Analysis on dynamic interaction between flexible bodies of large-sized wind turbine and its response to random wind loads

As the output power of wind turbine increasingly gets larger, the structural flexibility of elastic bodies, such as rotor blades and tower, gets more significant owing to larger structural size. In that case, the dynamic interaction between these flexible bodies become more profound and may significantly impact the dynamic response of the whole wind turbine. In this study, the integrated model of a 5-MW wind turbine is developed based on the finite element simulations so as to carry out dynamic response analysis under random wind load, in terms of both time history and frequency spectrum, considering the interactions between the flexible bodies. And, the load evolution along its transmitting route and mechanical energy distribution during the dynamic response are examined. And, the influence of the stiffness and motion of the supporting tower on the integrated system is discussed. The basic dynamic characteristics and responses of 3 models, i.e. the integrated wind turbine model, a simplified turbine model (blades, hub and nacelle are simplified as lumped masses) and a rigid supported blade, are examined, and their results are compared in both time and frequency domains. Based on our numerical simulations, the dynamic coupling mechanism are explained in terms of the load transmission and energy consumption. It is found that the dynamic interaction between flexible bodies is profound for wind turbine with large structural size, e.g. the load and displacement of the tower top gets around 15% larger mainly due to the elastic deformation and dynamic behaviors (called inertial-elastic effect here) of the flexible blade; On the other hand, the elastic deformation may additionally consume around 10% energy (called energy-consuming effect) coming from external wind load and consequently decreases the displacement of the tower. In other words, there is a competition between the energy-consuming effect and inertial-elastic effect of the flexible blade on the overall dynamic response of the wind turbine. And similarly, the displacement of the blade gets up to 20% larger because the elastic-dynamic behaviors of the tower principally provides a elastic and moving support which can significantly change the natural mode shape of the integrated wind turbine and decrease the natural frequency of the rotor blade.

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Effects of incoming surface wind conditions on the wake characteristics and dynamic wind loads acting on a wind turbine model

Physics of Fluids ◽

10.1063/1.4904375 ◽

2014 ◽

Vol 26 (12) ◽

pp. 125108 ◽

Cited By ~ 32

Author(s):

Wei Tian ◽

Ahmet Ozbay ◽

Hui Hu

Keyword(s):

Wind Turbine ◽

Surface Wind ◽

Wind Loads ◽

Turbine Model ◽

Wake Characteristics

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Numerical Simulation of Dynamics of a Spar Type Floating Wind Turbine and Comparison With Laboratory Measurements

Volume 6: Ocean Space Utilization; Ocean Renewable Energy ◽

10.1115/omae2016-54149 ◽

2016 ◽

Cited By ~ 1

Author(s):

Hyunseong Min ◽

Cheng Peng ◽

Fei Duan ◽

Zhiqiang Hu ◽

Jun Zhang

Keyword(s):

Numerical Simulation ◽

Wind Speed ◽

Numerical Simulations ◽

Wind Turbine ◽

Wind Turbines ◽

Deep Water ◽

Offshore Wind ◽

Wind Loads ◽

Floating Offshore Wind Turbines ◽

The Cost

Wind turbines are popular for harnessing wind energy. Floating offshore wind turbines (FOWT) installed in relatively deep water may have advantages over their on-land or shallow-water cousins because winds over deep water are usually steadier and stronger. As the size of wind turbines becomes larger and larger for reducing the cost per kilowatt, it could bring installation and operation risks in the deep water due to the lack of track records. Thus, together with laboratory tests, numerical simulations of dynamics of FOWT are desirable to reduce the probability of failure. In this study, COUPLE-FAST was initially employed for the numerical simulations of the OC3-HYWIND, a spar type platform equipped with the 5-MW baseline wind turbine proposed by National Renewable Energy Laboratory (NREL). The model tests were conducted at the Deepwater Offshore Basin in Shanghai Jiao Tong University (SJTU) with a 1:50 Froude scaling [1]. In comparison of the simulation using COUPLE-FAST with the corresponding measurements, it was found that the predicted motions were in general significantly smaller than the related measurements. The main reason is that the wind loads predicted by FAST were well below the related measurements. Large discrepancies are expected because the prototype and laboratory wind loads do not follow Froude number similarity although the wind speed was increased (or decreased) in the tests such that the mean surge wind force matched that predicted by FAST at the nominal wind speed (Froude similarity) in the cases of a land wind turbine [1]. Therefore, an alternative numerical simulation was made by directly inputting the measured wind loads to COUPLE instead of the ones predicted by FAST. The related simulated results are much improved and in satisfactory agreement with the measurements.

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Predicting Wind Loads on the Topside of a Self-Propelled Wind Turbine Installation Jack-Up Using CFD

10.1115/omae2021-63445 ◽

2021 ◽

Author(s):

Zana Sulaiman

Keyword(s):

Boundary Layer ◽

Wind Tunnel ◽

Wind Turbine ◽

Full Range ◽

Design Tool ◽

Wind Loads ◽

Computational Domain ◽

Wind Tunnel Tests ◽

Jack Up ◽

Turbine Installation

Abstract This paper presents the results of wind load computational fluid dynamics (CFD) calculations performed on the topside structures of a self-propelled wind turbine installation jack-up. The CFD calculations were performed for the jack-up topside structures with and without the deck load. An atmospheric boundary layer profile was applied for the model-scale calculations. The full range of heading angles was considered. The CFD results were validated through comparison with the wind tunnel tests which were carried out at the German-Dutch wind tunnels (DNW) in Marknesse, The Netherlands. Moreover, a comparison is presented between the applied boundary layer profiles throughout the CFD computational domain with those profiles measured in the wind tunnel. The CFD results were found to be in good agreement with the wind tunnel tests for the considered cases, verifying the feasibility of the CFD method as an important design tool for the prediction of wind loads during the design processes of these types of jack-ups.

