Assessing the turbulence in a tidal estuary and the effect of turbulence on marine current turbine performance

• Published in: Progress in Renewable Energies Offshore : Proceedings of the 2nd International Conference on Renewable Energies, 2016 (RENEW2016) pp. 573 - 579
• Main Authors: Thiébaut, M, Sentchev, A, Schmitt, F G, Le Kien, T
• Format: Conference Proceeding
• Language: English
• Published: Leiden Taylor & Francis Books Ltd 01.01.2016
• Subjects: Creeks & streams; Energy industry; Engineering; Estuaries; Field study; Flow velocity; Fluid dynamics; Ocean currents; Power; Scaling; Tidal currents; Time series; Turbines; Turbulence; Turbulence intensity; Turbulent flow; Belgium; Europe
• ISBN: 9781138626270; 1138626279
• DOI: 10.1201/9781315229256-69

A series of tidal turbine tests were conducted in a tidal estuary (the Sea Scheldt, Belgium). Two in-stream vertical axis tidal turbines were tested in real conditions during several weeks in winter 2014 and late summer 2015. Tidal current velocity variations were continuously recorded by one ADCP, operating at 1 Hz and two ADV operating at 16 and 32 Hz. The measurements covered different tidal current regimes: strong flood and ebb flow with velocity above 1.2 m/s and also a flow reversal. Turbulence intensity and scaling properties of the turbulent flow such as dissipation rate (e), integral scale (L), and Kolmogorov scale (η) were quantified. The coherency spectrum between rotor velocity and output power generated by a Darrieus type turbine was established. The results show high correlation in low frequency range and low correlation in high frequency range. The overall performance of the turbine was assessed by evaluating the power coefficient, Cp. The mean value of Cp was found to be 0.25.