottom Fixed Pentapod Wind Turbine Under Seismic Loads

2016 ◽  
Author(s):  
Wenhua Wang ◽  
Zhen Gao ◽  
Xin Li ◽  
Torgeir Moan ◽  
Bin Wang
Keyword(s):  
Wind Turbine ◽  
Wind Wave ◽  
Seismic Analysis ◽  
Wind Farms ◽  
Dynamic Responses ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Test Model ◽  
Structural Dynamic ◽  
Load Conditions

In the last decade the wind energy industry has developed rapidly in China, especially offshore. For a water depth less than 20m, monopile and multi-pile substructures (tripod, pentapod) are applied widely in offshore wind farms. Some wind farms in China are located in high seismicity regions, thus, the earthquake load may become the dominant load for offshore wind turbines. This paper deals with the seismic behavior of an offshore wind turbine (OWT) consisting of the NREL 5MW baseline wind turbine, a pentapod substructure and a pile foundation of a real offshore wind turbine in China. A test model of the OWT is designed based on the hydro-elastic similarity. Test cases of different load combinations are performed with the environmental conditions generated by the Joint Earthquake, Wave and Current Simulation System and the Simple Wind Field Generation System at Dalian University of Technology, China, in order to investigate the structural dynamic responses under different load conditions. In the tests, a circular disk is used to model the rotor-nacelle system, and a force gauge is fixed at the center of the disk to measure the wind forces during the tests. A series of accelerometers are arranged along the model tower and the pentapod piles, and strain gauges glued on the substructure members are intended to measure the structural dynamic responses. A finite element model of the complete wind turbine is also established in order to compare the theoretical results with the test data. The hydro-elastic similarity is validated based on the comparison of the measured dynamic characteristics and the results of the prototype modal analysis. The numerical results agree well with the experimental data. Based on the comparisons of the results, the effect of the wind and sea loads on the structural responses subjected to seismic is demonstrated, especially the influence on the global response of the structure. It is seen that the effect of the combined seismic, wind, wave and current load conditions can not be simply superimposed. Hence the interaction effect in the seismic analysis should be considered when the wind, wave and current loads have a non-negligible effect.

A Numerical Prediction on the Transient Response of a Spar-Type Floating Offshore Wind Turbine in Freak Waves

2020 ◽  
Vol 142 (6) ◽  
Author(s):  
Yan Li ◽  
Xiaoqi Qu ◽  
Liqin Liu ◽  
Peng Xie ◽  
Tianchang Yin ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Wind Turbine ◽  
Offshore Wind ◽  
Numerical Code ◽  
Modulation Method ◽  
Offshore Wind Turbine ◽  
Freak Waves ◽  
Freak Wave ◽  
Floating Offshore Wind Turbine ◽  
The Impact

Abstract Simulations are conducted in time domain to investigate the dynamic response of a spar-type floating offshore wind turbine (FOWT) under the freak wave scenarios. Toward this end, a coupled aero-hydro-mooring in-house numerical code is adopted to perform the simulations. The methodology includes a blade-element-momentum (BEM) model for simulating the aerodynamic loads, a nonlinear model for simulating the hydrodynamic loads, a nonlinear restoring model of Spar buoy, and a nonlinear algorithm for simulating the mooring cables. The OC3 Hywind spar-type FOWT is adopted as an example to study the dynamic response under the freak wave conditions, meanwhile the time series of freak waves are generated using the random frequency components selection phase modulation method. The motion of platform, the tension applied on the mooring lines, and the power generation performance are documented in several cases. According to the simulations, it is indicated that when a freak wave acts on the FOWT, the transient motion of the FOWT is induced in all degrees-of-freedom, as well as the produced power decreases rapidly. Furthermore, the impact of freak wave parameters on the motion of FOWT is discussed.

scholarly journals Effect of Wind Turbulence on Extreme Load Analysis of an Offshore Wind Turbine

2019 ◽  
Author(s):  
Xiaolu Chen ◽  
Zhiyu Jiang ◽  
Qinyuan Li ◽  
Ye Li
Keyword(s):  
Wind Turbine ◽  
Turbulence Intensity ◽  
Environmental Conditions ◽  
Dynamic Responses ◽  
Offshore Wind ◽  
Contour Method ◽  
Offshore Wind Turbine ◽  
Extreme Response ◽  
Wind Turbulence ◽  
The Impact

Abstract Evaluation of dynamic responses under extreme environmental conditions is important for the structural design of offshore wind turbines. Previously, a modified environmental contour method has been proposed to estimate extreme responses. In the method, the joint distribution of environmental variables near the cut-out wind speed is used to derive the critical environmental conditions for a specified return period, and the turbulence intensity (TI) of wind is assumed to be a deterministic value. To address more realistic wind conditions, this paper considers the turbulence intensity as a stochastic variable and investigates the impact on the modified environmental contour. Aerodynamic simulations are run over a range of mean wind speeds at the hub height from 9–25 m/s and turbulence levels between 9%–15%. Dynamic responses of a monopile offshore wind turbine under extreme conditions were studied, and the importance of considering the uncertainties associated with wind turbulence is highlighted. A case of evaluating the extreme response for 50-year environmental contour is given as an example of including TI as an extra variant in environmental contour method. The result is compared with traditional method in which TI is set as a constant of 15%. It shows that taking TI into consideration based on probabilistic method produces a lower extreme response prediction.

