Numerical Simulation of 5th-Order Stokes Wave in Finite Water Depth Based on Momentum Source Method

Abstract

For numerical simulation of structure-wave interaction, the wave generation with high accuracy is prime to analyze the wave loads and motions of the structure. Based on the fifth-order Stokes theory, a two-dimensional viscous wave flume, which was modeled using the commercial CFD solver ANSYS-FLUENT, was applied to the generation and propagation of regular waves in finite water depth. With the user-defined function provided by the solver, the momentum source term and boundary condition, which are used for the wave generation and dissipation, were developed to ensure the accuracy of wave simulation with large steepness. In addition, the wave flume was separated into two regions, which are governed by the laminar model and turbulent model, respectively. The separation of laminar and turbulent regions can alleviate the side effect of turbulence on the accuracy of wave generation. In order to validate the present method, the regular wave propagating with different steepness in finite water depth were simulated. The numerical results were in good agreement with the theoretical ones. The study showed that the present method was effective for the simulation of Stokes wave in finite water depth, especially effective to improve the numerical accuracy in case of large wave steepness.