Cavitation Measurements of Tidal Stream Turbines and effect of installation layout

Two reports present the results of a two-stage experimental campaign aimed at the study of hydrokinetic turbines operating in cavitating flow conditions. The activity is of primary importance for floating tidal turbines floating that operate in proximity of the free-surface. The activity has been carried out at the Depressurized circulating water channel of CNR-INM, Rome. Two turbine design by Schottel Hydro (Germany) were considered and tested in different installation layouts. During project phase I, and isolated turbine layout was considered, and in phase II a turbine installed downstream of a supporting strut was considered. In both cases, a wide range of turbine operating conditions was considered, by varying current flow speed, turbine rotational speed and pressure in the test section, in order to simulate design as well as off-design real operating conditions. The results allowed to determine a comprehensive characterization of the cavitating flow around the turbine blades and the effects of cavitation on turbine performance and radiated acoustic noise. The activity has been conducted in the framework of the H2020 MaRINET 2 project, with co-funding under the Trans-National Access program, with grants No. 1534 (Phase I) and grant ID f3152cb7-07ad-4de7-931e-b2e3991313d8 (Phase II).