Abstract
This paper presents the results of three dimensional numerical simulations of a three-bladed horizontal axis tidal turbine (HATT) under realistic turbulent tidal flow conditions. All results provided incorporate the Reynolds-averaged NavierStokes (RANS) Shear Stress Transport (SST) turbulence model. Simulations cover a range of tip speed ratios (TSR = 3 – 4.5) and flow velocities (1.6, 1.8 and 2.05 m/s) at a fixed hub pitch angle of approximately 28°. Simulations are performed at a timedependent, turbulent inflow velocity based on measurements obtained in Grand Passage, Nova Scotia. Thrust and power coefficients are compared to numerical results obtained in steady flow for validation purposes. The results show a good level of agreement between steady and transient simulations. Results of a power production comparison show a small reduction in power production (4%), when comparing turbine operation in a realistic unsteady tidal flow to operation in a steady flow. Near field and far field wake propagation is also investigated and compared to the wake obtained with a steady flow.