Gravity wave scattering by barge integrated porous cages

Abstract

Porous cage structures have become a focal point in marine engineering research due to their exceptional performance and adaptability across diverse oceanic environments. This study examines gravity wave interaction with various configurations of rectangular barge-supported porous cages using physical model tests and numerical model based on the linearized potential flow theory. The boundary value problem is solved using the dual boundary element method with a quadratic pressure drop across the thin porous boundaries. The Nash-Sutcliffe efficiency coefficient is employed as a statistical index to quantitatively assess the correlation between the experimental and numerical results. The influence of porosity, incident wave height, cage width, pontoon width, and cage segmentation on the scattering coefficients (reflection, transmission, and energy loss) is systematically examined through parametric analysis. The investigation demonstrates that incorporating a 20% porous cage with the pontoon results in up to a 42% reduction in wave transmission. Seaward placement of cages proved more effective than lee-side positioning, evidenced by reduced wave reflection and transmission in intermediate and deep water conditions. Interestingly, wave transmission decreased by up to 25% with a threefold increase in pontoon width, resulting in a more sheltered lee side. The results of this study are expected to support the practical implementation and design optimization of nearshore aquaculture cages, floating breakwaters, floating solar photovoltaic platforms, and related multifunctional ocean structures.