On the Spectral Behaviour of the Turbulence-Driven Power Fluctuations of Horizontal-Axis Turbines

Georgios Deskos, Grégory Payne, Benoît Gaurier, Michael Graham

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23 Scopus Citations


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. dCL/dα) 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.

Original languageAmerican English
Article numberA13
Number of pages27
JournalJournal of Fluid Mechanics
StatePublished - 2020

Bibliographical note

Publisher Copyright:
© The Author(s), 2020.

NREL Publication Number

  • NREL/JA-5000-76583


  • horizontal-axis turbines
  • power fluctuations
  • rotationally-sampled spectra


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