Enhancing power conversion via wave-guiding walls for an oscillating water column device integrated into a straight coast: Normal and oblique wave incidence

Optimizing the utilization and design of marine infrastructure is pivotal for the innovative advancement and integration of the marine engineering sector, particularly in wave energy generation. This study investigated a cylindrical oscillating water column (OWC) device employing a U-shaped flow channel impulse turbine, integrated into a straight coast with wave-guiding walls functioning as wave-focusing structures. The performance of the wave-guiding walls was evaluated through analyzing the comprehensive wave power conversion characteristics and electrical power output under varying wave periods, incident wave angles, and turbine operating modes. Key findings include: Firstly, the highest preliminary-phase energy conversion efficiency achieved with wave-guiding walls was 1.17, representing a 140.2% improvement over configurations without wave-guiding walls. Secondly, while the subsequent-phase conversion efficiency showed low sensitivity to the presence of wave-guiding walls, notable differences were observed in the internal flow dynamics of the Ushaped flow channel and the operational characteristics of the turbine rotor. Thirdly, systems integrated into a conventional straight coast exhibited maximum electrical power output under long-period waves. In contrast, in systems with wave-guiding walls, an increased ultimate conversion efficiency in short-period waves led to the highest electrical power output. Finally, with wave-guiding walls, preliminary-phase efficiency increased significantly with the incident wave angle in short-period waves, while in long-period waves, a greater incident wave angle reduced preliminary-phase efficiency due to the stronger diffraction effects of long waves. These findings highlight the potential of wave-guiding walls to significantly enhance wave energy capture efficiency in OWC structures integrated into straight coasts, demonstrating their effectiveness and adaptability across diverse wave conditions.