Wind/Wave Misalignment in the Loads Analysis of a Floating Offshore Wind Turbine: Preprint

Wind/Wave Misalignment in the Loads Analysis of a Floating Offshore Wind Turbine: Preprint
Author:
Publisher:
Total Pages: 0
Release: 2014
Genre:
ISBN:

Wind resources far from the shore and in deeper seas have encouraged the offshore wind industry to look into floating platforms. The International Electrotechnical Commission (IEC) is developing a new technical specification for the design of floating offshore wind turbines that extends existing design standards for land-based and fixed-bottom offshore wind turbines. The work summarized in this paper supports the development of best practices and simulation requirements in the loads analysis of floating offshore wind turbines by examining the impact of wind/wave misalignment on the system loads under normal operation. Simulations of the OC3-Hywind floating offshore wind turbine system under a wide range of wind speeds, significant wave heights, peak-spectral periods and wind/wave misalignments have been carried out with the aero-servo-hydro-elastic tool FAST [4]. The extreme and fatigue loads have been calculated for all the simulations. The extreme and fatigue loading as a function of wind/wave misalignment have been represented as load roses and a directional binning sensitivity study has been carried out. This study focused on identifying the number and type of wind/wave misalignment simulations needed to accurately capture the extreme and fatigue loads of the system in all possible metocean conditions considered, and for a down-selected set identified as the generic US East Coast site. For this axisymmetric platform, perpendicular wind and waves play an important role in the support structure and including these cases in the design loads analysis canimprove the estimation of extreme and fatigue loads. However, most structural locations see their highest extreme and fatigue loads with aligned wind and waves. These results are specific to the spar type platform, but it is expected that the results presented here will be similar to other floating platforms.

Modeling of Extreme Waves in Technology and Nature, Two Volume Set

Modeling of Extreme Waves in Technology and Nature, Two Volume Set
Author: Shamil U. Galiev
Publisher: CRC Press
Total Pages: 862
Release: 2022-05-30
Genre: Science
ISBN: 1351059386

Modeling of Extreme Waves in Technology and Nature is a two-volume set, comprising Evolution of Extreme Waves and Resonances (Volume I) and Extreme Waves and Shock-Excited Processes in Structures and Space Objects (Volume II). The theory of waves is generalized on cases of extreme waves. The formation and propagation of extreme waves of various physical and mechanical nature (surface, elastoplastic, fracture, thermal, evaporation) in liquid and solid media, and in structural elements contacting with bubbly and cryogenic liquids are considered analytically and numerically. The occurrence of tsunamis, giant ocean waves, turbulence, and different particle-waves is described as resonant natural phenomena. Nonstationary and periodic waves are considered using models of continuum. The change in the state of matter is taken into account using wide-range determining equations. The desire for the simplest and at the same time general description of extreme wave phenomena that takes the reader to the latest achievements of science is the main thing that characterizes this book and is revolutionary for wave theory. A description of a huge number of observations, experimental data, and calculations is also given.

Offshore Wind Energy

Offshore Wind Energy
Author: Finn Gunnar Nielsen
Publisher: Cambridge University Press
Total Pages: 395
Release: 2024-02-29
Genre: Science
ISBN: 1009341448

Many countries have plans to expand wind energy to meet CO2 emissions targets. Lack of available land area and the need for good and stable wind conditions have stimulated the development of offshore wind turbines, which allows for the development of larger turbines. The offshore environment, however, involves new challenges related to the design, installation, operation and maintenance of the turbines. Based on a graduate-level course taught by the author, this book focuses on the opportunities and challenges related to offshore wind turbines. It introduces the offshore environment, including wind and wave dynamics, before discussing the aerodynamics of wind turbines, hydrodynamic loading, marine operations, and wind farm layout. Featuring examples that demonstrate practical application of the topics covered and exercises to consolidate student understanding, this is an indispensable reference text for advanced students and researchers of environmental science and engineering and for industry professionals working in the wind energy sector.

MARE-WINT

MARE-WINT
Author: Wiesław Ostachowicz
Publisher: Springer
Total Pages: 432
Release: 2016-08-30
Genre: Technology & Engineering
ISBN: 3319390953

This book provides a holistic, interdisciplinary overview of offshore wind energy, and is a must-read for advanced researchers. Topics, from the design and analysis of future turbines, to the decommissioning of wind farms, are covered. The scope of the work ranges from analytical, numerical and experimental advancements in structural and fluid mechanics, to novel developments in risk, safety & reliability engineering for offshore wind.The core objective of the current work is to make offshore wind energy more competitive, by improving the reliability, and operations and maintenance (O&M) strategies of wind turbines. The research was carried out under the auspices of the EU-funded project, MARE-WINT. The project provided a unique opportunity for a group of researchers to work closely together, undergo multidisciplinary doctoral training, and conduct research in the area of offshore wind energy generation. Contributions from expert, external authors are also included, and the complete work seeks to bridge the gap between research and a rapidly-evolving industry.

