Short and Long Term Extreme Reliability Analysis Applied to Floating Wind Turbine Design

2011 ◽  
Author(s):  
Timothe´e Perdrizet ◽  
Daniel Averbuch
Keyword(s):  
Wind Turbine ◽  
International Energy Agency ◽  
Energy Agency ◽  
Floating Wind Turbine ◽  
Extreme Response ◽  
Short And Long Term ◽  
Turbine Design ◽  
Wave Induced

This paper describes and exemplifies an efficient methodology to assess, jointly and in a single calculation, the short and long terms failure probabilities associated to the extreme response of a floating wind turbine, subjected to wind and wave induced loads. This method is applied to the realistic case study OC3-Hywind used in phase IV of the IEA (International Energy Agency) Annex XXIII Offshore Code Comparison Collaboration. The key point of the procedure, derived from the outcrossing approach, consists in computing the mean of the outcrossing rate of the floating wind turbine response in the failure domain over both the short term variables and the ergodic variables defining long term parameters.

scholarly journals Multipoint high-fidelity CFD-based aerodynamic shape optimization of a 10 MW wind turbine

2019 ◽  
Vol 4 (2) ◽  
pp. 163-192 ◽  
Author(s):  
Mads H. Aa. Madsen ◽  
Frederik Zahle ◽  
Niels N. Sørensen ◽  
Joaquim R. R. A. Martins
Keyword(s):  
Shape Optimization ◽  
Wind Turbine ◽  
International Energy Agency ◽  
Operating Conditions ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
High Fidelity ◽  
Energy Agency ◽  
Cross Sectional

Abstract. The wind energy industry relies heavily on computational fluid dynamics (CFD) to analyze new turbine designs. To utilize CFD earlier in the design process, where lower-fidelity methods such as blade element momentum (BEM) are more common, requires the development of new tools. Tools that utilize numerical optimization are particularly valuable because they reduce the reliance on design by trial and error. We present the first comprehensive 3-D CFD adjoint-based shape optimization of a modern 10 MW offshore wind turbine. The optimization problem is aligned with a case study from International Energy Agency (IEA) Wind Task 37, making it possible to compare our findings with the BEM results from this case study and therefore allowing us to determine the value of design optimization based on high-fidelity models. The comparison shows that the overall design trends suggested by the two models do agree, and that it is particularly valuable to consult the high-fidelity model in areas such as root and tip where BEM is inaccurate. In addition, we compare two different CFD solvers to quantify the effect of modeling compressibility and to estimate the accuracy of the chosen grid resolution and order of convergence of the solver. Meshes up to 14×106 cells are used in the optimization whereby flow details are resolved. The present work shows that it is now possible to successfully optimize modern wind turbines aerodynamically under normal operating conditions using Reynolds-averaged Navier–Stokes (RANS) models. The key benefit of a 3-D RANS approach is that it is possible to optimize the blade planform and cross-sectional shape simultaneously, thus tailoring the shape to the actual 3-D flow over the rotor. This work does not address evaluation of extreme loads used for structural sizing, where BEM-based methods have proven very accurate, and therefore will likely remain the method of choice.

Long Term Wind Turbine Performance Analysis Through SCADA Data: A Case Study

2021 ◽  
Author(s):  
Davide Astolfi ◽  
Gabriele Malgaroli ◽  
Filippo Spertino ◽  
Angela Amato ◽  
Andrea Lombardi ◽  
...  
Keyword(s):  
Performance Analysis ◽  
Wind Turbine ◽  
Turbine Performance

Comparison of Spar and Semisubmersible Floater Concepts of Offshore Wind Turbines Using Long-Term Analysis

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Hasan Bagbanci ◽  
D. Karmakar ◽  
C. Guedes Soares
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Transfer Functions ◽  
Probability Distributions ◽  
Offshore Wind ◽  
Short Term ◽  
Offshore Wind Turbines ◽  
Floating Wind Turbine ◽  
Offshore Floating Wind Turbine

The long-term probability distributions of a spar-type and a semisubmersible-type offshore floating wind turbine response are calculated for surge, heave, and pitch motions along with the side-to-side, fore–aft, and yaw tower base bending moments. The transfer functions for surge, heave, and pitch motions for both spar-type and semisubmersible-type floaters are obtained using the fast code and the results are also compared with the results obtained in an experimental study. The long-term predictions of the most probable maximum values of motion amplitudes are used for design purposes, so as to guarantee the safety of the floating wind turbines against overturning in high waves and wind speed. The long-term distribution is carried out using North Atlantic wave data and the short-term floating wind turbine responses are represented using Rayleigh distributions. The transfer functions are used in the procedure to calculate the variances of the short-term responses. The results obtained for both spar-type and semisubmersible-type offshore floating wind turbine are compared, and the study will be helpful in the assessments of the long-term availability and economic performance of the spar-type and semisubmersible-type offshore floating wind turbine.

scholarly journals Effects of bedplate flexibility on drivetrain dynamics: Case study of a 10 MW spar type floating wind turbine

