Abstract
The impact of an array layout on turbine performance and loading is of interest for full scale tidal arrays. To determine the expected power output from an array the interaction between turbines needs to be understood. The work presented in this paper considers three array layout cases in order to study the impact of the positioning of an upstream turbine on a second downstream turbine. The first case provided the data for the turbine in a purely turbulent flow. The second and third cases used an upstream turbine to generate a wake to impact on the downstream turbine. In both cases, the stream-wise spacing was maintained at 3.5 m or ~4 downstream turbine diameters. The results show that a turbine placed partially in the wake of an upstream turbine produce reduced averaged torque, thrust and blade bending moments in comparison to a turbine sat in a purely turbulent flow. When the turbine is fully placed in the wake of an upstream turbine, the loading values were further reduced. However, when normalised, the turbine positioned in a partial wake showed the greatest reduction in values and the largest fluctuations of all the performance characteristics.