Preliminary Analysis About Coupled Response of Offshore Floating Wind Turbine System in Time Domain

2015 ◽  
Author(s):  
Geliang Liu ◽  
Zhiqiang Hu ◽  
Fei Duan
Keyword(s):  
Wind Turbine ◽  
Time Domain ◽  
Preliminary Analysis ◽  
Oil And Gas ◽  
Wave Loads ◽  
Floating Wind Turbine ◽  
Wind Turbine System ◽  
Offshore Oil And Gas ◽  
Offshore Floating Wind Turbine ◽  
Offshore Oil

This paper presents a preliminary analysis of Offshore Floating Wind Turbine system subjected to coupled wind and wave loads in time domain. Floating Wind Turbine system in deep water has the great potential in exploiting renewable wind energy in the near future due to the energy and environmental issues. Distinct structural arrangements determine the complexity of motion behaviors and loading characteristics of OFWTs. The aerodynamic loads play a dominant part in the loading pattern, which is distinguished from traditional floating offshore oil and gas structures. To simulate the response induced by wind and wave, a calculation scheme is proposed containing the coupling between aerodynamics and hydrodynamics. Accordingly, a set of time-domain numerical codes is developed and presented. With the integrated aero and hydro dynamic analysis codes, simulations are conducted to obtain performance of Hywind system. Cases for decay, white noise, wind only and the coexistence of wind and wave are investigated. The results are compared to the test statistics collected from a model test, which was carried out in Deepwater Offshore Basin in Shanghai Jiao Tong University.

Coupled Aerodynamic and Hydroelastic Analysis of an Offshore Floating Wind Turbine System Under Wind and Wave Loads

2010 ◽  
Author(s):  
Kazuhiro Iijima ◽  
Junghyun Kim ◽  
Masahiko Fujikubo
Keyword(s):  
Wind Turbine ◽  
Time Domain ◽  
Response Analysis ◽  
Wave Loads ◽  
Structural System ◽  
Floating Structure ◽  
Floating Wind Turbine ◽  
Wind Turbine System ◽  
Offshore Floating Wind Turbine ◽  
The Impact

A numerical procedure for the fully coupled aerodynamic and hydroelastic time-domain analysis of an offshore floating wind turbine system including rotor blade dynamics, dynamic motions and flexible deflections of the structural system is illustrated. For the aerodynamic analysis of wind turbine system, a design code FAST developed by National Renewable Energy Laboratory (NREL) is employed. It is combined with a time-domain hydroelasticity response analysis code ‘Shell-Stress Oriented Dynamic Analysis Code (SSODAC)’ which has been developed by one of the authors. Then, the dynamic coupling between the rotating blades and the structural system under wind and wave loads is taken into account. By using this method, a series of analysis for the hydroelastic response of an offshore large floating structure with two rotors under combined wave and wind loads is performed. The results are compared with those under the waves and those under the winds, respectively, to investigate the coupled effects in terms of stress as well as motions. The coupling effects between the rotor-blades and the motions are observed in some cases. The impact on the structural design of the floating structure, tower and blade is addressed.

Revision of DNV GL Design Standard for Floating Wind Turbine Structures

2017 ◽  
Author(s):  
Anne Lene Haukanes Hopstad ◽  
Knut O. Ronold ◽  
Kimon Argyriadis
Keyword(s):  
Wind Turbine ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Gas Industry ◽  
Floating Structures ◽  
Current Trends ◽  
Floating Wind Turbine ◽  
Standard Design ◽  
Offshore Oil And Gas ◽  
Offshore Oil

The first edition of the DNV Offshore Standard “Design of Floating Wind Turbine Structures”, DNV-OS-J103, was published in June 2013. The standard represented a condensation of all relevant requirements for floaters in existing DNV standards for the offshore oil and gas industry which were considered relevant also for offshore floating structures for support of wind turbines, supplemented by necessary adaptation to the wind turbine application. As part of the harmonization of the DNV GL codes for the wind turbine industry after the merger between Det Norske Veritas (DNV) and Germanischer Lloyd (GL) in the autumn of 2013, DNV GL currently plans to publish a revision of DNV-OS-J103 in 2017, to become identified as DNVGL-ST-0119. The new revision is intended to reflect the experience gained since 2013 as well as the current trends within the industry.

Calibration of a Time-Domain Hydrodynamic Model for A 12 MW Semi-Submersible Floating Wind Turbine

2021 ◽  
Author(s):  
Carlos Eduardo Silva de Souza ◽  
Nuno Fonseca ◽  
Petter Andreas Berthelsen ◽  
Maxime Thys
Keyword(s):  
Numerical Model ◽  
Wind Turbine ◽  
Time Domain ◽  
Quadratic Model ◽  
Wave Loads ◽  
Frequency Wave ◽  
Load Models ◽  
Wave Drift ◽  
Floating Wind Turbine ◽  
Decay Tests

Abstract Design optimization of mooring systems is an important step towards the reduction of costs for the floating wind turbine (FWT) industry. Accurate prediction of slowly-varying horizontal motions is needed, but there are still questions regarding the most adequate models for low-frequency wave excitation, and damping, for typical FWT concepts. To fill this gap, it is fundamental to compare existing load models against model tests results. This paper describes a calibration procedure for a three-columns semi-submersible FWT, based on adjustment of a time-domain numerical model to experimental results in decay tests, and tests in waves. First, the numerical model and underlying assumptions are introduced. The model is then validated against experimental data, such that the adequate load models are chosen and adjusted. In this step, Newman’s approximation is adopted for the second-order wave loads, using wave drift coefficients obtained from the experiments. Calm-water viscous damping is represented as a linear and quadratic model, and adjusted based on decay tests. Additional damping from waves is then adjusted for each sea state, consisting of a combination of a wave drift damping component, and one component with viscous nature. Finally, a parameterization procedure is proposed for generalizing the results to sea states not considered in the tests.

