Numerical modeling of the long surface wave impact on a partially immersed structure in a coastal zone: Solitary waves over a flat slope

Abstract

This paper describes the numerical simulation of the solitary wave impact on a partially immersed and fixed structure located over a flat coastal slope. This topic is related to the need for assessment of the possible impact of long waves, such as tsunamis, on partially immersed structures in coastal waters. Numerical algorithms on a movable grid adapting to the motion of the shore point are developed for a fully nonlinear dispersive model and a dispersionless shallow water model. Their validation is carried out by comparing the obtained solutions with the data from laboratory experiments and with the results obtained using a fully nonlinear potential flow model. The study shows that the difference between the maximum wave impact on the body at the foot of the slope and near the shore can be up to 6 times. In many cases, the maximum horizontal component of the wave force occurs under the influence of the wave reflected from the shore, indicating the need to consider the influence of the shore-reflected wave when assessing the impact of long waves on structures located in coastal waters. Furthermore, the need to use runup algorithms instead of reflective boundary conditions (vertical wall) has been identified for gentler slopes, where the differences in the wave impact for these two configurations can be 2–3 times.