Abstract

Blockage, the ratio between a turbine’s swept area and the channel cross-sectional area, affects the torque and thrust characteristics of the rotor. These effects are relevant for many reasons, including the calculation of mechanical, structural and mooring systems, energy production assessment, etc. The present work describes the analysis and validation of six different blockage correction methods for tidal turbines, described in literature, with blade-resolved RANS-CFD simulations. The simulations were performed to seven different blockage rations and 5 tip speed ratios for each blockage case. The blocked results were corrected with the different methods and compared to the quasi open-flow results as a measure of the effectiveness of each one of them, showing a relatively good agreement for 4 out of 6 methods. Finally, this paper provides practical recommendations regarding the application of the different correction methods, including an assessment of the required variables and their scope of application.