scholarly journals Integrated Optimization of Floating Wind Turbine Systems

2014 ◽  
Author(s):  
Frank Sandner ◽  
David Schlipf ◽  
Denis Matha ◽  
Po Wen Cheng
Keyword(s):  
Wind Turbine ◽  
Degrees Of Freedom ◽  
Dynamic Models ◽  
Controller Design ◽  
Coupled Model ◽  
Optimal Solution ◽  
Wave Loads ◽  
Nonlinear Simulation ◽  
Floating Wind Turbine ◽  
Wind Turbine System

The purpose of this paper is to show an exemplary methodology for the integrated conceptioning of a floating wind turbine system with focus on the spar-type hull and the wind turbine blade-pitch-to-feather controller. It is a special interest to use a standard controller, which is easily implementable, even at early design stages. The optimization of the system is done with adapted static and dynamic models through a stepwise narrowing of the design space according to the requirements of floating wind turbines. After selecting three spar-type hull geometries with variable draft a simplified nonlinear simulation model with four degrees of freedom is set up and then linearized including the aerodynamics with the blade pitch controller in the closed-loop. The linear system allows conventional procedures for SISO controller design giving a theoretically suitable range of controller gains. Subsequently, the nonlinear model is used to find the optimal controller gains for each platform. Finally, a nonlinear coupled model with nine degrees of freedom gives the optimal solution under realistic wind and wave loads.

Revision of DNV Design Standard for Offshore Wind Turbine Structures

2007 ◽  
Author(s):  
Jakob Wedel-Heinen ◽  
Knut O. Ronold ◽  
Peter Hauge Madsen
Keyword(s):  
Wind Turbine ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Wave Loads ◽  
Gas Industry ◽  
Standard Design ◽  
Practical Guidelines ◽  
Offshore Oil And Gas

The first DNV-OS-J101 standard “Design of Offshore Wind Turbine Structures” [1] was issued in June 2004. The standard represented a condensation of all relevant requirements in DNV standards for the offshore oil and gas industry which were considered relevant also for offshore wind turbine structures, supplemented by necessary adaptation to the wind turbine application. Det Norske Veritas (DNV) plans to issue the next revision of DNV-OS-J101 [2] in 2007. The DNV revised standard now implements the requirements of the coming IEC 61400-3 standard [11], which was presented as a committee draft in 2006. Numerous practical guidelines have been included to help designers of offshore wind turbine structures to develop cost optimal designs. The present paper summarises the proposed revisions of DNV-OS-J101 [2]. The most important revisions cover new formulations for design load cases, modified partial safety factors, exclusion of transformer platforms, more information on wave loads in shallow water and a revised chapter for design of concrete structures.

Comparison of Time and Frequency Domain Simulations of an Offshore Floating Wind Turbine

2011 ◽  
Author(s):  
Maxime Philippe ◽  
Aure´lien Babarit ◽  
Pierre Ferrant
Keyword(s):  
Wind Turbine ◽  
Frequency Domain ◽  
Time Domain ◽  
Degrees Of Freedom ◽  
Domain Model ◽  
Floating Platform ◽  
Floating Wind Turbine ◽  
Non Linear ◽  
Offshore Floating Wind Turbine ◽  
The Time Domain

Time domain simulations of an offshore floating wind turbine have been performed. Hydrodynamic impulse responses of the floating platform are calculated with linear hydrodynamic simulation tool ACHIL3D. A user defined module for the wind turbine design code FAST has been developed to calculate hydrodynamic and mooring loads on the structure. Resolution of the movements of the system is done with FAST. Simulation results in time domain are compared with frequency domain results. In the frequency domain model, the whole system is linearized. In the time domain model, the wind turbine model is not linearized. A good agreement between time and frequency domain calculations is observed, even for the pitch motion. Furthermore we observe a non linearity in the response of sway, roll and yaw degrees of freedom around 0.3 rad.s-1. The effect of viscous damping on the movements of the floating wind turbine system has been studied with the time domain model, and a non linear hydrostatic and Froude-Krylov load model has been developed. Effects of these non linear terms are shown.

scholarly journals VERTICAL CAPACITY OF BUCKET FOUNDATIONS IN UNDRAINED SOIL

2014 ◽  
Vol 20 (3) ◽  
pp. 360-371 ◽  
Author(s):  
Amin Barari ◽  
Lars Bo Ibsen
Keyword(s):  
Wind Turbine ◽  
Oil And Gas ◽  
Field Tests ◽  
Oil And Gas Industry ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Vertical Load ◽  
Gas Industry ◽  
Offshore Oil And Gas ◽  
Offshore Oil

Offshore wind turbine structures are traditionally founded on gravity concrete foundations or mono-piles. Bucket foundations were developed for the offshore oil and gas industry and are now being used in wind turbine construction. The loading in this application is characterized by a vertical load due to the slender construction combined with horizontal forces inducing a large overturning moment. Field tests on bucket foundations were performed to gain insight into the vertical load response of bucket foundations in clay soils. The field tests were accompanied by finite element numerical simulations in order to provide a better understanding of the parameters influencing bucket foundation behaviour.

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