Wave run-up on slender circular cylindrical foundations for offshore wind turbines in nonlinear random waves

2010 ◽  
Vol 57 (6) ◽  
pp. 567-574 ◽  
Author(s):  
Dag Myrhaug ◽  
Lars Erik Holmedal
Keyword(s):  
Wind Turbines ◽  
Offshore Wind ◽  
Random Waves ◽  
Offshore Wind Turbines ◽  
Run Up ◽  
Nonlinear Random Waves

Effects of Sand-Clay Mixtures on Scour Around Vertical Piles Due to Long-Crested and Short-Crested Nonlinear Random Waves

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Dag Myrhaug ◽  
Muk Chen Ong
Keyword(s):  
Coastal Ocean ◽  
Stochastic Method ◽  
Offshore Wind ◽  
Pile Foundations ◽  
Scour Depth ◽  
Regular Wave ◽  
Random Waves ◽  
Offshore Wind Turbines ◽  
Equilibrium Scour Depth ◽  
Nonlinear Random Waves

This note provides a practical stochastic method by which the effects of sand-clay mixtures on the maximum equilibrium scour depth around vertical piles exposed to long-crested (2D) and short-crested (3D) nonlinear random waves can be derived. This is made by using the regular wave formulas for scour depth for sand-clay mixtures by Dey et al. (2011, Scour at Vertical Piles in Sand-Clay Mixtures Under Waves,” J. Waterway, Port, Coastal, Ocean Eng., 137(6), pp. 324–331) and the stochastic method presented by Myrhaug and Ong (2013, “Scour Around Vertical Pile Foundations for Offshore Wind Turbines Due to Long-Crested and Short-Crested Nonlinear Random Waves,” ASME J. Offshore Mech. Arctic Eng., 135(1), p. 011103). Thus the present results are supplementary to those presented in the latter reference. An example calculation is provided.

Wave run-up on cylindrical and cone shaped foundations for offshore wind turbines

2007 ◽  
Vol 54 (1) ◽  
pp. 17-29 ◽  
Author(s):  
Leen De Vos ◽  
Peter Frigaard ◽  
Julien De Rouck
Keyword(s):  
Wind Turbines ◽  
Offshore Wind ◽  
Offshore Wind Turbines ◽  
Run Up

Scour Around Vertical Pile Foundations for Offshore Wind Turbines due to Long-Crested and Short-Crested Nonlinear Random Waves

2011 ◽  
Author(s):  
Dag Myrhaug ◽  
Muk Chen Ong
Keyword(s):  
Offshore Wind ◽  
Wave Crest ◽  
Random Wave ◽  
Scour Depth ◽  
Height Distribution ◽  
Random Waves ◽  
Offshore Wind Turbines ◽  
Nonlinear Random Waves ◽  
Wave Induced ◽  
2D And 3D

This paper provides a practical stochastic method by which the maximum scour depth around vertical piles exposed to long-crested (2D) and short-crested (3D) nonlinear random waves can be derived. The approach is based on assuming the waves to be a stationary narrow-band random process, adopting the Forristall (2000) wave crest height distribution representing both 2D and 3D nonlinear random waves, and using the regular wave formulas for scour depth by Sumer et al. (1992b). An example of calculation is provided. Tentative approaches to related random wave-induced scour cases are also suggested.

Pitch Angle Control of Floating Offshore Wind Turbines by H∞ Control

2014 ◽  
Vol 134 (8) ◽  
pp. 1096-1103 ◽  
Author(s):  
Sho Tsujimoto ◽  
Ségolène Dessort ◽  
Naoyuki Hara ◽  
Keiji Konishi
Keyword(s):  
Wind Turbines ◽  
Pitch Angle ◽  
Offshore Wind ◽  
Offshore Wind Turbines ◽  
Floating Offshore Wind Turbines

scholarly journals Maintenance Planning of Offshore Wind Turbine Using Condition Monitoring Information

2009 ◽  
Author(s):  
Jose´ G. Rangel-Rami´rez ◽  
John D. So̸rensen
Keyword(s):  
Condition Monitoring ◽  
Wind Turbines ◽  
Wind Farm ◽  
Offshore Structures ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Maintenance Planning ◽  
Offshore Wind Turbines ◽  
Inspection And Maintenance ◽  
Monitoring Information

Deterioration processes such as fatigue and corrosion are typically affecting offshore structures. To “control” this deterioration, inspection and maintenance activities are developed. Probabilistic methodologies represent an important tool to identify the suitable strategy to inspect and control the deterioration in structures such as offshore wind turbines (OWT). Besides these methods, the integration of condition monitoring information (CMI) can optimize the mitigation activities as an updating tool. In this paper, a framework for risk-based inspection and maintenance planning (RBI) is applied for OWT incorporating CMI, addressing this analysis to fatigue prone details in welded steel joints at jacket or tripod steel support structures for offshore wind turbines. The increase of turbulence in wind farms is taken into account by using a code-based turbulence model. Further, additional modes t integrate CMI in the RBI approach for optimal planning of inspection and maintenance. As part of the results, the life cycle reliabilities and inspection times are calculated, showing that earlier inspections are needed at in-wind farm sites. This is expected due to the wake turbulence increasing the wind load. With the integration of CMI by means Bayesian inference, a slightly change of first inspection times are coming up, influenced by the reduction of the uncertainty and harsher or milder external agents.

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