Turbulence analysis and multiscale correlations between synchronized flow velocity and marine turbine power production
|Author(s)||Duran-Medina Olmo1, Schmitt Francois G.1, Calif Rudy2, Germain Gregory3, Gaurier Benoit3|
|Affiliation(s)||1 : Univ Lille, CNRS, Univ Littoral Cote Opale, UMR 8187,LOG, F-62930 Wimereux, France.
2 : Univ Antilles, LARGE Lab Geosci & Energies, EA 4935, F-97170 Fouillole, Pap, France.
3 : IFREMER, Marine Struct Lab, 150 Quai Gambetta,BP 699, F-62321 Boulogne Sur Mer, France.
|Source||Renewable Energy (0960-1481) (Pergamon-elsevier Science Ltd), 2017-11 , Vol. 112 , P. 314-327|
|WOS© Times Cited||17|
|Keyword(s)||Marine energy, Turbulence, Multifractal energy cascade, Intermittency, Turbine power production, High frequency data rate|
The correlation between the flow turbulence and the performances of a marine current turbine is studied. First, the incoming flow encountered in the flume tank is characterized in the framework of fully developed turbulent cascades in the inertial range. The Reynolds number, the Kolmogorov dissipation scale and the integral scale, are estimated from flow measurements. The intermittency of the turbulence is characterized in the lognormal multifractal framework, and the influence of the turbulent flow on the turbine power is assessed.
The rotor speed control unit characteristics used for the turbine regulation induces non-negligible effects on the turbine behavior under fluctuations loads. Even if the power spectrum does not reveal any scale invariance, a multiscale analysis allows us to show the correlations between the turbulence time series and the power produced. The classical Mean Square Coherency function shows that for scales larger than 10 s, the upstream velocity and power have large correlations. In the framework of the Empirical Mode Decomposition method, such correlations are studied using the time-dependence intrinsic correlation analysis method. This method allows to zoom into time-frequency scales where the flow perturbations induced some modifications in power production.