The purpose of the experiments is to compare how three different turbine designs perform in unsteady flow conditions: in turbulence and in surface waves, generated in the wave and current flume tank of Ifremer at Boulogne-sur-mer. An additional objective is to characterise the unsteady inflow conditions, and correlate them to the measured turbine loads.

The turbine performance is measured in steady and unsteady flow, through torque and thrust transducers. The inflow is characterised through 2-components and 3-components LDV systems and PIV measurements. The two LDV systems are used to take simultaneous 2-point measurements of the turbulent flow, at several locations in the turbine plane. This is done in an empty tank, i.e. when the turbine is not deployed. The purpose is to measure the spatial correlation of turbulent gusts in the turbine plane, by measuring at two locations simultaneously.

When the turbine is deployed, one velocity measurement point (using the 2-components LDV) is always acquired upstream of the turbine hub and in synchronization with the turbine parameters. Time-resolved PIV recording at 15 Hz is used to measure the flow adjacent to the turbine when operating in turbulence. The PIV plane includes the upper half of the turbine diameter, i.e. the edge of the turbine nose is just visible on the bottom right side of the PIV plane. These PIV measurements are acquired in synchronization with the turbine parameters.

These LDV and PIV measurements enable the correlation and the coherence between the inflow characteristics and the turbine parameters to be processed.