Effect of Variation in Diameter on the Rotation of Half Submerged Wave Driven Savonius Turbines – An Experimental Investigation

Ocean wave energy is a promising field for renewable energy. Turbine is a major challenge area for economy of this field. An interest in using turbines directly for wave energy conversion has been increasing recently as turbines have been used successfully to harness the energy of flow throughout history. However, the field of dynamics of a wave driven turbine is vastly unexplored. This study focuses on experimentally investigating the effects of variation in the diameter of Savonius type of turbines on their rotation while they are driven by identical waves and rotate freely. A total of seven turbines with a diameter between 0.013m and 0.080m were tested on identical waves with a height of 0.030m. It was generally noted that the motion of all the turbines was synchronised with that of the driving wave cycles. The turbines having a diameter smaller than wave height exhibited a predominantly continuous rotational motion with a fluctuating speed. Furthermore, a decrease in the fluctuation was noted with increasing moment of inertia of the turbine.