Natural period design consideration for tension leg platform wind turbine

2014 ◽  
Author(s):  
Haifeng Wang ◽  
Youhua Fan
Keyword(s):  
Wind Turbine ◽  
Design Consideration ◽  
Tension Leg Platform ◽  
Natural Period

Small scale experimental study of the dynamic response of a tension leg platform wind turbine

2014 ◽  
Vol 6 (5) ◽  
pp. 053108 ◽  
Author(s):  
Anders Mandrup Hansen ◽  
Robert Laugesen ◽  
Henrik Bredmose ◽  
Robert Mikkelsen ◽  
Nikolaos Psichogios
Keyword(s):  
Experimental Study ◽  
Dynamic Response ◽  
Wind Turbine ◽  
Small Scale ◽  
Tension Leg Platform

Stochastic Analysis of Short-Term Structural Responses and Fatigue Damages of A Submerged Tension Leg Platform Wind Turbine in Wind and Waves

2021 ◽  
Vol 35 (4) ◽  
pp. 566-577
Author(s):  
Yan-qing Han ◽  
Cong-huan Le ◽  
Pu-yang Zhang ◽  
Li Dang ◽  
Qing-lai Fan
Keyword(s):  
Wind Turbine ◽  
Stochastic Analysis ◽  
Short Term ◽  
Tension Leg Platform ◽  
Structural Responses

scholarly journals Loads and Response of a Tension Leg Platform Wind Turbine with Non-Rotating Blades: An Experimental Study

2019 ◽  
Vol 7 (3) ◽  
pp. 56 ◽  
Author(s):  
Timothy Murfet ◽  
Nagi Abdussamie
Keyword(s):  
Wind Turbine ◽  
Degrees Of Freedom ◽  
Wind Loading ◽  
Dominant Factor ◽  
Tension Leg Platform ◽  
Rotating Blades ◽  
Motion Responses ◽  
Free Decay ◽  
Response Amplitude Operators ◽  
Decay Tests

This paper describes model testing of a Tension Leg Platform Wind Turbine (TLPWT) with non-rotating blades to better understand its motion and tendon responses when subjected to combined wind and unidirectional regular wave conditions. The TLPWT structure is closely based on the National Renewable Energy Laboratory (NREL) 5 MW concept. Multiple free decay tests were performed to evaluate the natural periods of the model in the key degrees of freedom, whilst Response Amplitude Operators (RAOs) were derived to show the motion and tendon characteristics. The natural periods in surge and pitch motions evaluated from the decay tests had a relatively close agreement to the theoretical values. Overall, the tested TLPWT model exhibited typical motion responses to that of a generalised TLP with significant surge offsets along with stiff heave and pitch motions. The maximum magnitudes for the RAOs of surge motion and all tendons occurred at the longest wave period of 1.23 s (~13.0 s at full-scale) tested in this study. From the attained results, there was evidence that static wind loading on the turbine structure had some impact on the motions and tendon response, particularly in the heave direction, with an average increase of 13.1% in motion amplitude for the tested wind conditions. The wind had a negligible effect on the surge motion and slightly decreased the tendon tensions in all tendons. The results also showed the set-down magnitudes amounting to approximately 2–5% of the offset. Furthermore, the waves are the dominant factor contributing to the set-down of the TLPWT, with a minimal contribution from the static wind loading. The results of this study could be used for calibrating numerical tools such as CFD codes.

scholarly journals Spoke Dimension on the Motion Performance of a Floating Wind Turbine with Tension-Leg Platform

2016 ◽  
Vol 2016 ◽  
pp. 1-16
Author(s):  
H. F. Wang ◽  
Y. H. Fan
Keyword(s):  
Wind Turbine ◽  
Good Choice ◽  
Offshore Wind ◽  
Experimental Result ◽  
Offshore Wind Turbine ◽  
Tension Leg Platform ◽  
Irregular Wave ◽  
Wind Turbine System ◽  
Floating Offshore Wind Turbines ◽  
Tower Structure

The tension-leg platform (TLP) supporting structure is a good choice for floating offshore wind turbines because TLP has superior motion dynamics. This study investigates the effects of TLP spoke dimensions on the motion of a floating offshore wind turbine system (FOWT). Spoke dimension and offshore floating TLP were subjected to irregular wave and wind excitation to evaluate the motion of the FOWT. This research has been divided into two parts: (1) Five models were designed based on different spoke dimensions, and aerohydroservo-elastic coupled analyses were conducted on the models using the finite element method. (2) Considering the coupled effects of the dynamic response of a top wind turbine, a supporting-tower structure, a mooring system, and two models on a reduced scale of 1 : 80 were constructed and experimentally tested under different conditions. Numerical and experimental results demonstrate that the spoke dimensions have a significant effect on the motion of FOWT and the experimental result that spoke dimension can reduce surge platform movement to improve turbine performance.

