Overtopping Assessment of a Rubble Mound Breakwater with Innovative Armor Units: A Physical and Numerical Study

Leone, E.; Francone, A.; Paglialunga, A.; Ciardulli, F.; Aloisi, A., and Tomasicchio, G.R., 2024. Overtopping assessment of a rubble mound breakwater with innovative armor units: a physical and numerical study. In: Phillips, M.R.; Al-Naemi, S., and Duarte, C.M. (eds.), Coastlines under Global Change: Proceedings from the International Coastal Symposium (ICS) 2024 (Doha, Qatar). Journal of Coastal Research, Special Issue No. 113, pp. 804-808. Charlotte (North Carolina), ISSN 0749-0208. Rubble-mound breakwaters are essential for coastal defense, protecting ports and mitigating erosion. During storms, water overflow can cause circulating currents in protected zones. Integrating innovative armor units that efficiently dissipate energy is key in reducing wave overtopping. An experimental investigation has been conducted on a scaled model of a rubble-mound breakwater with innovative armor units at the EUMER (EUropean Maritime Environmental Research) laboratory, University of Salento, Italy. The model replicated a defense structure in the Arabian Gulf, protecting an artificial island. A critical section prone to overtopping has been built at a 1:15 model scale. The investigation analyzed the performance of the armor units in terms of wave overtopping under operational and extreme conditions, considering the Gulf's wave characteristics. To enhance reliability, the physical model investigation has been complemented by a numerical study. Numerical simulations have been performed using the OpenFoam C++ libraries and the IHFOAM multiphase flow solver. The VARANS equations solved the two-phase flow within the breakwater's porous media. To close the system of equations describing the turbulent flow, the k-ω SST turbulence model has been selected, due to the good trade-off between cost and accuracy. The VOF method has been applied to track the free surface elevation over time. The numerical simulations showed strong agreement with experimental observations, demonstrating IHFOAM as a reliable tool to predict wave overtopping phenomena.