Experimental study on performance assessment of Savonius rotor type wave energy converter in an experimental wave flume

The power generation of regular water waves from a horizontal-axis single Savonius rotor is experimentally investigated in an experimental wave flume in the context of the performance assessment of the rotor in intermediate-to-shallow water depths for different parametric conditions. A number of prototypes with multiple blades of 3–5 with the same diameter and blade curvature angle are fabricated in-house and tested to measure both the long-term average torque and power generated at different submergence levels, wave heights and wave periods. The experiments are performed in the wave-current flume equipped with a piston-type wave maker with an active wave absorption capability. The energy performance of the rotor is comparatively assessed for each experimental test case based on quantitative comparison of obtained wave-to-mechanical energy conversion efficiency (ECE) to suggest a possible optimum blade number, positioning and wave physical conditions for the investigated range of wave flow characteristics. It is found that higher ECE values can be achieved at higher wave heights and blade numbers for the lower wave periods when the rotor is placed at the water surface and/or just below the surface. This study provides a proper guideline for performance analysis of such device(s) for further studies.