Impact of lateral turbine spacing on the performance of a multi-rotor tidal energy device

In this work, the impact of local blockage on the power production of a tidal array due to multiple turbines positioned in close proximity is studied. A numerical model of the HydroWing tidal energy device, which features multiple turbines on a retrievable wing, is being developed using geometry-resolved computational fluid dynamics (CFD). For this paper, the influence of two turbines at several spacings is considered. The CFD model is used to perform  quasi-static steady-state  simulations of two turbines in a twin rotor configuration, where a multiple reference frame (MRF) approach is used to simulate rotor rotation. The lateral spacing between the rotors is varied and the resulting impact on the axial loads and  power performance of the two turbines is studied, with the aim of identifying the optimal turbine spacing for the HydroWing device. The results will be used in future design optimisation work to minimize the levelized cost of energy of a large scale array using HydroWing technology at the proposed site for the Morlais tidal energy project.