Dynamic response and viscous effect analysis of a TLP-type floating wind turbine using a coupled aero-hydro-mooring dynamic code

Recently, wind turbine has been developed from onshore area to offshore area because of more powerful available wind energy in ocean area and more distant and less harmful noise coming from turbine. As it is approaching toward deeper water depth, the dynamic response of the large floating wind turbine experiencing various environmental loads becomes more challenge. For examples, as the structural size gets larger, the dynamic interaction between the flexible bodies such as blades, tower and catenary mooring-lines become more profound, and the dynamic behaviors such as structural inertia and hydrodynamic force of the mooring-line get more obvious. In this paper, the dynamic response of a 5MW floating wind turbine undergoing different ocean waves is examined by our FEM approach in which the dynamic behaviors of the catenary mooring-line are involved and the integrated system including flexible multi-bodies such as blades, tower, spar platform and catenaries can be considered. Firstly, the nonlinear dynamic model of the integrated wind turbine is developed. Different from the traditional static restoring force, the dynamic restoring force is analyzed based on our 3d curved flexible beam approach where the structural curvature changes with its spatial position and the time in terms of vector equations. And, the modified finite element simulation is used to model a flexible and moving catenary of which the hydrodynamic load depending on the mooring-line’s motion is considered. Then, the nonlinear dynamic governing equations is numerically solved by using Newmark-Beta method. Based on our numerical simulations, the influences of the dynamic behaviors of the catenary mooring-line on its restoring performance are presented. The dynamic responses of the floating wind turbine, e.g. the displacement of the spar and top tower and the dynamic tension of the catenary, undergoing various ocean waves, are examined. The dynamic coupling between different spar motions, i.e. surge and pitch, are discussed too. Our numerical results show: the dynamic behaviors of mooring-line may significantly increase the top tension, particularly, the peak-trough tension gap of snap tension may be more than 9 times larger than the quasi-static result. When the wave frequency is much higher than the system, the dynamic effects of the mooring system will accelerate the decay of transient items of the dynamic response; when the wave frequency and the system frequency are close to each other, the displacement of the spar significantly reduces by around 26%. Under regular wave condition, the coupling between the surge and pitch motions are not obvious; but under extreme condition, pitch motion may get about 20% smaller than that without consideration of the coupling between the surge and pitch motions.

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Coupled dynamic response analysis of a multi-column tension-leg-type floating wind turbine

China Ocean Engineering ◽

10.1007/s13344-016-0031-9 ◽

2016 ◽

Vol 30 (4) ◽

pp. 505-520 ◽

Cited By ~ 8

Author(s):

Yong-sheng Zhao ◽

Jian-min Yang ◽

Yan-ping He ◽

Min-tong Gu

Keyword(s):

Dynamic Response ◽

Wind Turbine ◽

Response Analysis ◽

Dynamic Response Analysis ◽

Floating Wind Turbine

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

ASME 2019 2nd International Offshore Wind Technical Conference ◽

10.1115/iowtc2019-7577 ◽

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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Dynamic Response of Spar Wind Turbine Moored by Dynamic Catenaries Under Random Wind and Wave Loads

Volume 7A: Ocean Engineering ◽

10.1115/omae2019-95658 ◽

2019 ◽

Author(s):

Yilun Li ◽

Shuangxi Guo ◽

Yue Kong ◽

Weimin Chen ◽

Min Li

Keyword(s):

Dynamic Response ◽

Wind Turbine ◽

Integrated System ◽

Mooring Line ◽

Offshore Wind Turbine ◽

Response Analysis ◽

Flexible Beam ◽

Wave Loads ◽

Wave Load ◽

Floating Wind Turbine

Abstract As offshore wind turbine is developed toward larger water depth, the dynamics coming from structural and fluid inertia and damping effects of the mooring-line gets more obvious, that makes the response analysis of the large floating wind turbine under wind&wave load more challenging. In this study, the dynamic response of a spar floating wind turbine under random wind and wave loads is examined by the modified FEM simulations. Here an integrated system including flexible multi-bodies such as blades, tower, spar and mooring-lines is considered while the catenary dynamics is involved. The dynamic restoring performance of the catenary mooring-line is analyzed based on the vector equations of 3D curved flexible beam and its numerical simulations. Then the structural responses, e.g. the top tension, structural displacements and stress of the tower and the blade, undergoing random wind&wave loads, are examined. Morevoer, the influences of the catenary dynamics on its restoring performance and the hysteresis behavior are presented. Our numerical results show: the dynamics of mooring-line may significantly increase the top tension, and, particularly, the snap tension could be more than 3 times larger than the quasi-static one. Moreover, the structural response under random wind&wave load gets smaller mainly because of the hysteresis effect coming from the mooring-line dynamics. The floating body displacement at surge frequency is around 20% smaller, and the tower root stress at bending frequency is about 30% smaller than the quasi-static values respectively.

