Experimental and numerical assessment of low-crested and emergent breakwaters with eco-engineered armour units

This study presents a comprehensive evaluation of the hydraulic performance of low-crested and emergent rubble mound breakwaters (RMBWs) armoured with Coastalock™, an ecologically engineered single-layer armour unit designed to enhance marine biodiversity while providing high hydraulic stability. The study relies on an integrated approach and combines large-scale physical experiments and numerical modelling using the IH2VOF solver to assess wave generation, transformation, transmission, and overtopping under irregular wave conditions. Physical model tests were conducted at the Large Wave Flume of the National Research Council of Canada's Ocean, Coastal and River Engineering Research Center (NRC-OCRE), while the numerical simulations recreated the tests to enhance the understanding of overtopping and wave transmission dynamics of eco-engineered breakwaters under varied hydrodynamic conditions, complementing the physical model tests and supporting the evaluation of IH2VOF as a predictive design tool. The numerical model effectively simulated the hydraulic response of the breakwater, showing consistent trends with the physical experiments. A calibrated roughness coefficient (γ f = 0.48) was identified for EurOtop-based overtopping predictions. The findings confirm the applicability of IH2VOF for simulating wave–structure interactions in RMBWs armoured with Coastalock units.