This paper presents a numerical investigation of the interaction between the breaking waves and vertical wall attached recurved parapet for both a small 1:8 scale and a large 1:1 scale model using a hybrid solver, qaleFOAM. qaleFOAM applies the domain-decomposition approach in which a two-phase incompressible Navier-Stokes (NS) solver InterFoam couples with the Quasi Lagrangian-Eulerian Finite Element Method (QALE-FEM). The practical performance of qaleFOAM is demonstrated by comparing its prediction with the experimental data, including the wave elevation and pressure on the vertical wall and recurved parapet. Good prediction of the breaking wave elevation is achieved, whilst to better address the high frequency, highly stochastic impulsive pressure problem, a compressible qaleFOAM solver should be adopted.
Understanding of the loads caused by the large wave heights is important, especially when facing more frequent extreme weather events. Rather than increasing the sea wall height, it has been proved that the recurved parapet is more efficient in reducing the wave overtopping by discharging part of seawater back into the sea. Therefore, investigation of the behavior between the breaking wave and the curved parapet is essential. To address this issue, a wide range of numerical simulations and model tests have been carried out. The breaking wave impact on a vertical wall is simulated using a compressible multiphase flow solver and the results show that the variability of maximum impact pressure on the wall is very large. The air pocket impact shows a plateau peak adjacent to the impact position, whilst flip through impact exhibits a single sharp peak at the location where the wave trough strikes the wave crest (Gao, F., et al, 2015). Molines et al. (2020) studied the influence of a parapet on wave overtopping of mound breakwaters with crown walls. The authors noticed a reduction in the dimensionless mean wave overtopping discharges when a parapet was constructed. Ravindar and Sriram (2021) studied the behavior of parapets for a range of breaking monochromatic waves to understand the influence of the type of breaker–structure interaction on the loading pattern on the overall structure.
