Preliminary Numerical Assessment of Marine Turbines With Rigid Blades Using Low Reynolds Approach

Abstract Tidal turbines with morphing blades could increases the mean time to failure of turbine blades and drive trains by mitigating power and loads fluctuations associated with the larger scales of the turbulent tidal stream flow. However, the numerical modeling of this fluid-structure interaction problem would require expensive high performance computing infrastructure to obtain results in a reasonable time. In order to develop this analysis capability, the goal of the present work is to identify the numerical setup details in OpenFOAM framework to assess the performance of the Oxford tidal turbine with rigid blades. For this, thrust and torque predictions were used to assess the performance of this turbine considering the steady inflow condition of with a rotor tip-speed ratio of 5.82 and turbulence intensity of 3.1%. For the near-wall treatment, a κ-ω SST turbulence model with low Reynolds number approach was used. Thrust and torque predictions using a grid with element size of 1.5%D in the turbine region have and error of 0.5% and 14.8% respectively. Also, a 1/15 power law velocity profile was assumed to assess its effect on load fluctuations. Further, a reduced order model will eventually be implemented to capture blade deformation and reduce load fluctuations.