The project is a feasibility study on the use of flexible blades to increase the durability and survivability of tidal turbines. The highly turbulent flow experienced by tidal turbines leads to continuous load variations limiting the fatigue endurance. It is proposed to use flexible blades in order to control the flow field around the blades and allow constant stresses on the turbine's blades and shaft. Under the effect of a variation of the onset flow velocity at a certain location along the blade span, the flexible blade will change the local angle of attack and the foil shape. The new flow field around the blade section will be as such to minimise the load change on the blade section. The reduced, if not completely avoided, load variations will enhance the fatigue endurance of the blade and the shaft.

Potential Impact:
The project could provide proof of concept that flexible blades can allow low-amplitude stress variations in turbulent flow conditions. The potential industrial impact would be significant because it would solve one of the key challenges of the emerging tidal energy industry. Being a short feasibility study, the results will be used as preliminary data for a wider study, which will be proposed as a research proposal to the next joint MoST/EPSRC call on marine energy.

The project will produce new high-quality flow measurements of a tidal turbine blade in highly turbulent flow conditions. These data will form an experimental benchmark for the validation of numerical codes, which aim to predict the flow field and/or forces on 3D wings in turbulent flow conditions, including applications in aeronautics, turbomachinery, and ocean engineering.

A novel potential flow code able to model the vorticity of turbulent flow will be developed, contributing to the fundamental research on turbulent flow and how to numerically model turbulence.

The project will lead to new collaborations between three institutes with a strong research activity on marine energy: the University of Edinburgh, the Ocean University of China and the Dalian University of Technology. Three researchers from the UoE (the PI, and two PGRs) will collaborate with the two researchers from OUC and two researchers from DUT, leading to an international team of seven researchers. Several opportunities of knowledge exchange, including more than 45 days of secondments in total, will enable long-lasting collaborations and synergies between these researchers.

Within the UoE team, one PGR with significant experience in PIV flow measurements will be employed at 20% of the time in order to provide guidance, advice and support to the project team on PIV flow measurements, thus this project will be opportunity for the research team to gain specialist expertise in PIV flow measurements.