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Conference programme 

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Poster session

Lead Session Chair:
Stephan Barth, Managing Director, ForWind - Center for Wind Energy Research, Germany
John Obrecht Siemens, United States
Co-authors:
John Obrecht (1) F P Jennifer Frankland (1) Justin Creaby (1) Drew Gertz (2)
(1) Siemens Wind Power, Boulder, CO, United States (2) Siemens Wind Power, Ballerup, Denmark

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Poster
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Presenter's biography

Biographies are supplied directly by presenters at OFFSHORE 2015 and are published here unedited

Dr. Obrecht has been a Research & Development Engineer with Siemens Wind Power for the past 6 years, working in areas associated with the design and validation of wind turbine blades. Most recently, his work has been focused on rotor validation, utilizing the highly-instrumented Siemens test turbine located at the National Wind Technology Center in Boulder, CO.

Abstract

Nacelle-mounted lidar measurement of the axial induction of a wind turbine

Introduction

A forward-looking LIDAR unit was installed upon the nacelle of a Siemens wind turbine (SWT-2.3-108) at the National Wind Technology Center in Boulder, CO. The LIDAR unit was used to measure the velocity of the wind 40-200m upstream of the turbine’s rotor during operation, with the intention of not only measuring the axial induction of wind speed leading up to the turbine, but also to demonstrate measurement capabilities and competence with forward-looking LIDAR units.

Approach

The approach that was used was that incoming wind speeds would be measured every 20m from 40-200m upstream of the turbine. The axial induction effects from the operational turbine are expected to slow down with a distance scale on the order of the rotor size, and should follow a well-described functional form. Analysis of the induction effects can then demonstrate the measurement capabilities of the experiment.

Main body of abstract

A forward-looking LIDAR unit was installed upon the nacelle of a Siemens wind turbine (SWT-2.3-108) at the National Wind Technology Center in Boulder, CO. The LIDAR unit was used to measure the velocity of the wind 40-200m upstream of the turbine’s rotor during operation. Analysis of the LIDAR measurements clearly shows the induction of the wind in front of the rotor plane. The magnitude, length scale, and velocity dependence of the induction field agree well with theoretical models and CFD calculations, confirming our understanding of the influence of an operational wind turbine on the upstream flow field.

Conclusion

Analysis of the LIDAR measurements clearly shows the induction of the wind in front of the rotor plane. The magnitude, length scale, and velocity dependence of the induction field agree well with theoretical models and CFD calculations, confirming our understanding of the influence of an operational wind turbine on the upstream flow field.


Learning objectives
The objectives for this experiment were to demonstrate measurement capabilities and competence of forward-looking LIDAR units with an operational, industrial-scale wind turbine, and to also confirm the well-established effect of the rotor on the wind field.