Optimal design of a thin-wall diffuser for performance improvement of a tidal energy system for an AUV

The numerical optimisation is validated by two sets of physical model tests conducted with a single turbine without diffuser and the same turbine integrated with the diffuser (DATT) in a cavitation tunnel and a circulating water channel. These tests demonstrated a performance enhancement for the turbine with the optimal diffuser by almost doubling the power coefficient of the turbine without the diffuser. However, the performance enhancement was dependent upon the pitch angle of the turbine.