Enhancing energy capture: single- and dual-chamber oscillating water column devices under converging waves

A parabolic coast or wall concentrates incoming waves at its focal point, creating a high‑energy zone ideal for enhanced capture. Yet, how to efficiently harvest this concentrated energy remains unclear. Here we propose designs of single- and dual-chamber Oscillating Water Column (OWC) chambers for enhancing wave energy capture. A time‑domain higher‑order boundary element method, grounded in nonlinear potential flow theory, is coupled with a nonlinear pneumatic model-calibrated via geometric scaling, dual‑chamber coupling, and focused‑wave boundary tests-to simulate OWC performance. Under parabolic focusing, a bimodal resonance yields peak power absorption up to 17 times that of an isolated device, and a leeward perforation design boosts the single‑chamber capture ratio to 25 times baseline. A dual‑chamber configuration with an added semicircular chamber further elevates total absorbed energy and widens the effective bandwidth. This work provides practical design guidance for efficient wave-energy devices operating in focused-wave environments.