2020 ◽  
Vol 161 ◽  
pp. 808-824
Author(s):  
Shuaishuai Wang ◽  
Amir R. Nejad ◽  
Erin E. Bachynski ◽  
Torgeir Moan
Keyword(s):  
Wind Turbine ◽  
Floating Wind Turbine

Towards a Methodology for Monitoring and Analyzing the Supply Chain Behavior

2011 ◽  
pp. 186-208
Author(s):  
Reinaldo Moraga ◽  
Luis Rabelo ◽  
Alfonso Sarmiento
Keyword(s):  
Neural Networks ◽  
Sensitivity Analysis ◽  
Supply Chain ◽  
System Dynamics ◽  
Eigenvalue Analysis ◽  
Background Information ◽  
Short And Long Term ◽  
And Performance

In this chapter, the authors present general steps towards a methodology that contributes to the advancement of prediction and mitigation of undesirable supply chain behavior within short- and long- term horizons by promoting a better understanding of the structure that determines the behavior modes. Through the integration of tools such as system dynamics, neural networks, eigenvalue analysis, and sensitivity analysis, this methodology (1) captures the dynamics of the supply chain, (2) detects changes and predicts the behavior based on these changes, and (3) defines needed modifications to mitigate the unwanted behaviors and performance. In the following sections, some background information is given from literature, the general steps of the proposed methodology are discussed, and finally a case study is briefly summarized.

Acoustic Techniques for Wind Turbine Blade Monitoring

2007 ◽  
Vol 347 ◽  
pp. 639-644 ◽  
Author(s):  
Kenneth Burnham ◽  
Gareth Pierce
Keyword(s):  
Wind Turbine ◽  
Structural Integrity ◽  
International Energy Agency ◽  
Rotor Blades ◽  
Wind Generation ◽  
Energy Agency ◽  
Wind Turbine System ◽  
Acoustic Techniques ◽  
The Uk ◽  
Electrical Generation

The total electrical generation capacity from wind sources in the International Energy Agency (IEA) Wind Member Countries has increased from 4 GW in 1995 to more than 51 GW in 2005 thus underlining the strategic importance of the resource. In the last year alone the UK increased its wind generation by 447 MW, an increase of 85% over that for the previous year. In 2004, wind generation formed just 0.5% of the national electric demand; this contribution is set to rise over the next few years with some predictions that wind energy will rise to 8% of the total UK demand by 2010. The rotor blades of a wind turbine system are a significant structural component of the overall system, and typically account for 30% of lifecycle costs, and contribute 34% to overall system downtime. Despite their importance, there is currently very little monitoring of the structural integrity of rotor components, and what does exist is limited. We perceive that especially with the current political and technological emphasis on offshore installations, there will be an increase in the perceived need for remote structural monitoring, and there is indeed currently great interest in this area from the wind turbine industry. This work focuses on the applications of acoustic techniques to assess the integrity of typical rotor blade structures. Preliminary results discuss the limiting aspects of acoustic based techniques based on the physics of acoustic wave propagation in typical structural components. Comparisons between acoustic emission approaches and conventional active ultrasound will be considered.

Impact of a Wind Turbine Blade Pitch Rate on a Floating Wind Turbine During an Emergency Shutdown Operation

2020 ◽  
Author(s):  
Pauline Louazel ◽  
Daewoong Son ◽  
Bingbin Yu
Keyword(s):  
Wind Turbine ◽  
Turbine Blades ◽  
Floating Platform ◽  
Floating Structure ◽  
Rapid Variation ◽  
Emergency Shutdown ◽  
Floating Wind Turbine ◽  
Time Period ◽  
Wave Induced ◽  
Loss Of Thrust

Abstract During the shutdown of a wind turbine, the turbine blades rotate from their typical operating angle to their typical idling angle (approximately 90 degrees) at a specific speed, called the blade pitch rate. This operation leads to rapid loss of thrust force on the turbine resulting in a corresponding heel response of the floating structure. This rapid variation of loads at the turbine also leads to large nacelle accelerations which are transferred to the bottom of the tower and consequently to the floating structure, making the turbine shutdowns, and specifically emergency shutdowns, of significance in the design and certification of the turbine, tower and floating structure. In case of an emergency shutdown (for instance due to a grid loss), the blades typically pitch from 0 degree to 90 degrees in approximately 20–35 seconds, whereas this time period can be more than 100 seconds in the case of a normal shutdown [6]. For fixed-bottom wind turbines, increasing the blade pitch rate leads to an increase of instantaneous loads at the nacelle and tower, leading to the emergency shutdown pitch rate being usually chosen to be as low as possible. In the case of a floating wind turbine, however, water/platform interaction effects such as wave induced damping on the floating platform, challenge this approach. Indeed, increasing the blade pitch rate can increase the effect of wave-induced damping on the floater and therefore reduce the loads on the overall structure. On the other hand, reducing the blade pitch rate during an emergency shutdown can reduce this damping effect and increase those loads, meaning that an optimal blade pitch rate for a fixed bottom turbine is not necessarily optimal for a floating wind turbine. This paper will examine the behavior of a floating offshore semi-submersible platform, the WindFloat, during turbine shutdown operations, with an emphasis on the blade pitch rate during an emergency shutdown.

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