Experimental study of a backward bent duct buoy wave energy converter: Effects of the air chamber and center of gravity height

The backward-bent duct buoy (BBDB) wave energy converter (WEC) is a floating oscillating water column (OWC) device with high conversion efficiency and low mooring requirements. This study experimentally investigates the effects of air chamber volume, chamber top shape, and center of gravity height on the wave energy capture performance of BBDB WEC. The results indicate that increasing the air chamber's volume enhances conversion performance. When the air chamber volume is increased from 0.0162 m³ to 0.0233 m³, the maximum capture width ratio (CWR) increases by 0.14 and 0.13 at wave amplitudes of 0.015 m and 0.025 m, respectively. An oblique cut prism chamber improves performance under low wave periods. When using a chamber with an inclined top, conversion performance exceeds that of a rectangular chamber, with the maximum CWR increasing from 1.09 to 1.40 at a wave height of 0.015 m and from 0.82 to 1.01 at a wave height of 0.025 m. Additionally, changes in center of gravity height primarily affect conversion efficiency during the pitch resonance period. These findings contribute to the structural optimization and performance enhancement of BBDB WECs.