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Dynamic Response of an Offshore Wind Turbine System Using Coupled and Limited Coupled Methods

Volume 7: Ocean Space Utilization; Ocean Renewable Energy ◽

10.1115/omae2012-84146 ◽

2012 ◽

Cited By ~ 1

Author(s):

Fasuo Yan ◽

Cheng Peng ◽

Jun Zhang ◽

Dagang Wang

Keyword(s):

Dynamic Response ◽

Dynamic Analysis ◽

Wind Turbine ◽

Numerical Code ◽

Offshore Wind Turbine ◽

Response Analysis ◽

Time Step ◽

Coupled Method ◽

Floating Wind Turbine ◽

Wind Turbine System

Offshore turbines are gaining attention as means to capture the immense and relatively calm wind resources available over deep waters. A coupled dynamic analysis is required to evaluate the interactions between the wind turbine, floating hull and its mooring system. In this study, a coupled hydro-aero dynamic response analysis of a floating wind turbine system (NREL offshore-5MW baseline wind turbine) is carried out. A numerical code, known as COUPLE, has been extended to collaborate with FAST for the simulation of the dynamic interaction. Two methods were used in the analysis; one is coupled method and the other is limited coupled method. In the coupled method, the two codes are linked at each time step to solve the whole floating system. The limited coupled method assumes wind load is from a turbine installed on top of a fixed base, namely it doesn’t consider real-time configuration of floating carrier at each time step. Coupled technique is also mentioned to integrate the hydro-aero dynamic analysis in this paper. Six-degrees of freedom motion and mooring tensions are presented and compared. The numerical results derived in this study may provide crucial information for the design of a floating wind turbine in the future.

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Damage detection of TLP and Spar floating wind turbine using dynamic response of the structure

Ocean Engineering ◽

10.1016/j.oceaneng.2016.08.009 ◽

2016 ◽

Vol 125 ◽

pp. 191-202 ◽

Cited By ~ 14

Author(s):

Aysan Jamalkia ◽

Mir Mohammad Ettefagh ◽

Alireza Mojtahedi

Keyword(s):

Dynamic Response ◽

Damage Detection ◽

Wind Turbine ◽

Floating Wind Turbine

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Research on the Influence of Helical Strakes and Its Parameters on Dynamic Response of Platform of Floating Wind Turbine Based on Optimization Method of Orthogonal Design

Journal of Solar Energy Engineering ◽

10.1115/1.4037091 ◽

2017 ◽

Vol 139 (5) ◽

Cited By ~ 2

Author(s):

Qinwei Ding ◽

Chun Li ◽

Binxin Li ◽

Wenxing Hao ◽

Zhou Ye

Keyword(s):

Dynamic Response ◽

Wind Turbine ◽

Orthogonal Design ◽

Exciting Force ◽

Design Parameters ◽

Spar Platform ◽

Floating Wind Turbine ◽

Helical Strakes ◽

Pitch Ratio ◽

The Impact

The stability of platform is the most fundamental guarantee for the safe operation of floating wind turbine in complex marine environment. The helical strakes used on spar platform in the traditional oil industry are useful and effective. This paper is to investigative the validity of helical strakes when used for offshore wind energy harvesting. The National Renewable Energy Laboratory (NREL) 5 MW wind turbine based on OC3-Hywind spar-buoy platform with the attachment of helical strakes is modeled for the purpose to analysis the impact of helical strakes and its design parameters (number, height, and pitch ratio) on the dynamic response of the floating wind turbine spar platform. The dynamic response of spar platform under wind, wave, and current loads is calculated and analyzed based on the radiation and diffraction theory, the finite element method, and the orthogonal design method. The research result shows that the helical strakes can effectively suppress the dynamic response of the platform but enlarge the wave exciting force, and helical strakes cannot change peak frequency of response amplitude operator (RAO) and wave exciting force of spar in frequency-domain. The best parameter combination is two pieces of helical strakes with height of 15%D and the pitch ratio of 5. Height and pitch ratio of the helical strakes have significant influence on pitch response, while the number and interaction of height and pitch ratio have slight effect.

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