Two-phase CFD Simulation of Breaking Waves Impacting a Coastal Vertical Wall with a Recurved Parapet

Abstract

Breaking wave impacts on coastal protections are simulated using a multi-phase 3D CFD (Computational Fluid Dynamics) software, named neptune cfd, focusing on a particular lay-out composed of a plane slop-ing bottom and a vertical wall with a recurved parapet on top of it. The goal is to assess the capabilities and performances of the solver to simulate the propagation of regular waves over the variable bathymetry (in-cluding shoaling and nonlinear e ff ects), the depth-induced breaking process and the interaction of these breaking waves with the vertical wall. We simulate two experiments involving similar geometry of the seabed and vertical wall, performed at two di ff erent scales (1:8 for case A and 1:1 for case B), as described in Ravindar et al. (2021). After a descrip-tion of the CFD solver and its numerical methods, the model is applied to the simulation of the two cases involving extremely high impact pressure peaks at some places of the wall surface. Numerical results are compared with experimental measurements regarding both free surface elevation and pressure on the wall. In general, a good agreement of the simulations with the measurements is obtained for free surface elevation, including the breaking zone. The time history of pressure variations dur-ing wave impacts is correctly reproduced. Although the measured maximum impact pressure peaks exhibit some variability among successive wave impacts, the order of magnitude of these maximum peaks is well predicted for case A. For case B, however, the maximum impact pressures are somewhat underestimated by the current simulations, requiring further tests and improvements. This work is a contribution to the bench-mark “Comparative Study on Breaking Waves Interactions with Vertical Wall attached with Recurved Parapet in Small and Large Scale” set up for the ISOPE’2022 conference.