2023 Volume 79 Issue 18 Article ID: 23-18155
There is serious concern that the wave-overtopping disasters will increase due to the global warming accompanied by the sea level rise and intense typhoons in the near future. As a countermeasure, we proposed a low-cost and simple mooring type wave overtopping prevention by utilizing a cylindrical body for the vertical seawalls. The both ends of the cylindrical body are moored using rope to the front face of the seawalls. This mooring allows that the cylindrical body moves following the wave motion in front of the seawall. Hence this method has several merits, e.g., low cost, ease of construction and maintenance, and so on. By conducting model experiments, Nakatani et al. (2019) confirmed that the proposed method can efficiently reduce the wave-overtopping. In addition, the tension acting on the mooring ropes, which is one of the important factors for the design of the prevention method, was investigated. Furthermore, numerical simulations were performed to estimate the reduction of wave-overtopping rate by this method. The numerical model was “DualSPHysics” which is based on the Smoothed Particle Hydrodynamics (SPH) model. The numerical simulations at that time, however could not reproduce the mooring ropes, and were simple with a fixed cylindrical body.
In this study, we retry to reproduce the behavior of the proposed wave-overtopping countermeasure including the mooring ropes by the numerical simulation, and re-examined whether the numerical simulation is useful for evaluating the mooring type overtopping countermeasure.
As a result, the numerical simulation sufficiently reproduced the motion of the moored cylindrical body preventing the wave overtopping, and the tension acting on the mooring ropes was reasonably evaluated. Although there is still room for improvement in the numerical model, the numerical simulation can be a useful tool to investigate the performance of the proposed method in detail.
