Experimental investigation on a dual chamber floating oscillating water column moored by flexible mooring systems

A series of 1:50 model tests are conducted to study the motion responses and energy harvesting performance of a novel dual chamber floating oscillating water column device moored by three flexible mooring systems in regular and irregular waves. This novel energy conversion device consists of one traditional oscillating water column chamber and one Backward Bend Duct Buoy chamber. The mooring systems, include one modified Catenary Anchor Leg Mooring concept and two compact mooring systems, designed for station keeping of this specific floating device. Strong nonlinearities of mooring tension are found, especially in the low wave period sea conditions. It is also found that the surge and yaw motion has significant differences when the device moored by the different mooring systems. The pitch and heave natural periods are derived from their Responses Amplitude Operator curves. The performance of spectral methods in mooring fatigue damage estimation depends on mooring configuration and material. It is seen that the attached clump weights affect the fatigue damage of the compact mooring rope. It has been found that the novel device shows good performance in energy harvesting within broad range of wave periods, and the influence of mooring configuration on energy conversion performance depends on the wave height.