Numerical simulation of wave–current interaction using a RANS solver

• A numerical model for the interactions between ocean waves and currents.
• An increase of a following current velocity significantly prolongs the wave length.
• Waves with a shorter period have more intensive interaction with the ambient current.

A numerical model is developed to study the wave propagation in the presence of a steady current flow. This model is based on Reynolds-Averaged Navier–Stokes (RANS) equations with k−εk−ε turbulence closure scheme. A novel volume of fluid (VOF) method is applied to accurately capture the water free surface. The current flow is initialized by imposing a steady inlet velocity on one domain end and pressure outlet on the other end, while the desired wave is generated by an internal wave-maker from mass source term of mass conservation equation. Simulated water surface profile and velocity distribution agree well with experimental measurements of Umeyama (2011), indicating that this model has a great ability in simulating wave–current interaction. The validated model is then used to investigate the effects of wave period and current velocity on regular wave–current induced water surface profile and velocity distribution. The propagation of a solitary wave traveling with a following/opposing current is also numerically investigated by this model.