Extended Environmental Contour Methods for Long-Term Extreme Response Analysis of Offshore Wind Turbines1

Environmental contour method is an efficient method for predicting the long-term extreme response of offshore structures. The traditional environmental contour is obtained using the joint distribution of mean wind speed, significant wave height, and spectral peak period. To improve the accuracy of traditional environmental contour method, a modified method was proposed considering the non-monotonic aerodynamic behavior of offshore wind turbines. Still, the modified method assumes constant wind turbulence intensity. In this paper, we extend the existing environmental contour methods by considering the wind turbulence intensity as a stochastic variable. The 50-year extreme responses of a monopile-based offshore wind turbine are compared using the extended environmental contour methods and the full long-term method. It is found that both the environmental contour method and the modified environmental contour method, with the wind turbulence intensity included as an individual variable, give more accurate predictions compared with those without. Using the full long-term method as a benchmark, this extended approach could reduce the nonconservatism of the environmental contour method and conservatism of the modified environmental contour method. This approach is effective under wind-dominated or combined wind-wave loading conditions, but may not be as important for wave-dominated conditions.

[1]  M. Rosenblatt.  Remarks on a Multivariate Transformation , 1952 .

[2]  K. A. Semendyayev,et al.  Handbook of mathematics , 1985 .

[3]  Sverre Haver,et al.  ON THE JOINT DISTRIBUTION OF HEIGHTS AND PERIODS OF SEA WAVES , 1987 .

[4]  Knut Ronold,et al.  Ultimate Loading of Wind Turbines , 1999 .

[5]  Igor Rychlik,et al.  WAFO - A Matlab Toolbox For Analysis of Random Waves And Loads , 2000 .

[6]  Lance Manuel,et al.  Efficient models for wind turbine extreme loads using inverse reliability , 2004 .

[7]  B. Jonkman,et al.  TurbSim User's Guide , 2005 .

[8]  Gunner Chr. Larsen,et al.  Characterising Turbulence Intensity for Fatigue Load Analysis of Wind Turbines , 2005 .

[9]  Jason Jonkman,et al.  FAST User's Guide , 2005 .

[10]  Lance Manuel,et al.  Design Loads for Wind Turbines Using the Environmental Contour Method , 2006 .

[11]  J. Jonkman,et al.  Definition of a 5-MW Reference Wind Turbine for Offshore System Development , 2009 .

[12]  Jörg R. Seume,et al.  Investigation of Site-Specific Wind Field Parameters and Their Effect on Loads of Offshore Wind Turbines , 2012 .

[13]  Torgeir Moan,et al.  Joint Environmental Data at Five European Offshore Sites for Design of Combined Wind and Wave Energy Devices , 2013 .

[14]  Torgeir Moan,et al.  Extreme response analysis for a jacket-type offshore wind turbine using environmental contour method , 2014 .

[15]  Bent Natvig,et al.  Alternative environmental contours for structural reliability analysis , 2015 .

[16]  Torgeir Moan,et al.  Modified environmental contour method for predicting long-term extreme responses of bottom-fixed offshore wind turbines , 2016 .

[17]  Bernt J. Leira,et al.  Full long-term extreme response analysis of marine structures using inverse FORM , 2017 .

[18]  Erik Vanem,et al.  A comparison study on the estimation of extreme structural response from different environmental contour methods , 2017 .

[19]  Torgeir Moan,et al.  Modified environmental contour method to determine the long-term extreme responses of a semi-submersible wind turbine , 2017 .

[20]  Zhike Peng,et al.  The power performance of an offshore floating wind turbine in platform pitching motion , 2018, Energy.

[21]  Rebecca J. Barthelmie,et al.  A new seismic‐based monitoring approach for wind turbines , 2018, Wind Energy.

[22]  Zhengru Ren,et al.  Active tugger line force control for single blade installation , 2018, Wind Energy.

[23]  Zhengru Ren,et al.  Impact assessment of a wind turbine blade root during an offshore mating process , 2019, Engineering Structures.

[24]  T. Tezdogan,et al.  Investigation on long-term extreme response of an integrated offshore renewable energy device with a modified environmental contour method , 2019, Renewable Energy.

[25]  Ye Li,et al.  Effect of Wind Turbulence on Extreme Load Analysis of an Offshore Wind Turbine , 2019, Volume 1: Offshore Technology; Offshore Geotechnics.