An Offshore Wind Energy Design Challenge: The Influence of Wind and Wave Load Combinations on the Extreme Response of Wind Turbines

University Of Texas At Austin, Austin TX

Investigators

Abstract

The main objective of this research project is to develop a probabilistic framework that will include the following features: (a) time-domain simulation of the random field describing the inflow turbulence structure over the swept area of the blades; (b) correlated wave kinematics and derived hydrodynamic loads (consistent with the wind field in (a)); (c) aerodynamic response of the wind turbines (utility-scale 2 to 5 MW turbines will be modeled); (d) stochastic descriptions of rotor/blade loads and support structure (tower) loads; and (e) statistical extrapolation of limited loads data to predict long-term design loads associated with the target service life (return periods on the order of 20 years). Very little published research relates to site-specific reliability-based design of offshore wind turbines, and the only (international) design code available prescribes an overly conservative envelope of design load cases for checking. This project will seek to answer some open questions in this area. Broader Impact: At the heart of this research effort is the education of graduate and undergraduate students who will develop skills in statistical modeling, wind and wave field simulation, aeroelastic and structural analysis, and safe design procedures for offshore wind turbines against ultimate (extreme) limit states. These skills, while not part of a typical curriculum, are urgently needed for a rapidly growing wind energy industry in this country and to limit our increased dependence on technical consulting assistance from engineers in Western Europe. Education and research activities will be focused in areas surrounding the modeling of the aerodynamic behavior of wind turbines and the complex hydrodynamic loading at near-shore sites. Sandia National Laboratories will provide internship opportunities for students; data sets and analysis software; technical oversight; and collaboration opportunities in research between their engineers and the PI and his students. With the help of the Equal Opportunity in Engineering (EOE) office at the PI's institution, minority students will be selected through the Texas Research EXperience (TREX) program as undergraduate research assistants and also offered summer internship opportunities at Sandia.