Investigation of wave-energy absorption by single and double oscillating water-column converters

摘要

This thesis discusses two series of experiments performed on a system of two oscillating water columns (OWCs). The system is a 1:10 scale model, where full scale means physical dimensions equal to a test plant at Toftestallen on the west coast of Norway. One of the experimental series was an attempt of phase-controlling the system in regular incident waves. The phase control was discrete and accomplished by means of controllable air valves. The opening and closing of the valves was varied to find an optimal control strategy for maximum power conversion. The other experimental series was on a transient wave radiating from the OWC model. From these experiments the impulse response matrix of the system was calculated and used to determine frequency domain hydrodynamic parameters and to define the basis of a time-domain mathematical model of the system. Experiments have also been performed on a single two-dimensional OWC of scale 1:30 in order to determine the linear power loss from friction in the water and the loss resistance describing these losses. These experiments were carried out in two parts, one concerning regular incident waves, the other a transient outgoing wave. The power loss for this model was found to be 13 - 20 % of the incident wave power and the loss resistance was 2.5 - 5.0 Ns/m. 76 refs., 44 figs., 1 tab.