Results from blade element momentum and RANS analyses of a practical full-scale horizontal axis tidal current turbine

Results are presented herein for the hydrodynamic behaviour of a practical full-scale horizontal axis tidal current turbine, based on blade element momentum (BEM) and Reynolds-averaged Navier Stokes (RANS) solutions. Power and thrust coefficients are predicted from both models and an analysis of the wake behind the turbine comes from the RANS solution. By practical, we make reference to a turbine rotor that has been conservatively designed with respect to in-service loads and which therefore features blade sections with large thickness to chord ratios (18% at tip to 55% at root). The BEM predictions were based on available experimental data and newly-generated data from Xfoil and RANS solutions. This highlighted the importance of using appropriate blade data. These RANS solutions for the blade sections, carried out using the open-source solver Code Saturne, also functioned as a subcomponent verification and validation exercise for the turbine simulations, carried out with the same solver and turbulence model. All of these simulations were carried out as part of the PerAWaT project, commissioned by the Energy Technologies Institute, and are intended to provide data from which a parametric model of the wake can be determined, with the ultimate aim of being able to predict the performance of tidal current turbines in arrays.