CFD Simulation of Semi-Submersible Floating Offshore Wind Turbine Under Pitch Decay Motion

2019 ◽  
Author(s):  
Yu Wang ◽  
Hamn-Ching Chen ◽  
Guilherme Vaz ◽  
Simon Burmester
Keyword(s):  
Wind Turbine ◽  
Cfd Simulation ◽  
Flow Characteristics ◽  
Hydrodynamic Pressure ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Natural Period ◽  
Hydrodynamic Damping ◽  
Computational Data ◽  
Computational Fluid Dynamics Cfd

Abstract The application of a computational fluid dynamics (CFD) code to simulate the response of a semi-submersible floating wind turbine under pitch decay motion was investigated in this study. Estimation of the natural period, the hydrodynamic damping and the flow characteristics were the main focus of this study. An extensive verification study of the simulation results was conducted to improve the confidence and reliability of the numerical simulation by the estimation of the numerical errors and uncertainties. The time series of pitch motion was plotted against model test data. In addition, the pitch period and hydrodynamic damping were calculated and compared to experimental data. Detailed flow characteristics as vorticity field and hydrodynamic pressure field on the floater surface were illustrated after post processing of the computational data. The results of the flow characteristics suggest that the heave damping plates were a major contributor to the hydrodynamic damping of this floater in pitch decay.

scholarly journals Study of Floating Wind Turbine with Modified Tension Leg Platform Placed in Regular Waves

Energies ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 703 ◽  
Author(s):  
Juhun Song ◽  
Hee-Chang Lim
Keyword(s):  
Wind Turbine ◽  
Real Data ◽  
Offshore Wind ◽  
Scale Model ◽  
Offshore Wind Turbine ◽  
Wave Loads ◽  
Tension Leg Platform ◽  
Mooring Lines ◽  
Floating Wind Turbine ◽  
Wave Conditions

In this study, the typical ocean environment was simulated with the aim to investigate the dynamic response under various environmental conditions of a Tension Leg Platform (TLP) type floating offshore wind turbine system. By applying Froude scaling, a scale model with a scale of 1:200 was designed and model experiments were carried out in a lab-scale wave flume that generated regular periodic waves by means of a piston-type wave generator while a wave absorber dissipated wave energy on the other side of the channel. The model was designed and manufactured based on the standard prototype of the National Renewable Energy Laboratory (NREL) 5 MW offshore wind turbine. In the first half of the study, the motion and structural responses for operational wave conditions of the North Sea near Scotland were considered to investigate the performance of a traditional TLP floating wind turbine compared with that of a newly designed TLP with added mooring lines. The new mooring lines were attached with the objective of increasing the horizontal stiffness of the system and thereby reducing the dominant motion of the TLP platform (i.e., the surge motion). The results of surge translational motions were obtained both in the frequency domain, using the response amplitude operator (RAO), and in the time domain, using the omega arithmetic method for the relative velocity. The results obtained show that our suggested concept improves the stability of the platform and reduces the overall motion of the system in all degrees-of-freedom. Moreover, the modified design was verified to enable operation in extreme wave conditions based on real data for a 100-year return period of the Northern Sea of California. The loads applied by the waves on the structure were also measured experimentally using modified Morison equation—the formula most frequently used to estimate wave-induced forces on offshore floating structures. The corresponding results obtained show that the wave loads applied on the new design TLP had less amplitude than the initial model and confirmed the significant contribution of the mooring lines in improving the performance of the system.

Effects of Hull Flexibility on the Structural Dynamics of a Tension Leg Platform Floating Wind Turbine

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Carlos Eduardo Silva de Souza ◽  
Erin E. Bachynski
Keyword(s):  
Wind Turbine ◽  
Fatigue Damage ◽  
Structural Response ◽  
Wave Excitation ◽  
Short Term ◽  
Tension Leg Platform ◽  
Flexible Beams ◽  
Fatigue Damage Accumulation ◽  
Vertical Deformations ◽  
Motion Amplitude

Abstract Dynamic analysis of floating wind turbines often considers the hull as a rigid body. This paper explores the consequences of modeling the pontoons of a tension leg platform (TLP) wind turbine as flexible beams. The analysis is based on numerical simulations of free decays, structural response to wave excitation, and short-term fatigue damage accumulation at tower base and tendons. In addition, the importance of hydroelastic effects due to the pontoons’ vertical deformations is evaluated. Pontoon flexibility changed the platform natural periods and motion amplitude significantly, and the adoption of flexible pontoons reduced the predicted fatigue damage in the tower base and tendons. On the other hand, hydroelasticity had negligible consequences for motion and load responses considered here.

Hydrodynamic design of a free-float capable tension leg platform for a 10 MW wind turbine

2020 ◽  
Vol 197 ◽  
pp. 106888 ◽  
Author(s):  
Emre Uzunoglu ◽  
C. Guedes Soares
Keyword(s):  
Wind Turbine ◽  
Tension Leg Platform
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