A small segmented oscillating water column using a Savonius rotor turbine

This paper describes a project which addresses the use of a small segmented oscillating water column with three sections. The turbine utilizes cascaded Savonius rotors (one for each section), and this system is developed and tested for validation of the performance algorithms. This paper shows that the system is easily described using a simulation, while a small-scale wave-tank-based system is shown to generate electrical power. The system is suitable for a shoreline location such as a harbor wall, where waves are random and not orthogonal to the column. Conversion rates in the region of 20% are tabulated with an output of 25 W peak. This paper reports on the operation of the column with respect to the wave frequency and wavelength. The peak tip speed ratio of the turbine is investigated in the application and found to correlate with published data when the turbine operates in free (rather than ducted) airflow conditions. The turbine is fully characterizedthe generator is a brushless permanent-magnet machine connected to a diode bridge rectifier and a variable load.