Experimental Analysis of the Effect of a Submerged obstacle and Floating Wave Barrier in front of a Rubble Mound Breakwater on Diminishing the Damage Parameter

The aim of this research was to compare the performance of a submerged obstacle and floating wave barrier in the stability of rubble mound breakwaters based on the damage parameter. The submerged obstacle was attached to the toe, and the floating wave barrier was installed 50 cm from a reshaping breakwater. We carried out tests in a 35 m flume at SCWMRI. Random waves with the JONSWAP spectrum influenced the breakwater. We then analyzed the structure's reshaping using close-range photogrammetric imaging by constructing the DEM and DSM to record the displacement of rocks. Furthermore, we obtained the eroded area and the damage parameter from the integrated model at eight cross-sections at equal distances. We showed that the damage parameter increased by 39.12 and 44.44%, respectively, by increasing the relative wave height from 0.36 to 0.48 and 0.6. Also, the damage parameter increased by 22.94 and 28.26%, respectively, by increasing the relative wave period from 0.6 to 0.8 and 1. In addition, regarding different modes, we obtained the damage parameter in the breakwater without the submerged obstacle and the floating barrier 1.116 under random waves. The damage parameter decreased to 0.701 (i.e., 37.19%) by using the submerged obstacle, while the wave barrier reduced this parameter to 0.735 (i.e., 34.14%); thus, the obstacle has outperformed the wave barrier. Using the obstacle simultaneously with the wave barrier reduced the damage parameter by 51.79%, confirming the highest efficiency and performance among models. Consequently and based on the experiments and findings in this study, this model was suggested for adoption.