Comparison between experiments and Large-Eddy Simulations of tip spiral structure and geometry

Stefan Ivanell (1, 2) , Thomas Leweke (3) , Sasan Sarmast (1) , Hugo Umberto Quaranta (3) , Robert F Mikkelsen (4) , Jens Nørkær Sørensen (1, 4)

1 Uppsala University - Wind Energy Section
2 KTH Mechanics
3 IRPHE - Institut de Recherche sur les Phénomènes Hors Equilibre
4 Wind Energy Division [Roskilde]

Results from Large-Eddy Simulations using the actuator line technique have been validated against experimental results. The experimental rotor wake, which forms the basis for the comparison, was studied in a recirculating free-surface water channel, where a helical vortex was generated by a single-bladed rotor mounted on a shaft. An investigation of how the experimental blade geometry and aerofoil characteristics affect the results was performed. Based on this, an adjustment of the pitch setting was introduced, which is still well within the limits of the experimental uncertainty. Excellent agreement between the experimental and the numerical results was achieved concerning the circulation, wake expansion and pitch of the helical tip vortex. A disagreement was found regarding the root vortex position and the axial velocity along the centre line of the tip vortex. This work establishes a good base for further studies of more fundamental stability parameters of helical rotor wakes.

Mots clés: STABILITY; VORTICES; WIND TURBINE

Domaines: Mécanique des fluides [physics.class-ph]

Stefan Ivanell, Thomas Leweke, Sasan Sarmast, Hugo Umberto Quaranta, Robert F Mikkelsen, et al.. Comparison between experiments and Large-Eddy Simulations of tip spiral structure and geometry. Wake Conference 2015, Jun 2015, Visby, Sweden. pp.012018, ⟨10.1088/1742-6596/625/1/012018⟩. ⟨hal-01231462⟩