Tsunami disasters occurred frequently in recent years, causing huge damages to marine structures. Previous tsunami events suggest that mangroves have a certain mitigation effect on tsunami flow. Based on the dam break method, the tsunami flow was simulated in this study. The mitigation effect of mangroves on tsunami was investigated, and the container movement due to tsunami was also explored. The dam break experiment at the sluice gate shows that the dam break process includes the sudden drop stage, the quasi-steady stage, and the slow decrease stage. Higher storage water results in a faster dam break. The container movement due to tsunami flow includes the initial impact stage, the speeding up stage, and the constant speed stage. The impact and buoyant forces contribute its movement. The flow pattern of the tsunami wave attenuation due to mangrove forest indicates that the turbulent flow generated by the superposition of the trailing vortices is the main cause of energy dissipation, and the reasonable dense planting, symmetrical arrangement and staggered arrangement are beneficial to the reduction of tsunami wave energy. In addition, the distribution of triangular staggered mangroves, the reduction of tsunami flow intensity, the increase of container weight, and the increase of coastal slope are all beneficial to reducing the movement distance of containers. Based on the experimental data, a formula for calculating the tsunami attenuation coefficient of mangroves was proposed. In this study, the tsunami attenuation coefficient of mangroves ranged from 0.02 to 0.42.
The Ocean Engineering
tsunami attenuation coefficient