Evolution of Extreme Waves and Resonances

Evolution of Extreme Waves and Resonances
Author: Shamil U. Galiev
Publisher: CRC Press
Total Pages: 446
Release: 2020-06-10
Genre: Science
ISBN: 1000064018

The theory of waves is generalized on cases of strongly nonlinear waves, multivalued waves, and particle–waves. The appearance of these waves in various continuous media and physical fields is explained by resonances and nonlinearity effects. Extreme waves emerging in different artificial and natural systems from atom scale to the Universe are explored. Vast amounts of experimental data and comparisons of them with the results of the developed theory are presented. The book was written for graduate students as well as for researchers and engineers in the fields of geophysics, nonlinear wave studies, cosmology, physical oceanography, and ocean and coastal engineering. It is designed as a professional reference for those working in the wave analysis and modeling fields.

A Nonlinear Wave Load Model for Extreme and Fatigue Responses of Offshore Floating Wind Turbines

A Nonlinear Wave Load Model for Extreme and Fatigue Responses of Offshore Floating Wind Turbines
Author: Sungho Lee (Ph. D.)
Publisher:
Total Pages: 173
Release: 2012
Genre:
ISBN:

Ocean energy is one of the most important sources of alternative energy and offshore floating wind turbines are considered viable and economical means of harnessing ocean energy. The accurate prediction of nonlinear hydrodynamic wave loads and the resulting nonlinear motion and tether tension is of crucial importance in the design of floating wind turbines. A new theoretical framework is presented for analyzing hydrodynamic forces on floating bodies which is potentially applicable in a wide range of problems in ocean engineering. The total fluid force acting on a floating body is obtained by the time rate of change of the impulse of the velocity potential flow around the body. This new model called Fluid Impulse Theory is used to address the nonlinear hydrodynamic wave loads and the resulting nonlinear responses of floating wind turbine for various wave conditions in a highly efficient and robust manner in time domain. A three-dimensional time domain hydrodynamic wave-body interaction computational solver is developed in the frame work of a boundary element method based on the transient free-surface Green-function. By applying a numerical treatment that takes the free-surface boundary conditions linearized at the incident wave surface and takes the body boundary condition satisfied on the instantaneous underwater surface of the moving body, it simulates a potential flow in conjunction with the Fluid Impulse Theory for nonlinear wave-body interaction problems of large-amplitude waves and motions in time domain. Several results are presented from the application of the Fluid Impulse Theory to the extreme and fatigue wave load model: the time domain analysis of nonlinear dynamic response of floating wind turbine for extreme wave events and the time domain analysis of nonlinear wave load for an irregular sea state followed by a power spectral density analysis.

Wave Loads on Offshore Wind Turbines

Wave Loads on Offshore Wind Turbines
Author:
Publisher:
Total Pages: 65
Release: 2015
Genre:
ISBN:

Ocean energy is one of the most important sources of alternative energy and offshore floating wind turbines are considered viable and economical means of harnessing ocean energy. The accurate prediction of nonlinear hydrodynamic wave loads and the resulting nonlinear motion and tether tension is of crucial importance in the design of floating wind turbines. A new theoretical framework is presented for analyzing hydrodynamic forces on floating bodies which is potentially applicable in a wide range of problems in ocean engineering. The total fluid force acting on a floating body is obtained by the time rate of change of the impulse of the velocity potential flow around the body. This new model called Fluid Impulse Theory is used to address the nonlinear hydrodynamic wave loads and the resulting nonlinear responses of floating wind turbine for various wave conditions in a highly efficient and robust manner in time domain. A three-dimensional time domain hydrodynamic wave-body interaction computational solver is developed in the frame work of a boundary element method based on the transient free-surface Green-function. By applying a numerical treatment that takes the free-surface boundary conditions linearized at the incident wave surface and takes the body boundary condition satisfied on the instantaneous underwater surface of the moving body, it simulates a potential flow in conjunction with the Fluid Impulse Theory for nonlinear wave-body interaction problems of large amplitude waves and motions in time domain. Several results are presented from the application of the Fluid Impulse Theory to the extreme and fatigue wave load model: the time domain analysis of nonlinear dynamic response of floating wind turbine for extreme wave events and the time domain analysis of nonlinear wave load for an irregular sea state followed by a power spectral density analysis.