A one-way coupling method from the two-layer Boussinesq model to the Reynolds-averaged Navier–Stokes solver for simulating wave–structure interactions

To simulate the ocean wave–structure interactions, a one-way coupling method from the two-layer Boussinesq model to the RANS (Reynolds-averaged Navier–Stokes) solver is proposed and investigated. The first model is a potential Boussinesq model based on the finite difference approach, which is highly accurate and well-suited to describing long-distance wave propagation. The second model is the OpenFOAM model that solves the RANS equations, more suited to model viscous and turbulent effects around the structure's vicinity. The two models are overlapped by setting a relaxation zone in the computational zone. The wave motion quantities are accurately estimated from the two-layer Boussinesq model and mapped point to point to the RANS model as the incident wave signals. Three large-scale experimental and numerical results are presented to validate the coupling model, which simulates wave–structure interactions under various wave conditions. The coupling model successfully reproduces the solitary wave breaking on a mild slope, the focused wave impact on a vertical cylinder, and the regular wave overtopping over a seadike. Furthermore, it minimizes the CPU (Central Processing Unit) burden and owing to the reduction of total simulated cells, the structure vicinity cells can be refined to provide better simulation results.