scholarly journals EXPERIMENTAL STUDY ON THE LOADING AND SCOUR OF THE JACKET TYPE OFFSHORE WIND TURBINE FOUNDATION

2011 ◽  
Vol 1 (32) ◽  
pp. 25
Author(s):  
Ray-Yeng Yang ◽  
Hsin-Hung Chen ◽  
Hwung-Hweng Hwung ◽  
Wen-Pin Jiang ◽  
Nian-Tzu Wu
Keyword(s):  
Wind Turbine ◽  
Water Depth ◽  
Fixed Bed ◽  
Offshore Wind ◽  
Scale Model ◽  
Offshore Wind Turbine ◽  
Wave Flume ◽  
Wave Basin ◽  
Scour Protection ◽  
The Impact

A 1:36 scale model tests were carried out in the Medium Wave Flume (MWF) and Near-shore Wave Basin (NSWB) at the Tainan Hydraulics Laboratory (THL) with the jacket type offshore wind turbine foundation located in the test area. The loading of typhoon wave with current on the jacket type offshore wind turbine foundation was investigated in the MWF with fixed bed experiment. Meanwhile, the scour around the jacket type offshore wind turbine foundation exposed to wave and current was conducted in the NSWB with the moveable bed experiment. Two locations (water depth 12m and 16m) of the foundations are separately simulated in this study. Based on the analysis from the former NSWB experimental results, the suitable scour protection of a four-layer work around the foundation is also proposed to the impact of scour. Finally, a four-layer scour protection is tested and found to be effective in preventing scour around jacket type foundation of offshore wind turbines at water depth 12m and 16m.

scholarly journals Application of adaptive fuzzy control to suppression vibration response of floating offshore wind turbine

2021 ◽  
Vol 39 (2) ◽  
pp. 241-248
Author(s):  
Jiajia Yang ◽  
Erming He ◽  
Juncheng Shu
Keyword(s):  
Wind Turbine ◽  
Control Strategy ◽  
Passive Control ◽  
Wind Wave ◽  
Fuzzy Controller ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Structural Parameter ◽  
Floating Offshore Wind Turbine ◽  
Adaptive Fuzzy

Floating offshore wind turbine is a complex rigid-flexible coupling nonlinear system, and the accurate dynamic model is difficultly established. Therefore, the wind-wave interference cannot be improved by adopting the conventional control strategy. In order to solve this problem, an adaptive fuzzy controller (AFC) is used to suppress the dynamic response of floating wind turbine. Two correction factors are introduced to optimize the fuzzy rule, and the traditional fuzzy controller (FC) is firstly obtained. Since the balance positions change and structural parameter perturbation of the wind turbine, an AFC is designed and validated. Finally, the suppression vibration responses ability of floating offshore wind turbine by using the different control strategies is studied under the random wind-wave disturbance and blade pitch control system coupling effect. The simulation results show that the tracking ability of the AFC to the target value is obviously higher than that of the FC; Comparing with the passive control strategy, the suppression vibration effect on the power spectral density (PSD) of the platform pitch (PFPI) motion peak can increase by 39.06% by adopting the AFC.

Assessing the Impact of Integrating Energy Storage on the Dynamic Response of a Spar-Type Floating Wind Turbine

2019 ◽  
Author(s):  
Charise Cutajar ◽  
Tonio Sant ◽  
Robert N. Farrugia ◽  
Daniel Buhagiar
Keyword(s):  
Energy Storage ◽  
Dynamic Response ◽  
Wind Turbine ◽  
Energy Demand ◽  
Large Scale ◽  
Preliminary Investigation ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Floating Wind Turbine ◽  
The Impact

Abstract Offshore wind technology is at the forefront of exploiting renewable energy at sea. The latest innovations in the field comprise floating wind turbines deployed in deep waters that are capable of intercepting the stronger, less turbulent winds farther away from the landmass. Despite being able to augment the power harnessed, wind resources remain intermittent in nature, and so unable to satisfy the energy demand at all times. Energy storage systems (ESS) are therefore being considered a key component to smoothen out the supply-demand mismatch when wind penetration into electricity grids increases. Yet, multiple issues pertaining to the integration of ESSs on large-scale projects arise, including economic, environmental and safety considerations. This paper presents a novel concept for integrating a hydro-pneumatic energy storage (HPES) system within a spar-type floating offshore wind turbine (FOWT) platform. It aims to assess the technical feasibility of integrating the storage unit within the floater. A preliminary investigation on the influence of integrated storage on the static stability and hydrostatic response of a conventional ballast-stabilised FOWT is conducted, followed by numerical simulations for the dynamic response using ANSYS® AQWA™. Based on the results presented, several conclusions are drawn on the implications of integrating energy storage with floating wind turbine structures. Finally, a preliminary assessment of the thermal efficiency of the storage system based on this specific embodiment is also presented and discussed.

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