Effect of Foundation Modelling Methodology on the Dynamic Response of Offshore Wind Turbine Support Structures

2011 ◽  
Author(s):  
Eric Van Buren
Keyword(s):  
Wind Turbine ◽  
Dynamic Properties ◽  
Dynamic Performance ◽  
Optimization Procedure ◽  
Operating Conditions ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Support Structures ◽  
Design Standards ◽  
Modelling Methodology

When preliminarily investigating offshore wind turbine tower concepts it is common to develop optimization software for determining the best possible structural layout. This type of optimization procedure requires a large number of iterations to determine the best possible design and can be quite time consuming, particularly if the dynamic performance of each structure is to be investigated using an aero-hydro-servo-elastic type solver. When performing this type of “dynamic optimization” it is convenient to simply assume fixed boundary conditions at the soil-structure interface and ignore the dynamic properties of the foundation. Using fixed conditions allows for each of the layouts to be compared quickly and makes the computer models simple to create and more efficient in computation than if the foundation is included. Alternatively, the foundations of offshore wind turbine support structures can be represented with several different methods of varying complexity and detail. The most widely used method is the use of a distributed spring model commonly known as the p-y method. This approach is the primary method in most offshore wind turbine design standards for determining the static and cyclic reaction of offshore piles. In this work, two offshore wind support structure layouts are modeled and analyzed in the wind turbine analysis program HAWC2. Dynamic time series analyses under operating conditions are carried out for each tower with fixed conditions and with foundation models based on the p-y method in order to determine the appropriateness of utilizing fixed foundation conditions for optimization procedures.

An Assessment of Structural Design Guidelines for Offshore Wind Turbines

2007 ◽  
Author(s):  
Rakesh K. Saigal ◽  
Dan Dolan ◽  
Armen Der Kiureghian ◽  
Tim Camp ◽  
Charles E. Smith
Keyword(s):  
Renewable Energy ◽  
Wind Turbine ◽  
Wind Farms ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Guidance Document ◽  
Support Structures ◽  
Design Standards ◽  
Offshore Wind Farms ◽  
Design Requirements

This paper addresses the need for U.S. standards to establish design requirements for offshore wind turbine support structures. There are wind power resources in U.S. waters that can be developed to generate substantial amounts of clean, renewable energy. While a number of offshore wind farms have been proposed for U.S. waters none have been built. The U.S. Minerals Management Service and the National Renewable Energy Laboratory have recently commissioned a study to compare and benchmark the International Electrotechnical Commission (IEC) design standards with the American Petroleum Institute (API) recommended practices. Offshore wind farms that are operating in Europe have been designed using standards developed specifically for offshore wind, such as those developed by Germanischer Lloyd (GL) and Det Norske Veritas (DNV). The IEC has recently drafted design requirements specifically for offshore wind farms that provides a comprehensive definition of load conditions and references other standards, where needed, to provide a complete guidance document. The intent of this paper is to examine the range of applicability of the various design standards and to assess how these standards apply to the design of U.S. offshore wind turbine (OWT) support structures.

Fatigue Life Analysis of Offshore Wind Turbine Support Structures in an Offshore Wind Farm

2018 ◽  
Author(s):  
Bryan Nelson ◽  
Yann Quéméner
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Farm ◽  
The Body ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Analysis Tool ◽  
Support Structures ◽  
Offshore Wind Farm ◽  
Actuator Disk

This study evaluated, by time-domain simulations, the fatigue lives of several jacket support structures for 4 MW wind turbines distributed throughout an offshore wind farm off Taiwan’s west coast. An in-house RANS-based wind farm analysis tool, WiFa3D, has been developed to determine the effects of the wind turbine wake behaviour on the flow fields through wind farm clusters. To reduce computational cost, WiFa3D employs actuator disk models to simulate the body forces imposed on the flow field by the target wind turbines, where the actuator disk is defined by the swept region of the rotor in space, and a body force distribution representing the aerodynamic characteristics of the rotor is assigned within this virtual disk. Simulations were performed for a range of environmental conditions, which were then combined with preliminary site survey metocean data to produce a long-term statistical environment. The short-term environmental loads on the wind turbine rotors were calculated by an unsteady blade element momentum (BEM) model of the target 4 MW wind turbines. The fatigue assessment of the jacket support structure was then conducted by applying the Rainflow Counting scheme on the hot spot stresses variations, as read-out from Finite Element results, and by employing appropriate SN curves. The fatigue lives of several wind turbine support structures taken at various locations in the wind farm showed significant variations with the preliminary design condition that assumed a single wind turbine without wake disturbance from other units.

State-of-the-art design processes for offshore wind turbine support structures

Stahlbau ◽  
2016 ◽  
Vol 85 (9) ◽  
pp. 583-590 ◽  
Author(s):  
Marc Seidel ◽  
Sven Voormeeren ◽  
Jan-Bart van der Steen
Keyword(s):  
Wind Turbine ◽  
State Of The Art ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Support Structures ◽  
Design Processes ◽  
Art Design
Sign in / Sign up

Export Citation Format

Share Document