Numerical investigation of a horizontal axis tidal turbine

Horizontal Axis Tidal Turbines (HATTs) are one of the most promising technologies available for power generation from tidal energy. In this study, the performance of a twin bladed HATT based on a NACA63-618 cross-section was numerically studied using a Reynolds Averaged Navier-Stokes (RANS) solver with k-ω turbulence model. The power and thrust coefficients at different tip speed ratios were calculated and validated using previously published experimental data. Simulation results indicated that the maximum efficiency of the tidal turbine is approximately 40%, occurring at a tip speed ratio of 6. The pressure distribution at three different sections of the blade span was investigated for three values of tip speed ratio. Boundary layer separation is evident on the suction surface towards the root of the blade section at a tip speed ratio of 5. As tip speed ratio is increased to 7, the separation does not occur.