The dynamic impact of surging waves on coastal structures via a wave–structure coupling model

The study of wave impact structures is a key focus of coastal protection and marine hazard mitigation. Fluid–structure coupling numerical simulation is a powerful technical method. This paper presents an integrated numerical framework combining the non-hydrostatic method with the immersed boundary method to investigate wave–structure interactions. The framework incorporates rigid body dynamics and a collision detection algorithm to resolve coupled hydrodynamic and structural interactions under wave force. A novel water elevation correction method with adaptive flux constraints at wave–structure interfaces successfully addresses mass conservation challenges during wave propagation over obstacles. Model validation through submerged bar benchmark tests demonstrates the accuracy of numerical model in wave propagation simulation. Combined wave flume experiments and parametric studies further validate the model in simulating coastal processes spanning wave generation, run-up dynamics, and structural responses. Comparative analysis reveals that simulated motion trajectories achieve good agreement with experimental measurements, particularly in capturing the effects of nonlinear wave–structure coupling. Numerical results of surge wave impacts on structures demonstrate shelter structures can reduce the impact forces by 50%, with system-scale analysis revealing stabilized force attenuation of approximately 15% under increasing structural density. An attenuation coefficient analysis quantifies the relationship between the number of sheltering structures and the reduction in wave force.