|Author(s)||Deskos Georgios1, Payne Gregory S.2, Gaurier Benoit3, Graham Michael4|
|Affiliation(s)||1 : Natl Renewable Energy Lab, Natl Wind Technol Ctr, Golden, CO 80401 USA.
2 : Ecole Cent Nantes, Lab Rec Hydrodynam Energet & Environm Atmosper, 1 Rue Noe, F-44300 Nantes, France.
3 : IFREMER, Marine Struct Lab, 150 Quai Gambetta,BP 699, F-62321 Boulogne, France.
4 : Imperial Coll London, Dept Aeronaut, London SW7 2AZ, England.
|Source||Journal Of Fluid Mechanics (0022-1120) (Cambridge Univ Press), 2020-12 , Vol. 904 , N. A13 , P. 27p.|
|WOS© Times Cited||10|
In this article we consider the spectral behaviour of turbulence-driven power fluctuations for a single horizontal-axis turbine. To this end, a small-scale instrumented axial-flow hydrokinetic turbine model (diameter = 0.724 m) is deployed in the long water flume situated in the laboratory facilities of IFREMER in Boulogne-sur-Mer, France, and synchronous measurements of the upstream velocity and the rotor are collected for different tip-speed ratios. The study confirms previous findings suggesting that the power spectra follow the velocity spectra behaviour in the large scales region and a steeper power law slope behaviour (-11/3) over the inertial frequency sub-range. However, we show that both the amplitude of the power spectra and low-pass filtering effect over the inertial sub-range also depend on the rotor aero/hydrodynamics (e.g. dC(L)/d alpha) and the approaching flow deceleration and not solely on the rotational effects. In addition, we present a novel semi-analytical model to predict the dominant blade-passing frequency harmonics in the high-frequency regime using the rotationally sampled spectra technique. For all calculations, the distortion of incoming turbulence is taken into account.
Deskos Georgios, Payne Gregory S., Gaurier Benoit, Graham Michael (2020). On the spectral behaviour of the turbulence-driven power fluctuations of horizontal-axis turbines. Journal Of Fluid Mechanics, 904(A13), 27p. Publisher's official version : https://doi.org/10.1017/jfm.2020.681 , Open Access version : https://archimer.ifremer.fr/doc/00655/76710/