A double-layer non-hydrostatic model for simulating wave-structure and wave-jet interactions

Waves are pivotal factors in coastal areas, and effective simulation of wave-related phenomena is crucial. This paper presents the extension of the non-hydrostatic model from single-layer σ transformation to double-layer σ transformation in order to stabilize submerged structures and jet orifices under wave environment. The Lagrangian-Eulerian method is adopted for tracking the free surface in this model. This updated model is validated through comparisons against a series of test cases, including wave structure interaction and horizontal jet under waves. A good agreement between the model results and experimental data is achieved, demonstrating the capability of the developed model to fix the submerged object to resolve wave-structure and wave-jet interactions. Thus, the proposed double-layer σ model can be seen as a useful tool to simulate problems in coastal dynamics. • A double-layer sigma system is used to fix the submerged object in non-hydrostatic model. • Lagrangian-Eulerian method is utilized for tracking of the free surface. • Comparison between single-layer and double-layer sigma coordinate systems is performed. • Synthetic Eddy Method is employed to generate jet outlet velocity boundary. • Successful validation with analytical solutions and experiments.