Service Communautaire d'Information sur la Recherche et le Développement - CORDIS

Blade design for horizontal axis wind turbines across Europe

The project brings together the modelling research on blade design for horizontal axis wind turbines across Europe. Experiments and different theoretical models have been investigated to increase the understanding of the 3-dimensional and unsteady aerodynamics of stall controlled horizontal axis wind turbines (HAWT). Also, 'engineering models' are developed that are suitable for implementation in programs for aero-elastic calculations for dynamic stall and 3-dimensional effects.

Measurements on several rotating and non-rotating wind turbine blades were used to analyse 3-dimensional effects. From these experiments, aerodynamic section co-efficients as a function of angle of attack were determined. These data were used for comparison with expected 2-dimensional characteristics. Measurements on rotor blades carried out in a wind tunnel and field rotor measurements under conditions with low wind turbulence, provided information on 'quasi-steady' 3-dimensional flow. Risø field rotor measurements during turbulent conditions and during yawed operation provided unsteady data that were used for comparison with Navier-Stokes calculations and simulations with five different dynamic stall prediction models which were validated.

Improvements have been made in the capabilities of calculating the viscous flow around wind turbine blades. Separated 3-dimensional flow was, for some cases, well-predicted and certain aspects of dynamic stall were investigated. Still, Navier-Stokes solutions are shown to be highly sensitive to the choice of turbulence models. The 3-dimensional solutions were obtained with course grids and rather simplified boundary conditions. In order to increase the possibility of understanding of unsteady aerodynamics and 3-dimensional effects, both in general and for specific new designs, it is recommended that further work related to turbulence models for Navier-Stokes methods is done.

Reported by

The Aeronautical Research Institute of Sweden
Ranhammarsv. 12-14
16111 Bromma
Sweden
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