ABSTRACT
Low power data acquisition systems that are either supplemented or completely powered by renewable energy can be very useful for oceanographic purposes. The spar-buoy Oscillating-Water-Column (OWC) concept, typically studied for large scale energy production, can be re-designed to meet the power requirements of oceanographic applications, which results in a much smaller device working outside resonance conditions under typical sea states, and therefore with a smaller energy conversion efficiency. Preliminary experimental results are presented for a 1:10 th scale model of a spar-buoy OWC, undertaken in a wave channel. A calibrated orifice plate was used to model the flow characteristic of an impulse turbine, which will be used in the full-scale system. The experimental set-up is presented. Measurements of the relative buoy-OWC motion, air chamber pressure, and power absorption are examined, for regular and irregular wave conditions. The results show the presence of non-linear effects, caused by viscous flow and turbine damping. For an energy period of 8 s, the device presents a capture width ratio of about 0.03, which makes it adequate for the supply of oceanographic sensors in North Atlantic wave climates.
