This paper briefly describes the implementation of a coupled near and far wake model for wind turbine rotor induction in the aeroelastic code HAWC2 and its application for flutter analysis of the NREL 5 MW wind turbine. The model consists of a far wake part based on Blade Element Momentum (BEM) theory, which is coupled with Beddoes’ near wake model for trailed vorticity. The first part of this ...

This paper is concerned with the protection of wind energy systems against the direct effects of lightning. As wind power generation undergoes rapid growth, lightning damages involving wind turbines have come to be regarded as a serious problem. Nevertheless, very few studies exist yet in Portugal regarding lightning protection of wind energy systems using numerical codes. A new case study is p...

A control strategy is realized which solve the problem of output power regulation of variable speed wind energy conversion systems by combining a linear control for blade pitch angle with a nonlinear H∞ torque control which mitigate the effects of external disturbances that occur at the input and output of the system. The controller exhibits better power and speed regulation when compared to cl...

Horizontal axis wind turbines suffer from aerodynamic inefficiencies in the blade root region (near the hub) due to several non-aerodynamic constraints. Aerodynamic interactions between turbines in a wind farm also lead to significant loss of wind farm efficiency. A new dual-rotor wind turbine (DRWT) concept is proposed that aims at mitigating these two losses. A DRWT is designed that uses an e...

The stratification of the atmospheric boundary layer (ABL) is classified in terms of the M-O length and subsequently used to determine the relationship between ABL stability and the fatigue loads of a wind turbine located inside an offshore wind farm. Recorded equivalent fatigue loads, representing blade-bending and tower bottom bending, are combined with the operational statistics from the ins...

In the next decennia, upscaling even towards 10 MW wind turbines may be necessary to lower the costs of offshore wind energy. This requires considerable reductions of turbine loads. Variable speed turbines with active pitch control are most favorable and prevailing nowadays. Currently, the turbine blades are turned collectively to limit the excess of wind power and to regulate the rotor speed a...

Li, Yuwei. "Coupled computational fluid dynamics/multibody dynamics method with application to wind turbine simulations." PhD ii To my family iii ACKNOWLEDGMENTS I would like to express my greatest appreciation to my advisor, Associate Professor Pablo M. Carrica, who has been continuously supporting me throughout my Ph.D. research with his knowledge, experience, enthusiasm and patience. I am gr...

In this study, a field testing has been carried out to assess the power characteristics of some small scale wind turbines fabricated by one native technician from Tanzania. Two Horizontal Axis Wind Turbines (HAWTs), one with five and other with sixteen blades were installed at a height of 2.4m above the ground. The rotation speed of the rotor blade and wind speed approaching the turbines were m...

Turbine blades of a gas turbine are responsible for extracting energy from the high temperature, high pressure gases. These blades are operated at elevated temperatures in aggressive environments and are subjected to large centrifugal forces. As many as 42 percent of the failures in gas turbine engines were only due to blading problems and the failures in these turbine blades can have dramatic ...

An experimental study was conducted to investigate the dynamic wind loads acting on a wind turbine model sited in atmospheric boundary layer winds. The experimental studies are conducted in a large-scale Aerodynamic/Atmospheric Boundary Layer (AABL) Wind Tunnel available at Iowa State University. A three-blade Horizontal Axial Wind Turbine (HAWT) model was placed in atmospheric boundary layer w...