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Wind Effects on Sloshing of a Floating Roof in a Cylindrical Liquid Storage Tank

Volume 4: Fluid-Structure Interaction ◽

10.1115/pvp2008-61688 ◽

2008 ◽

Cited By ~ 1

Author(s):

Tetsuya Matsui ◽

Yasushi Uematsu ◽

Koji Kondo ◽

Takuo Wakasa ◽

Takashi Nagaya

Keyword(s):

Storage Tank ◽

Wind Tunnel Test ◽

Dynamic Interaction ◽

Measured Data ◽

Wind Pressure ◽

Wind Loads ◽

Linear Potential ◽

Liquid Storage ◽

Liquid Storage Tank ◽

Linear Potential Theory

Sloshing of a floating roof in an open-topped cylindrical liquid storage tank under wind loads is investigated analytically. Wind tunnel test in a turbulent boundary layer is carried out to measure the wind pressure distributing over the roof surface. The measured data for the wind pressure is then utilized to predict the wind-induced dynamic response of the floating roof, which is idealized herein as an isotropic elastic plate of uniform stiffness and mass. The dynamic interaction between the liquid and the floating roof is taken into account exactly within the framework of linear potential theory. Numerical results are presented which illustrate the significant effect of wind loads on the sloshing response of the floating roof.

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Failure analysis of wind turbine blade under critical wind loads

Engineering Failure Analysis ◽

10.1016/j.engfailanal.2012.08.002 ◽

2013 ◽

Vol 27 ◽

pp. 99-118 ◽

Cited By ~ 74

Author(s):

Jui-Sheng Chou ◽

Chien-Kuo Chiu ◽

I-Kui Huang ◽

Kai-Ning Chi

Keyword(s):

Failure Analysis ◽

Wind Turbine ◽

Turbine Blade ◽

Wind Turbine Blade ◽

Wind Loads

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Dynamic Responses of a Jacket-Type Offshore Wind Turbine Using Decoupled and Coupled Models

Volume 9B: Ocean Renewable Energy ◽

10.1115/omae2014-24246 ◽

2014 ◽

Cited By ~ 1

Author(s):

Muk Chen Ong ◽

Erin E. Bachynski ◽

Ole D. Økland ◽

Elizabeth Passano

Keyword(s):

Wind Turbine ◽

Coupled Model ◽

Dynamic Responses ◽

Time Dependent ◽

Offshore Wind ◽

Wind Loads ◽

Offshore Wind Turbine ◽

Coupled Models ◽

Thrust And Torque ◽

Rotor Model

This paper presents numerical studies of the dynamic responses of a jacket-type offshore wind turbine using both decoupled and coupled models. In the decoupled (hydroelastic) model, the wind load is included through time-dependent forces and moments at a single node on the top of the tower. The coupled model is a hydro-servo-aero-elastic representation of the system. The investigated structure is the OC4 (Offshore Code Comparison Collaboration Continuation) jacket foundation supporting the NREL 5-MW wind turbine in a water depth of 50m. Different operational wind and wave loadings at an offshore site with relatively high soil stiffness are investigated. The objective of this study is to evaluate the applicability of the computationally efficient linear decoupled model by comparing with the results obtained from the nonlinear coupled model. Good agreement was obtained in the eigen-frequency analysis, decay tests, and wave-only simulations. In order to obtain good results in the combined wind and wave simulations, two different strategies were applied in the decoupled model, which are 1) Wind loads obtained from the coupled model were applied directly as time-dependent point loads in the decoupled model; and 2) The thrust and torque from an isolated rotor model were used as wind loads on the decoupled model together with a linear aerodynamic damper. It was found that, by applying the thrust force from an isolated rotor model in combination with linear damping, reasonable agreement could be obtained between the decoupled and coupled models in combined wind and wave simulations.

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A Study about Security of Wind Turbine Foundation in Different Width and Height Ratios

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1079-1080.566 ◽

2014 ◽

Vol 1079-1080 ◽

pp. 566-573

Author(s):

Shi Jie Xu ◽

You Hua Fan ◽

Zhen Kun Wang

Keyword(s):

Wind Turbine ◽

Wind Turbines ◽

Wind Farm ◽

The Other ◽

Wind Loads ◽

Key Factors ◽

Height Ratio ◽

Geometry Feature ◽

Different Shapes ◽

The Relationship

Width and height ratio is a characteristic geometry feature of wind turbine foundations. This study establishes the relationship between security of wind turbine foundations and their width and height ratios. There are a number of works on checking wind turbines, however, limited works about how the width and height ratio influences the structure were conducted. This paper provides fifteen models of three different shapes, five circular foundations, five hexagon foundations and five triangle foundations. Data from a wind farm in Guizhou, China, is used to calculate the main wind loads acted on wind turbine structures. Then key factors concerning with security of foundations were obtained. And they were put together so that it is easy for us to find their relationships. The results show foundations have different performance at different ratios. It’s change laws were so clear, security of foundations is improved by the increasing of width and height ratio. On the other hand, hexagon and triangle foundations were certificated suitable for general projects.

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