Analysis of Field Rotor Aerodynamic Measurements on Wind Turbines

INTRODUCTION

The Annexlyse project is funded by the Netherlands Agency for Energy and the Environment, NOVEM.
The aim of the project is to analyse aerodynamic field measurements on wind turbines, where the final goal is aerodynamic model improvement. The project started on May 1st 2002 and will end on November 30, 2003. Participants in the project are the Energy research Centre of the Netherlands, ECN and Delft University of Technology, DUT.
     The measurements that are analysed are stored in a database created in the research projects IEA Annex XIV and IEA Annex XVIII. In these IEA Annexes local aerodynamic properties (i.e. pressure distributions, lift, drag and moment coefficients, inflow angle, and inflow velocity) were taken from measurements at several radial positions on several turbines.
     The analysis performed in the Annexlyse project focuses on instationary and three-dimensional aerodynamic effects, among others in yaw. Furthermore a comparison is made between measured results and results calculated with design tools.
     A well known problem in the interpretation of field measurement results are the instationary and partly unknown inflow conditions. In order to overcome these problems it is attempted to extract measurements under best possible stationary conditions. 

RESULTS

Most of the Annexlyse results will be made public. To date the task 1 report  is completed. Within task 1 an overview is made of previouw analyses on the IEA Annex XVI/XVIII data. Furthermore a comparison is made between calculated and measured 3D sectional coefficients. The calculations have been performed with different 3D models, see also the paper for the EWEC 2003 conference.
Moreover a comparison is made (in draft) between results from ECN's aero-elastic code PHATAS and measured results from the IEA Annex XVIII time series.
More results will be published as soon as they become available.

CONTACTS

Gerard Schepers, Energy research Centre of the Netherlands, and
Ruud van Rooy, Delft University of Technology