Focusing Monochromatic Water Surface Waves by Manipulating the Phases Using Submerged Blocks

Focusing water surface waves is a promising approach for enhancing wave power in clean energy harvesting. This study presents a novel method that simplifies the wave-scattering problems of large-scale three-dimensional (3D) focusing blocks by decomposing them into scattering problems of two-dimensional (2D) phase regulators. The phase lags of transmitted waves over such 2D structures of various heights and thicknesses are investigated using both linear potential flow theory and numerical simulations based on smoothed-particle hydrodynamics (SPH). Due to propagation path differences of a converging wave, our approach compensates for circular phase differences within a maximal collection angle by optimizing the geometries of 2D phase regulators. Based on this concept, we designed three types of submerged structures and tested them in a 3D numerical water tank. All three structures successfully converted monochromatic plane waves into circular waves, which then converged at the designated focal point. This study offers a potential method to enhance the collection efficiency of monochromatic and regular waves for wave energy converters.