Experimental study of flow characteristics in hydrodynamic and aerodynamic L-shaped and U-shaped oscillating water column chambers

Recent research on oscillating water column (OWC) systems has primarily focused on chamber design, which serves as the main absorber for capturing wave energy. Geometric designs of L-shaped and U-shaped OWC chambers have been commissioned and constructed. However, studies addressing the comparative performance and optimization of L-shaped and U-shaped chambers remain limited. This study investigates the hydrodynamic and aerodynamic performance of OWC devices featuring innovatively designed L-shaped and U-shaped chambers, with adjustments made in laboratory settings. Experiments were conducted in a 2D wave flume laboratory equipped with a shallow-water piston-type wave generator. Four variations of wave heights, ranging from 0.0625 m to 0.25 m, and wave periods, from 1.77 s to 3.18 s, were tested, corresponding to sea conditions in the Arafura and Banda Seas, Indonesia. Key parameters, including free surface elevation, airflow velocity, and pressure differences, were measured to evaluate chamber performance. The results indicate that the geometry and design of OWC chambers significantly influence their ability to convert wave energy. The L-shaped chamber consistently outperformed the U-shaped chamber, achieving an optimal power output of 171 W under specific wave conditions, effectively converting incident wave energy into pneumatic power. In contrast, the U-shaped chamber exhibited lower efficiency due to suboptimal wave oscillations within the chamber. These findings highlight the advantages of the L-shaped chamber, particularly its superior ability to generate substantial free surface oscillations, velocity, and pressure in the chamber and airflow in the turbine duct. This study provides valuable insights into the optimization of OWC chamber designs, emphasizing the critical role of geometric configurations in enhancing energy capture efficiency under realistic sea conditions.