Numerical Modelling of Breaking Wave Impacts on Seawalls with Recurved Parapets Using qaleFOAM

This paper presents a numerical comparative study on the interaction between breaking waves and vertical seawalls with a recurved parapet attached using the hybrid solver qaleFOAM, which couples a two-phase incompressible Navier-Stokes (NS) solver with the quasi-Lagrangian-Eulerian finite element method solver based on the fully nonlinear potential theory. The focus of the comparison is to reveal the possible scale effect as a result of improper scaling of the viscous effects in the model test adopting the Froude similarity in wave-structure interaction practices. For this purpose, both a 1:8 scale model test and a full-scale experiment with a large prototype model are used in the study. In the NS solver of the qaleFOAM, both a laminar model and k-co shear stress transport model are adopted. The wave elevations at different locations and the impact pressure on the seawall are investigated. It is concluded that the performance of the qaleFOAM is similar for both the scaled and full-scale modelling; the viscosity, turbulence, and air compressibility may be critical for the formation of the breaking waves, which eventually affects the prediction of the impact load.