One-way coupled Eulerian–Lagrangian strategy for wave propagation and impact on coastal areas

Coastal hazards have gained importance in recent years due to the increasing number of extreme phenomena induced by climate change. The numerical simulation of such events represents a considerable challenge, due to the high non-linearity of the problem, the broadness of the domain, and the diversity of the involved scales. Holistic three-dimensional simulations of the whole domain are typically too computationally demanding and may not be necessary for the wave propagation analysis, where reduced models based on shallow-water hypotheses can be employed. However, these simplified approaches fail when modeling the intricate impact phenomena that occur in coastal zones. To reduce the computational cost without losing accuracy, we propose a one-way coupled approach using a Shallow-Water Eulerian solver to model wave propagation in the far field, and a complete three-dimensional Navier–Stokes Lagrangian strategy to simulate the wave impacting the coastal areas. A computational interface is used to store the kinematic information during the far-field analysis and to transfer it as an inlet condition to the near-field solver. The accuracy, efficiency and robustness of the proposed approach are shown in both 2D and 3D by studying two experimental tests.